Micro-optic probes for neurology

Abstract

To provide an imaging system for a patient comprising an imaging probe.SOLUTION: An imaging probe 100 comprises: an elongate shaft 110 for insertion into the patient, and comprising a proximal end 111, a distal portion 119, and a lumen extending between the proximal end and the distal portion; a rotatable optical core comprising a proximal end and a distal end, and configured to optically and mechanically connect with an interface unit; a probe connector 102 positioned on the elongate shaft proximal end, and surrounding at least a portion of the rotatable optical core; and an optical assembly 130 positioned in the elongate shaft distal portion and proximate the rotatable optical core distal end, the optical assembly configured to direct light to tissue and collect reflected light from the tissue. A shear-thinning fluid can be provided between the elongate shaft and the rotatable optical core, e.g., to reduce undesired rotational variations of the rotatable optical core.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) This application claims the benefit of U.S. Provisional Patent Application No. 62 / 322,182, filed April 13, 2016, entitled "Micro Optic Probes for Neurology," and U.S. Provisional Patent Application No. 62 / 148,355, filed April 16, 2015, entitled "Micro-Optic Probes for Neurology," the contents of each of which are incorporated herein by reference in their entirety for all purposes. This application is related to U.S. Provisional Patent Application No. 62 / 212,173, filed August 31, 2015, entitled "Imaging System Includes Imaging Probe and Delivery Devices," the contents of which are incorporated herein by reference in their entirety for all purposes.

[0002] The present concepts relate generally to imaging systems, and more particularly to neuroimaging systems that include an imaging probe, an imaging console, and a delivery device. [Background technology]

[0003] Imaging probes for imaging various locations inside a patient (e.g., intravascular probes for imaging a patient's heart) are commercially available. Existing imaging probes are limited in their ability to reach certain anatomical locations due to their size and rigidity. Existing imaging probes are inserted over a guidewire, which can reduce the flexibility of placement of the imaging probe and can further limit the use of the delivery catheter into which the imaging probe is inserted. What is needed is an imaging system with a probe that is smaller in diameter, more flexible, and capable of being advanced to the patient location to be imaged without the use of a guidewire, as well as a system with a delivery device compatible with this improved imaging probe. Summary of the Invention

[0004] In accordance with one aspect of the inventive concept, an imaging system for a patient is configured to generate images of the patient, the imaging probe including an elongate shaft for insertion into the patient, the elongate shaft having a proximal end, a distal portion, and a lumen extending between the proximal and distal portions, a rotatable optical core having proximal and distal ends and configured to optically and mechanically connect to an interface unit, a probe connector disposed on the proximal end of the elongate shaft and surrounding at least a portion of the rotatable optical core, and an optical assembly disposed within the distal portion of the elongate shaft adjacent the distal end of the rotatable optical core and configured to direct light to tissue and collect reflected light from the tissue.

[0005] In some embodiments, the imaging probe includes a shear-thinning fluid located within the distal portion of the elongate shaft, for example, a shear-thinning fluid configured to reduce undesirable rotational fluctuations of the rotatable optical core (e.g., and the attached optical assembly 130) while avoiding excessive loads on the rotatable optical core.

[0006] In some embodiments, the imaging probe further includes at least one space reducing element disposed between the elongate shaft and the rotatable optical core, the at least one space reducing element being configured to reduce fluctuations in rotational velocity of the rotatable optical core. The at least one space reducing element may be disposed within at least a portion of the distal portion of the elongate shaft. The at least one space reducing element may be configured to reduce fluctuations in rotational velocity by increasing the shear thinning properties of the shear thinning fluid.

[0007] In some embodiments, the imaging probe further includes an inertial assembly configured to reduce variations in the rotational speed of the rotatable optical core.

[0008] In some embodiments, the imaging probe further includes an impeller configured to be attached to the rotatable optical core and configured to resist rotation of the rotatable optical core when the rotatable optical core is retracted.

[0009] In some embodiments, the imaging probe further includes a stiffening element embedded in the elongate shaft configured to resist deflection of the elongate shaft and having an optically transparent portion.

[0010] In some embodiments, the imaging probe further comprises a reduced inner diameter portion of the elongate shaft, the reduced inner diameter portion configured to reduce fluctuations in rotational speed of the rotatable optical core.

[0011] In some embodiments, the imaging system is configured to generate three-dimensional images upon retraction of the elongate shaft.

[0012] In some embodiments, the imaging system is configured to detect and / or quantify malapposition of a flow diverter implanted within a patient.

[0013] In some embodiments, the imaging system is configured to provide quantitative and / or qualitative information for use in determining the size of the flow diverter to be implanted within the patient and / or the placement of the flow diverter within the patient, wherein the quantitative and / or qualitative information may include information regarding parameters selected from the group consisting of perforator location, perforator shape, neck size, mesh density of the flow diverter, and combinations thereof.

[0014] In some embodiments, the imaging system is configured to image a stent retriever at least partially disposed within a thrombus in a patient. The imaging system may be configured to image at least one of thrombus not entangled with the stent retriever or thrombus not removed by the stent retriever.

[0015] In some embodiments, the imaging system is configured to quantify a volume of thrombus in the patient, where the quantified thrombus may be selected from the group consisting of residual thrombus in an acute stroke, thrombus remaining after a thrombectomy procedure, thrombus present after flow diverter implantation, and combinations thereof.

[0016] In some embodiments, the imaging system is configured to provide implantation site information, and the implantation site information is used to select a particular implantable device for implantation within the patient's body. The system may further include an implantable device for implantation within the patient's body, the implantable device may include a device selected from the group consisting of a stent, a flow diverter, and combinations thereof. The implantable device may be selected based on implantable device parameters selected from the group consisting of porosity, length, diameter, and combinations thereof.

[0017] In some embodiments, the imaging system is configured to provide porosity information of a device implanted within a patient's body. The porosity information may include the porosity of a portion of the implanted device that will be positioned adjacent to a side branch of a blood vessel in which the implanted device will be placed. The system may be configured to provide the porosity information based on a wire diameter of the implanted device. The system may further include an implanted device, which may include a device selected from the group consisting of a stent, a flow diverter, and combinations thereof. The imaging system may be further configured to provide information regarding the implantation of a second device within the patient's body. The first implanted device may include a stent, and the second implanted device may include a flow diverter. The first implanted device may include a flow diverter, and the second implanted device may include a flow diverter. The imaging system may be further configured to provide images during deployment of the implanted device. The imaging system may be further configured to allow modification of the implanted device during positioning of the optical assembly adjacent to the implanted device. The modification may include a modification of the porosity of the implanted device. The system may further include a balloon catheter configured to effect the porosity modification.

[0018] In some embodiments, the imaging system is configured to image at least one perforator artery of the patient. The at least one perforator artery may have a diameter of 50 μm or greater. The system may further include a treatment device. The treatment device may include a device selected from the group consisting of a stent retriever, an embolic coil, an embolic coil delivery catheter, a stent, a covered stent, a stent delivery device, an aneurysm treatment graft, an aneurysm treatment graft delivery device, a flow diverter, a balloon catheter, and combinations thereof.

[0019] In some embodiments, the system further includes at least one guide catheter. The at least one guide catheter may include a microcatheter. The microcatheter may have an inner diameter of at least 0.0165 inches and at most 0.027 inches. The microcatheter may have an inner diameter of at least 0.021 inches and at most 0.027 inches.

[0020] In some embodiments, the imaging probe is configured and designed to reach human blood vessels.

[0021] In some embodiments, the imaging probe is configured to reach the blood vessels of the brain.

[0022] In some embodiments, the elongate shaft comprises a material selected from the group consisting of FEP, PTFE, Pebax, PEEK, polyimide, nylon, and combinations thereof.

[0023] In some embodiments, the elongate shaft comprises a material selected from the group consisting of stainless steel, nickel titanium alloy, and combinations thereof.

[0024] In some embodiments, the elongate shaft has a first portion comprising a metal tube and a second portion comprising a braided shaft.

[0025] In some embodiments, the elongate shaft comprises a hydrophobic material configured to reduce a change in length of the elongate shaft when the elongate shaft is exposed to a fluid.

[0026] In some embodiments, the outer diameter of the elongate shaft varies along the length of the elongate shaft.

[0027] In some embodiments, the inner diameter of the elongate shaft varies along the length of the elongate shaft.

[0028] In some embodiments, the outer diameter of the elongate shaft is greater than or equal to 0.006 inches and less than or equal to 0.022 inches.

[0029] In some embodiments, the outer diameter of the elongate shaft is about 0.0134 inches.

[0030] In some embodiments, the inner diameter of the elongate shaft is greater than or equal to 0.004 inches and less than or equal to 0.012 inches. The wall thickness of the elongate shaft is about 0.003 inches.

[0031] In some embodiments, the outer diameter of the elongate shaft is 500 μm or less.

[0032] In some embodiments, the outer diameter of the elongate shaft is 1 mm or less.

[0033] In some embodiments, the outer diameter of the elongate shaft is about 0.016 inches. The outer diameter of at least the most distal 30 cm of the elongate shaft may be 0.016 inches or less.

[0034] In some embodiments, the elongate shaft may have an outer diameter of about 0.014 inches. The elongate shaft may be configured for advancement through the vasculature without a guidewire or delivery device. At least the distal-most 30 cm of the elongate shaft may have an outer diameter of 0.014 inches or less.

[0035] In some embodiments, the elongate shaft has an intermediate section proximal to the distal section, the distal section having a larger outer diameter than the intermediate section. The distal section of the elongate shaft may have a larger inner diameter than the intermediate section. The larger outer diameter distal section may surround the optical assembly.

[0036] In some embodiments, the length of the elongate shaft is 100 cm or more. The length of the elongate shaft may be 350 cm or less.

[0037] In some embodiments, the length of the elongate shaft is 200 cm or more. The length of the elongate shaft may be 220 cm or more. The length of the elongate shaft may be 240 cm or more. The length of the elongate shaft may be about 250 cm.

[0038] In some embodiments, the elongate shaft further has an intermediate portion, and the inner diameter of the distal portion of the elongate shaft is larger than the inner diameter of the intermediate portion of the elongate shaft. The inner diameter of the distal portion of the elongate shaft may be 0.002 inches or more larger than the inner diameter of the intermediate portion of the elongate shaft. The outer diameter of the distal portion of the elongate shaft may be similar to the outer diameter of the intermediate portion of the elongate shaft. The outer diameter of the distal portion of the elongate shaft may be larger than the outer diameter of the intermediate portion of the elongate shaft. The outer diameter of the distal portion of the elongate shaft may be 0.001 inches or more larger than the outer diameter of the intermediate portion of the elongate shaft. The wall thickness of the distal portion of the elongate shaft may be less than the wall thickness of the intermediate portion of the elongate shaft. The distal portion of the elongate shaft may comprise a more rigid material than the intermediate portion of the elongate shaft. The distal portion of the elongate shaft may comprise a stiffening element.

[0039] In some embodiments, the distal portion of the elongate shaft has a rapid exchange guidewire lumen. The guidewire lumen may be 150 mm or less in length. The guidewire lumen may be 15 mm or more in length. The guidewire lumen may be 25 mm or more in length.

[0040] In some embodiments, the distal portion of the elongate shaft includes an optically transparent window, and the optical assembly is disposed within the optically transparent window. The length of the optically transparent window may be less than 20 mm or less than 15 mm. The optically transparent window may comprise a material selected from the group consisting of Pebax, Pebax 7233, PEEK, amorphous PEEK, polyimide, glass, sapphire, nylon 12, nylon 66, and combinations thereof. The elongate shaft may have at least a first portion disposed proximal to the optically transparent window, and the first portion may comprise a braided shaft. The elongate shaft may further have a second portion disposed proximal to the first portion, and the second portion may comprise a metal tube. The length of the optically transparent window may be greater than or equal to 1 mm and less than or equal to 100 mm. The length of the optically transparent window may be approximately 3 mm. The optically transparent window may comprise a material selected from the group consisting of nylon, nylon 12, nylon 66, and combinations thereof.

[0041] In some embodiments, the elongate shaft includes a stiffening element. The stiffening element may be disposed at least at a distal portion of the elongate shaft. The stiffening element may be configured and designed to resist rotation of the distal portion of the elongate shaft during rotation of the rotatable optical core. The stiffening element may terminate proximal to the optical assembly. The stiffening element may include a coil. The stiffening element may include a metal coil wrapped around PTFE. The stiffening element may include a coil wound in a direction such that rotation of the rotatable optical core tightens the metal coil. The imaging probe may further include a fluid disposed between the rotatable optical core and the elongate shaft, the metal coil configured to reduce twisting of the elongate shaft due to a torque force applied by the fluid.

[0042] In some embodiments, the elongate shaft has a distal end, and the imaging probe includes a spring tip attached to the distal end of the elongate shaft. The spring tip may include a radiopaque portion. The length of the spring tip may be between 2 cm and 3 cm.

[0043] In some embodiments, the elongate shaft has a proximal portion configured and designed to be placed in a service loop, and the proximal portion of the elongate shaft has a different configuration than the remainder of the elongate shaft, which may include a larger outer diameter or a thicker wall.

[0044] In some embodiments, the system further includes a fluid disposed within the lumen of the elongate shaft and a fluid interaction element disposed within a distal portion of the lumen of the elongate shaft, the fluid interaction element configured to interact with the fluid to increase a load on the rotatable optical core during rotation of the rotatable optical core. The fluid interaction element may include a coil disposed within the lumen of the elongate shaft. The fluid interaction element may have a non-circular cross-section of the lumen. The non-circular cross-section may have a shape selected from the group consisting of a polygonal cross-section of the lumen of the elongate shaft, a protrusion into the lumen of the elongate shaft, a recess in the inner diameter of the elongate shaft, and combinations thereof. The fluid may include a low-viscosity fluid. The viscosity of the fluid may be 1000 Cp or less.

[0045] In some embodiments, the imaging probe further includes a first sealing element located within the lumen of the elongate shaft, the sealing element being disposed between the rotatable optical core and the elongate shaft and configured to slidingly engage the rotatable optical core (e.g., to seal when the rotatable optical core rotates) and resist fluid flow around the sealing element. The first sealing element may be disposed within a distal portion of the elongate shaft. The imaging probe may further include a first liquid disposed proximate to the optical assembly and a second fluid disposed proximate to the rotatable optical core, the first sealing element being disposed between the first and second liquids. The first liquid may have a first viscosity and the second liquid may have a second viscosity greater than the first viscosity. The first sealing element may be further configured to resist rotation of the rotatable optical core. The first sealing element may include a hydrogel. The first sealing element may include an adhesive coupled to the elongate shaft. The first sealing element may include a UV-curable adhesive coupled to the elongate shaft. The rotatable optical core may include a material that does not bond to adhesives. The first sealing element may include a compatible material. The compatible material may include silicone. The system may further include a second sealing element disposed between the rotatable optical core and the elongate shaft, the second sealing element may be configured to slidingly engage the rotatable optical core and may be further configured to resist fluid flow around the second sealing element, and the imaging probe may further include a fluid disposed between the first sealing element and the second sealing element. The first sealing element and the second sealing element may be separated by a distance of 1 mm or more and 20 mm or less. The viscosity of the fluid disposed between the first sealing element and the second sealing element may be 10 Cp or more and 100 Cp or less. The first sealing element may be disposed proximal to the optical assembly, and the second sealing element may be disposed distal to the first sealing element.

[0046] In some embodiments, the imaging probe includes a sealing element disposed adjacent the proximal end of the elongate shaft. The sealing element may be disposed between the elongate shaft and the probe connector.

[0047] In some embodiments, the rotating optical core comprises a single mode glass fiber having an outer diameter of at least 40 μm and at most 175 μm.

[0048] In some embodiments, the rotating optical core comprises a single mode glass fiber having an outer diameter of at least 80 μm and at most 125 μm.

[0049] In some embodiments, the rotatable optical core includes a polyimide coating.

[0050] In some embodiments, the outer diameter of the rotatable optical core is between 60 μm and 175 μm inclusive. The outer diameter of the rotatable optical core may be about 110 μm.

[0051] In some embodiments, the rotatable optical core comprises a material selected from the group consisting of silica glass, plastic, polycarbonate, and combinations thereof.

[0052] In some embodiments, the numerical aperture of the rotating optical core is about 0.11.

[0053] In some embodiments, the numerical aperture of the rotating optical core is 0.11 or greater.

[0054] In some embodiments, the numerical aperture of the rotating optical core is about 0.16.

[0055] In some embodiments, the numerical aperture of the rotating optical core is about 0.20.

[0056] In some embodiments, the rotatable optical core is constructed and designed to rotate in a single direction.

[0057] In some embodiments, the rotatable optical core is constructed and designed to rotate in two directions.

[0058] In some embodiments, the rotatable optical core is configured to be retracted within the elongate shaft. The system may further include a purge medium introduced between the rotatable optical core and the elongate shaft. The purge medium may provide a function selected from the group consisting of refractive index matching, lubrication, bubble purging, and combinations thereof.

[0059] In some embodiments, the outer diameter of the optical assembly is between 80 μm and 500 μm. The outer diameter of the optical assembly may be about 150 μm.

[0060] In some embodiments, the outer diameter of the optical assembly is 125 μm or greater.

[0061] In some embodiments, the length of the optical assembly is between 200 μm and 3000 μm inclusive. The length of the optical assembly may be about 1000 μm.

[0062] In some embodiments, the optical assembly includes a lens. The lens may include a GRIN lens. The focal length of the lens may be greater than or equal to 0.5 mm and greater than or equal to 10.0 mm. The focal length of the lens may be approximately 2.0 mm. The lens may include a ball lens.

[0063] In some embodiments, the optical assembly includes a reflective element.

[0064] In some embodiments, the optical assembly includes a lens, a reflective element, and a connecting element (coupling element, joining element), where the connecting element positions the reflective element relative to the lens. The connecting element may include an element selected from the group consisting of tubing, flexible tubing, heat shrink, an optically transparent arm, and combinations thereof. The connecting element may position the reflective element at a distance of 0.01 mm to 3.0 mm from the lens. The connecting element may position the reflective element at a distance of 0.01 mm to 1.0 mm from the lens. The reflective element may comprise a cleaved portion of a larger assembly. The reflective element may include a portion of a wire. The wire may include a gold wire. The lens may include a GRIN lens. The lens may have at least one of an outer diameter of 150 μm or a length of 1000 μm. The lens may further include a coreless lens positioned proximal to and optically connected to the GRIN lens.

[0065] In some embodiments, the imaging probe includes an inertial assembly, the inertial assembly being positioned proximate to the optical assembly.

[0066] In some embodiments, the imaging probe includes an inertial assembly, the inertial assembly further including a wound hollow core cable having a proximal end and a distal end, the distal end of the wound hollow core cable being fixed to a rotatable optical core at a location proximal to the optical assembly, and the proximal end of the wound hollow core cable not being attached to the optical core.

[0067] In some embodiments, the imaging probe includes an inertial assembly including a fluid within a lumen of the elongate shaft and a mechanical resistance element disposed in a distal portion of the optical core, the mechanical resistance element being in contact with the fluid and configured to resist rotation of the rotatable optical core.

[0068] In some embodiments, the imaging probe includes an inertial assembly that is constructed and designed to provide inertial damping that increases with rotational speed.

[0069] In some embodiments, the imaging probe includes an inertial assembly, the inertial assembly including a protrusion from the rotatable optical core. The protrusion may be configured and designed to frictionally engage the elongate shaft. The protrusion may be configured and designed to create a shear force that applies a load to the rotatable optical core during rotation.

[0070] In some embodiments, the imaging probe includes an inertial assembly, the inertial assembly including a protrusion from the elongate shaft. The protrusion may be configured and designed to frictionally engage the rotatable optical core. The protrusion may be configured and designed to create a shear force that applies a load to the rotatable optical core during rotation. The protrusion may be created by heat treating the elongate shaft.

[0071] In some embodiments, the imaging probe includes an inertial assembly, the inertial assembly including a constriction from the elongate shaft, and the system may further include at least one cuff configured to contract the elongate shaft to form the constriction.

[0072] In some embodiments, the imaging probe includes an inertial assembly, and the inertial assembly includes an impeller.

[0073] In some embodiments, the imaging probe includes an impeller, the impeller configured and designed to create a winding load on the rotatable optical core during rotation.

[0074] In some embodiments, the imaging probe includes an impeller, the imaging probe further including a fluid within the lumen, the impeller configured to engage the fluid during rotation of the rotatable optical core.

[0075] In some embodiments, the imaging probe comprises an impeller, and the impeller comprises a turbine.

[0076] In some embodiments, the imaging probe includes an impeller configured to frictionally engage the elongate shaft during rotation of the rotatable optical core.

[0077] In some embodiments, the imaging probe includes an impeller, the impeller including blade-shaped microstructures.

[0078] In some embodiments, the imaging probe includes an impeller, which includes a flywheel.

[0079] In some embodiments, the imaging probe includes a stiffening element.

[0080] In some embodiments, the imaging probe includes a stiffening element, the stiffening element including a wire coil embedded in an elongate shaft, the wire helix shape and the pullback spiral rotation pattern of the optical assembly being aligned but offset by approximately 1 / 2 of the wire helix during retraction, such that the imaging beam of the optical assembly passes between the wire helixes.

[0081] In some embodiments, the imaging probe includes a stiffening element, the stiffening element including windings disposed on a rotatable optical core.

[0082] In some embodiments, the imaging probe includes a stiffening element, the stiffening element including a stiffening member embedded in the elongate shaft, the shape of the stiffening member and the retraction spiral pattern of the optical assembly being aligned but offset by approximately 1 / 2 of a wire spiral during retraction, such that the imaging beam of the optical assembly passes between the wire spirals.

[0083] In some embodiments, the imaging probe has a reduced portion of the elongate shaft. The imaging probe may include at least one band that is wrinkled around the elongate shaft and may clamp the elongate shaft to form the reduced portion of the elongate shaft. The at least one band may seal between the rotatable core and the elongate shaft. The reduced portion of the elongate shaft may include a heat-treated portion of the elongate shaft.

[0084] In some embodiments, the imaging probe further includes a fluid disposed within the lumen of the elongate shaft. The fluid may be configured to reduce fluctuations in the rotational speed of the rotatable optical core. The system may further include a sealing element disposed proximate the proximal end of the elongate shaft, the sealing element configured to maintain the fluid within the lumen. The fluid may include a first fluid disposed around the optical assembly and a second fluid disposed around the rotatable optical core. The first fluid may have a first viscosity, and the second fluid may have a second viscosity greater than the first viscosity. The second fluid may be configured and designed to reduce fluctuations in the rotational speed of the rotatable optical core. The system may further include a sealing element disposed between the first and second fluids. The fluid may include a gel. The fluid may include a shear-thinning fluid. The fluid may include a shear-thinning gel. The fluid may be configured to provide lubricity. The fluid may be configured to facilitate maintaining the rotatable optical core centered on the elongate shaft during rotation of the rotatable optical core. The viscosity of the first fluid may be 10 Pa·S or more and 100,000 Pa·S or less. -1The fluid may be configured to reduce the viscosity to a level of approximately 3 Pa·S at a shear rate of 100 s. The fluid may include a lubricant configured to reduce friction between the rotatable optical core and the elongate shaft. The fluid may include a first fluid and a second fluid, the second fluid may be disposed within the elongate shaft proximal to the optical assembly, and the first fluid may be disposed within the elongate shaft proximal to the second fluid. The imaging probe may further include a sealing element between the first and second fluids. The sealing element may be disposed at a distance of 1 mm to 20 mm from the optical assembly. The sealing element may be disposed at a distance of approximately 3 mm from the optical assembly. The viscosity of the first fluid may be at least 10 Pa·S and at most 100,000 Pa·S. The first fluid may include a shear-thinning fluid. The first fluid may be disposed at a shear rate of 100 s. -1The imaging system may be configured to pressurize the fluid in the lumen. The imaging system may be configured and designed to pressurize the fluid to reduce bubble formation and / or bubble growth. The imaging system may be configured to pressurize the fluid in the lumen to a pressure of 100 psi or greater. The imaging system may include a pressurizing assembly configured to pressurize the fluid. The pressurizing assembly may include a check valve. The fluid may include a lubricant. The lubricant may be configured to reduce friction between the rotatable optical core and the elongate shaft when at least a portion of the elongate shaft is positioned distally adjacent the carotid artery. The fluid may include a high-viscosity fluid. The elongate shaft may be configured and designed to expand when the fluid is pressurized. The elongate shaft may be configured and designed to expand to a first inner diameter when the fluid is at a first pressure. The elongate shaft may be configured and designed to expand to a second inner diameter when the fluid is at a second pressure. The elongate shaft may be configured and designed to become more rigid when the fluid is pressurized. The elongate shaft may be configured and designed to increase the space between the rotatable optical core and the elongate shaft during expansion by the pressurized fluid. The elongate shaft may be configured and designed to remain at least partially expanded when the fluid pressure is reduced.

[0085] In some embodiments, the imaging probe further includes a torque shaft having a proximal end and a distal end, the torque shaft being fixedly attached to the rotatable optical core such that rotation of the torque shaft rotates the rotatable optical core. The torque shaft may include stainless steel. The outer diameter of the torque shaft may be greater than or equal to 0.02 inches and less than or equal to 0.09 inches. The outer diameter of the torque shaft may be about 0.025 inches. The length of the torque shaft may be about 49 cm. The torque shaft may have dimensions selected from the group consisting of an inner diameter of about 0.015 inches, an outer diameter of about 0.025 inches, and combinations thereof. The wall thickness of the torque shaft may be greater than or equal to 0.003 inches and less than or equal to 0.020 inches. The wall thickness of the torque shaft may be about 0.005 inches. The distal end of the torque shaft may be located within 60 cm of the optical connector. The distal end of the torque shaft may be located within 50 cm of the optical connector. The distal end of the torque shaft may be located more than 50 cm from the optical assembly. The distal end of the torque shaft may be located 100 cm or more away from the optical assembly. The imaging system may further include a retraction assembly configured and designed to retract at least one of the rotatable optical core or the elongate shaft, and the distal end of the torque shaft may be located proximal to the retraction assembly. The imaging probe may further include a fixation tube disposed between the torque shaft and the rotatable optical core. The fixation tube may be attached to at least one of the torque shaft or the rotatable optical core with an adhesive.

[0086] In some embodiments, the imaging system further includes a visualization marker configured and designed to identify the location of the optical assembly on a second image generated by a separate imaging device. The separate imaging device may include a device selected from the group consisting of an X-ray imaging device, an ultrasound imaging device, an MRI device, and combinations thereof. The visualization marker may be located on the optical assembly. The visualization marker may be located a fixed distance from the optical assembly. The imaging system may further include a connecting element that couples the visualization marker to the optical assembly.

[0087] In some embodiments, the imaging probe may include a plurality of markers configured and designed to provide a regulatory function. At least one of the plurality of markers may include at least one of a sealing element or a rotational damper. The plurality of markers may include two or more markers selected from the group consisting of radiopaque markers, ultrasound reflective markers, magnetic markers, and combinations thereof. The plurality of markers may be disposed on a rotatable optical core. The plurality of markers may be disposed on an elongate shaft.

[0088] In some embodiments, the imaging system further includes a console including components selected from the group consisting of a rotation assembly, a retraction assembly, an imaging assembly, an algorithm, and combinations thereof.

[0089] In some embodiments, the imaging system further includes a rotation assembly configured and designed to rotate the rotatable optical core. The rotation assembly may include a motor. The imaging system may further include a retraction assembly configured and designed to retract at least one of the rotatable optical core or the elongate shaft. The imaging system may further include a translatable slide, and the rotation assembly may be disposed on the translatable slide. The rotation assembly may be configured and designed to be positioned independently of the position of the retraction assembly. The retraction assembly may be configured and designed to be positioned closer to the patient than the rotation assembly. The rotation assembly can provide a motive force to the retraction assembly. The rotation assembly may include a drive cable that provides a motive force to the retraction assembly. The elongate shaft may be configured and designed to be retracted by the retraction assembly. The elongate shaft may have a proximal portion configured and designed to provide a service loop during retraction by the retraction assembly. The rotation assembly may rotate the rotatable optical core at a speed of 20 rps or more and 2500 rps or less. The rotating assembly may rotate the rotatable optical core at a speed of approximately 250 rps. The rotating assembly may rotate the rotatable optical core at a speed of up to 25,000 rps. The rotating assembly may be configured and designed to rotate the rotatable optical core at a variable rotational speed. The imaging system may further include a sensor configured to generate a signal, and the rotational speed may be varied based on the sensor signal. The sensor signal is indicative of a parameter selected from the group consisting of vessel tortuosity, vessel stenosis, the presence of a blood clot, the presence of an implanted device, and combinations thereof. The rotating assembly may be configured to prompt an operator to vary the rotational speed. The rotating assembly may be configured to automatically vary the rotational speed. The rotating assembly may be configured to increase the rotational speed when collecting image data from the region of interest.

[0090] In some embodiments, the imaging system further includes a retraction assembly configured and designed to retract at least one of the rotatable optical core or the elongate shaft. The retraction assembly may be configured and designed to retract the rotatable optical core without retracting the elongate shaft. The retraction assembly may be configured and designed to retract both the rotatable optical core and the elongate shaft. The retraction assembly may be configured and designed to retract the rotatable optical core and the elongate shaft simultaneously. The retraction assembly may be configured and designed to retract the rotatable optical core and the elongate shaft together. The imaging probe may include a fluid between the rotatable optical core and the elongate shaft, and the retraction assembly may be configured and designed to retract while minimizing bubble formation in the fluid. The distal portion of the elongate shaft may include an optically transparent window, and the optical assembly may be disposed within the optically transparent window. The length of the optically transparent window may be 6 mm or less, 15 mm or less, or 20 mm or less. The length of the optically transparent window may be 5 mm or more and 50 mm or less. The optically transparent window may have a length of about 10 mm or about 12 mm. The optically transparent window may have a length of 4 mm or less. The optically transparent window may have a length of about 3 mm. The elongate shaft may have an outer diameter of 0.025 inches or less. The elongate shaft may have an outer diameter of 0.016 inches or less. The elongate shaft may have an outer diameter of 0.014 inches or less. The retraction assembly may be configured and designed to retract the elongate shaft. The elongate shaft may have a proximal portion configured and designed to provide a service loop during retraction by the retraction assembly. The retraction assembly may include a telescoping retraction assembly. The telescoping retraction assembly may include a disposable motor. The imaging probe may include a Tuohy valve, and the retraction assembly may operably engage the Tuohy valve during retraction. The retraction assembly may be configured to perform retraction for a period of at least 0.1 seconds and not more than 10 seconds. The retraction assembly may be configured to perform retraction for a period of about 4 seconds.The retraction assembly may be configured and designed to retract at least one of the rotatable optical core or the elongate shaft over a distance of approximately 50 mm. The retraction assembly may be configured and designed to retract at least one of the rotatable optical core or the elongate shaft over a distance of approximately 75 mm. The retraction assembly may be configured and designed to retract at least one of the rotatable optical core or the elongate shaft over a distance of at least 20 mm and at most 150 mm. The retraction assembly may be configured and designed to allow an operator of the system to select the retraction distance. The retraction assembly may be configured to perform retraction at a speed of at least 3 mm / sec and at most 500 mm / sec. The retraction assembly may be configured to perform retraction at a speed of approximately 50 mm / sec. The retraction assembly may be configured and designed to retract at least one of the rotatable optical core or the elongate shaft at a variable retraction speed. The imaging system may further include a sensor configured to generate a signal, and the retraction speed may be changed based on the sensor signal. The sensor signal can represent a parameter selected from the group consisting of vessel tortuosity, vessel stenosis, the presence of a blood clot, the presence of an implanted device, and combinations thereof. The retraction assembly may be configured to prompt an operator to vary the retraction speed. The retraction assembly may be configured to automatically vary the retraction speed. The retraction assembly may be configured to decrease the retraction speed when visualizing the region of interest. The imaging system may further include a catheter device including at least one of a vascular introducer or a guide catheter, and an elongate shaft insertable within the catheter device. The retraction assembly may be attachable to the catheter device. The imaging system may further include a catheter device including at least one of a vascular introducer or a guide catheter, and an elongate shaft insertable within the catheter device. The retraction assembly may be configured and designed to be positioned within 20 cm of the catheter device.

[0091] In some embodiments, the imaging system further includes an imaging assembly configured to provide light to and collect light from the rotating optical core. The imaging assembly may include a light source configured to provide light to the rotating optical core. The imaging assembly may include a fiber optic rotary joint including an optical core configured to transmit light to and receive light from the rotating optical core. The rotating optical core may include a fiber having a first numerical aperture, and the imaging assembly may include an imaging assembly optical core having a second numerical aperture different from the first numerical aperture. The first numerical aperture may be approximately 0.16, and the second numerical aperture may be approximately 0.11. The imaging system may further include an adapter configured to attach the imaging probe to the imaging assembly. The adapter may include a lens assembly configured to match various numerical apertures. The adapter may be configured for use in multiple clinical procedures (but fewer procedures than the imaging assembly). The adapter may include a fiber having a numerical aperture selected to minimize coupling losses between the imaging probe and the imaging assembly. The numerical aperture of the adapter fiber may be approximately equal to the geometric mean of the numerical aperture of the rotatable optical core and the numerical aperture of the imaging assembly.The numerical aperture of the adapter fiber may be approximately equal to the arithmetic mean of the numerical aperture of the rotatable optical core and the numerical aperture of the imaging assembly.

[0092] In some embodiments, the imaging system further includes an algorithm. The imaging system may further include a sensor configured to generate a signal, and the algorithm may be configured to analyze the sensor signal. The sensor signal may represent light collected from the tissue. The sensor signal may represent parameters related to vessel tortuosity, vessel narrowing, the presence of a blood clot, the presence of an implanted device, and combinations thereof.

[0093] In some embodiments, the imaging system further includes at least one guide catheter configured to slidingly receive the imaging probe. The imaging system may further include a irrigation fluid delivery assembly configured to deliver a irrigation fluid between the at least one guide catheter and the imaging probe. The irrigation fluid may include saline and / or a contrast agent (e.g., a radiopaque contrast agent). The irrigation fluid delivery assembly may be configured to deliver the irrigation fluid at a rate of approximately 6 ml / sec. The imaging system may further include a irrigation fluid, which may include an iodinated contrast agent having an iodine concentration of 50 mg / ml to 500 mg / ml. The irrigation fluid may include a fluid having a viscosity of 1.0 Cp to 20 Cp at a temperature of approximately 37°C. The at least one guide catheter may include a first guide catheter including an optically transparent window, and the optical assembly may be configured and designed to be disposed within the optically transparent window. The first guide catheter may include a microcatheter having an inner diameter of 0.021 inches to 0.027 inches. The first guide catheter may include a microcatheter having an inner diameter of not less than 0.0165 inches and not more than 0.027 inches. The at least one guide catheter may further include a second guide catheter configured to slidingly receive the first guide catheter.

[0094] In some embodiments, the imaging system further includes a torque tool configured and designed to operably engage the elongate shaft and thereafter apply a torsional force to the elongate shaft.

[0095] In accordance with another aspect of the inventive concept, there is provided a method of using the imaging system described herein.

[0096] [Incorporated by reference] All publications, patents, and patent applications mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication, patent, or patent application was specifically and individually indicated to be incorporated by reference. [Brief explanation of the drawings]

[0097] The above and other objects, features and advantages of embodiments of the inventive concepts will be apparent from the detailed description of the preferred embodiments, as illustrated in the accompanying drawings, in which like reference characters indicate the same or similar elements. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the preferred embodiments.

[0098] [Figure 1] 1 is a schematic diagram of an imaging system including an imaging probe, an imaging console, and one or more transport devices, consistent with the concepts of the present invention. [Figure 1A] 2 is an enlarged view of a distal portion of the shaft of the imaging probe of FIG. 1, which is consistent with the concepts of the present invention. [Figure 2] 1 is a perspective view of an imaging probe having a metal coil disposed at the distal portion of the shaft of the imaging probe, consistent with the concepts of the present invention; [Figure 3] 1 is a graph illustrating non-uniform rotational distortion. [Figure 4] 1 is a side cross-sectional view of a distal portion of an imaging probe having a thinned portion of the shaft disposed around an optical assembly, consistent with the concepts of the present invention; [Figure 5] 1 is a side cross-sectional view of a distal portion of an imaging probe containing two fluids within the shaft of the imaging probe, consistent with the concepts of the present invention. [Figure 6] 1 is a perspective view of an impeller and a side cross-sectional view of a distal portion of an imaging probe including the impeller, consistent with the concepts of the present invention; [Figure 7] 1 is a side cross-sectional view of a proximal portion of an imaging probe including a pressure element, consistent with the concepts of the present invention; [Figure 8] 1 is a side cross-sectional anatomical view of a system including a guide catheter, an imaging probe, and a treatment device, each positioned within a patient's blood vessel, consistent with the concepts of the present invention. [Figure 9]9 is a side cross-sectional anatomical view of the system of FIG. 8 after the guide catheter has been partially retracted, consistent with the concepts of the present invention. [Figure 10] 9 is a side cross-sectional anatomical view of the system of FIG. 8 after the imaging probe has been advanced through the treatment device, consistent with the concepts of the present invention. [Figure 11] 9 is a side cross-sectional anatomical view of the system of FIG. 8 as the imaging probe is being retracted through the treatment device, consistent with the concepts of the present invention. [Figure 12] 1 is a side cross-sectional anatomical view of a system including an imaging probe and a therapeutic device, consistent with the concepts of the present invention. [Figure 13] FIG. 1 is a side cross-sectional view of an imaging probe including a precision spacing between a rotating optical core and a shaft, the spacing being set to provide capillary action for fluids, consistent with the concepts of the present invention. [Figure 14] 1 is a partial assembly view of an imaging probe including a shaft, a rotating optical core, and a torque shaft, consistent with the concepts of the present invention. [Figure 15A] 1A-1C are side cross-sectional views of an imaging probe at successive steps in the deployment of the shaft of the imaging probe through an internal fluid, consistent with the concepts of the present invention; [Figure 15B] 1A-1C are side cross-sectional views of an imaging probe at successive steps in the deployment of the shaft of the imaging probe through an internal fluid, consistent with the concepts of the present invention; [Figure 15C] 1A-1C are side cross-sectional views of an imaging probe at successive steps in the deployment of the shaft of the imaging probe through an internal fluid, consistent with the concepts of the present invention; [Figure 16] 1 is a side cross-sectional view of a distal portion of an imaging probe including a distal marker positioned relative to an optical assembly, consistent with the concepts of the present invention. [Figure 17] 1 is a side cross-sectional view of a distal portion of an imaging probe including two sealing elements, consistent with the concepts of the present invention. [Figure 18]1 is a side cross-sectional view of a distal portion of an imaging device including a lens and a deflector separated and connected by a protrusion, consistent with the concepts of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0099] The terms used herein are for the purpose of describing particular embodiments and are not intended to limit the inventive concepts. Moreover, while embodiments of the inventive concepts may include several novel features, none of these alone is responsible for the desirable attributes of the invention or is an essential element for practicing the inventive concepts described herein. As used herein, the singular forms "a," "one," "the," and "the" are intended to include the plural forms as well, unless the context clearly dictates otherwise.

[0100] It will be understood that the words "comprising" (and any form of "comprising", e.g., "include" and "included"), "having" (and any form of "having", e.g., "has" and "had"), "comprising" (and any form of "comprising", e.g., "include" and "included"), or "containing" (and any form of "containing", e.g., "containing" and "contained"), as used herein, specify the presence of specified features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof.

[0101] Although terms such as "first," "second," and "third" may be used herein to describe various constraints, elements, components, regions, layers, and / or portions, it is understood that these constraints, elements, components, regions, layers, and / or portions are not intended to be limiting. These terms are merely used to distinguish one constraint, element, component, region, layer, or portion from another constraint, element, component, region, layer, or portion. Thus, without departing from the teachings of this application, a first constraint, element, component, region, layer, and / or portion described below may be referred to as a second constraint, element, component, region, layer, and / or portion.

[0102] Furthermore, when an element is referred to as being "on," "mounted," "connected," or "coupled" to another element, it is understood that the element may be directly on or above, connected to, or coupled to the other element, or there may be one or more intervening elements. In contrast, when an element is referred to as being "directly on," "directly mounted," "directly connected," or "directly coupled" to another element, there are no intervening elements. Other language used to describe the relationship between elements (e.g., "between" and "directly between," "adjacent" and "directly adjacent," etc.) should be interpreted similarly.

[0103] Furthermore, when a first element is said to be "in," "on," and / or "within" a second element, it is understood that the first element may be located within the interior space of the second element, within a portion of the second element (e.g., within a wall of the second element), on the exterior and / or interior surface of the second element, or a combination of one or more of these.

[0104] Spatial terms, such as "below," "below," "lower," "above," "upper," "higher," etc., may be used to describe the relationship of one element and / or feature to another element(s) and / or feature(s), e.g., as shown in the figures. It is understood that spatial terms are intended to encompass different orientations of the device in use and / or operation, not just the orientation shown in the figures. For example, if the device in the figures were inverted, elements described as being "below" and / or "below" other elements or features would then be positioned "above" the other elements or features. The device may be otherwise oriented (e.g., rotated 90 degrees or to another orientation), and the spatial terms used herein would be interpreted accordingly.

[0105] As used herein, "and / or" should be construed as specifically disclosing each of the two specified features or components, with or without the others. For example, "A and / or B" should be construed as specifically disclosing (i) A, (ii) B, and (iii) each of A and B as if each were individually set forth herein.

[0106] As used herein, "room pressure" is intended to mean the pressure of the environment surrounding the systems and devices of the present inventive concept. Positive pressure includes pressure greater than room pressure, or simply pressure greater than another pressure, e.g., a positive pressure differential across a fluid path component such as a valve. Negative pressure includes pressure less than room pressure, or pressure less than another pressure, e.g., a negative pressure differential across a fluid component path such as a valve. Negative pressure may include a vacuum, but does not refer to a pressure less than a vacuum. As used herein, "vacuum" may refer to a full or partial vacuum, or any of the negative pressures described above.

[0107] When "diameter" is used herein to describe a non-circular shape, it should be interpreted as the diameter of an imaginary circle that approximates the described shape. For example, when describing a cross-section, such as a cross-section of a component, "diameter" shall be interpreted as representing the diameter of an imaginary circle having the same cross-sectional area as the cross-section of the described component. A shaft within the inventive concept, e.g., a hollow shaft comprising a lumen and a wall, has an inner diameter (ID) equal to the diameter of the lumen and an outer diameter (OD) defined by the outer surface of the shaft.

[0108] As used herein, the "major axis" and "minor axis" of a component are the length and diameter, respectively, of an imaginary cylinder of smallest volume that can completely enclose the component.

[0109] As used herein, a "transducer" should be interpreted to include any component (or combination of components) that receives energy or any input and produces an output. For example, a transducer may include an electrode that receives electrical energy and distributes the electrical energy to tissue (e.g., based on the size of the electrode). In some configurations, the transducer converts an electrical signal into any output, such as light (e.g., a transducer including a light-emitting diode or a light bulb), sound (e.g., a transducer including a piezoelectric crystal configured to transmit ultrasound energy), pressure, thermal energy, cryogenic energy, chemical energy, mechanical energy (e.g., a transducer including a motor or solenoid), magnetic energy, and / or another electrical signal (e.g., a Bluetooth or other wireless communication element). Alternatively, or in addition, the transducer may convert a physical quantity (e.g., a change in a physical quantity) into an electrical signal. The transducer may include any component that delivers energy and / or agents to tissue, such as a transducer configured to transmit one or more of electrical energy to tissue (e.g., a transducer including one or more electrodes), optical energy to tissue (e.g., a transducer including a laser, a light emitting diode, and / or an optical component, in one example a lens or prism), mechanical energy to tissue (e.g., a transducer including a tissue manipulation element), acoustic energy to tissue (e.g., a transducer including a piezoelectric crystal), chemical energy, electromagnetic energy, magnetic energy, and combinations of one or more of these.

[0110] As used herein, a "patient site" refers to a location within a patient's body, for example, a location within a bodily passage such as a blood vessel (e.g., an artery or vein) or a portion of the digestive tract (e.g., the esophagus, stomach, or intestines), or the location of an organ. A "patient site" may also refer to a location within the spine, for example, a location within the epidural space or subarachnoid space of the spine. A patient site may include a location containing one or more of an aneurysm, a stenosis, a thrombus, and / or a graft.

[0111] As used herein, a "neural site" refers to a patient site proximate to the brain, e.g., a site located within the patient's neck, head, or brain. A neural site may include a location proximate to the brain, including one or more of an aneurysm, a stenosis, a thrombus, and / or a graft.

[0112] As used herein, "adjacent" is intended to include a location relatively close to, on, and / or within the referenced component (or other location).

[0113] As used herein, "transparent" and "optically transparent" refer to the property of a material that is relatively transparent (e.g., not opaque) to light transmitted and / or collected by one or more components of an imaging system or probe (e.g., for collecting image data of a patient site) within the concepts of the present invention.

[0114] It is understood that certain features of the inventive concepts, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the inventive concepts, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable subcombination. It is understood that all features recited in any claim (whether independent or dependent) may be combined in any given manner.

[0115] The present concepts encompass imaging systems including an imaging probe and one or more delivery devices, such as a delivery catheter and / or guidewire. The imaging probe may be configured to be positioned proximate a patient site to collect image data from the patient site (e.g., a neural site, a spinal site, and / or other sites as defined above). The imaging probe includes an elongate shaft having a lumen. In some embodiments, a rotatable optical core and a distally disposed optical assembly are disposed within the lumen of the probe shaft. A probe connector may be disposed at a proximal end of the elongate shaft, the connector surrounding at least a portion of the rotatable optical core (e.g., the proximal end of the rotatable optical core). The present concepts further include methods of introducing the imaging probe into a patient site, e.g., a neural site, using one or more delivery devices, such as a delivery catheter and / or guidewire. In some embodiments, the imaging probe is advanced through the delivery catheter toward the patient site without advancing along a guidewire.

[0116] In some embodiments, the imaging probe includes an inertial assembly configured to reduce variations in the rotational speed of the rotatable optical core, hi some embodiments, the imaging probe includes an impeller attached to the rotatable optical core and configured to resist rotation of the rotatable optical core, such as when the rotatable optical core is retracted.

[0117] In some embodiments, the imaging probe includes a reinforcement assembly embedded in the elongate shaft, which may be configured to resist bending of the elongate shaft and may have an optically transparent portion.

[0118] In some embodiments, the imaging probe includes an elongated shaft with a reduced inner diameter at least in part of the shaft, or a reduced gap between the elongated shaft and the rotatable optical core. The reduced gap may be configured to reduce fluctuations in the rotational speed of the rotatable optical core. In some embodiments, the reduced gap provides frictional engagement of the elongated shaft with the rotatable optical core, providing a damping force designed to reduce undesired speed fluctuations of the rotatable optical core (e.g., to avoid undesired fluctuations in the rotational speed of the attached optical assembly 130). Alternatively or additionally, a fluid may be disposed in the reduced gap (or elsewhere between the elongated shaft and the rotatable optical core), e.g., to reduce undesired speed fluctuations of the rotatable optical core. The fluid may include a shear-thinning fluid configured to avoid excessive loads on the rotatable optical core (e.g., to prevent breakage of the rotatable optical core during high-speed rotation).

[0119] Systems, devices, and methods of the present concepts may be used to diagnose and / or treat stroke. Stroke is the fourth leading cause of death in the United States, and associated disability costs lead all diseases. Stroke is caused by vascular disease and comes in two major forms: ischemic, in which the blood supply to the brain is interrupted, and hemorrhagic, in which a ruptured blood vessel causes blood to leak directly into brain tissue. Both forms have such high associated morbidity and mortality that improvements in diagnosis and treatment are expected to have a significant impact on healthcare costs.

[0120] Vascular imaging is the most important diagnostic tool when planning and administering treatments, such as thrombolytics or stent retrievers for clot removal (as in the treatment of ischemic stroke) or coils, flow diverters, and other devices for aneurysm repair (as in the treatment of hemorrhagic stroke). External, noninvasive imaging techniques (e.g., X-rays, angiograms, or MRIs) are the primary imaging modalities used, but these techniques provide limited information, such as vessel size and shape, at moderate resolution (e.g., approximately 200 μm). This level of resolution does not allow imaging of important perforator vessels (small vessels) present within the vasculature. The inability to adequately image these vessels limits preoperative planning as well as the immediate evaluation of treatment outcomes. The effectiveness of these imaging techniques is further limited by the shadows that may be created by the treatment itself (e.g., when implanting one or more coils) and local image fading. Therefore, intravascular imaging is desirable to examine the detailed morphology of the vessel wall and / or to better plan and evaluate the results of catheter-based interventions. Currently, intravascular imaging techniques, such as intravascular ultrasound (IVUS) and intravascular optical coherence tomography (OCT), have been developed but are only approved for use in coronary arteries. IVUS is also used in larger peripheral vasculature. Currently, intravascular imaging has not been expanded for use in neurovasculature, apart from the large carotid artery. The limitations of current techniques relate to the very small size of neurovasculature, approximately 1 mm in diameter or less, and the very high degree of tortuosity of the vessels (e.g., when attempting to navigate the tortuous carotid sinus to reach and image the middle cranial artery and its branches and portions).

[0121] Ultrasound has fundamental limitations in resolution and unavoidable beam divergence, especially when using small transducers, making optical techniques more suitable. With the advent of new light sources, such as broadband SLED light sources, visible wavelength laser diodes, and compact swept-frequency light sources (all of which are compatible with single-mode fiber and interferometric imaging techniques, such as OCT), the use of optical techniques is highly beneficial from both a clinical and commercial perspective. The use of single-mode fiber allows for small-diameter imaging catheters.

[0122] Referring to FIG. 1 , a schematic diagram of an imaging system including an imaging probe and one or more delivery devices is shown consistent with the concepts of the present invention. The system 10 is configured and designed to collect image data and generate an image based on the recorded data. By way of example, the system 10 may comprise an optical coherence tomography (OCT) imaging system. The system 10 includes an imaging probe 100 and at least one delivery device, such as at least one delivery catheter 50 and / or at least one guidewire 60. The system 10 may further include a console 200, which is an imaging console configured to be operably attached to the imaging probe 100. The system 10 may further include a fluid injector, such as injector 300 configured to inject one or more fluids, e.g., irrigation fluid, imaging contrast agent (e.g., radiopaque contrast agent, hereinafter referred to as “contrast agent”), and / or other fluids, e.g., the illustrated injectate 305. The system 10 may further include an implant, e.g., implant 85, implanted into the patient's body by implant delivery device 80. System 10 may further include a treatment device 91 configured to treat the patient, which may be configured to dilate a stenosis, remove stenotic material (e.g., a thrombus), and / or treat a disease or disorder in the patient. System 10 may further include a second imaging device, such as imaging device 92 as shown.

[0123] Imaging probe 100 includes an elongated shaft 110 having a proximal end 111, a distal end 119, a proximal section 111a, an intermediate section (central section 115), and a distal section 119a. An optical connector 102, e.g., a connector configured to operably attach probe 100 to console 200, is disposed on proximal end 111 of shaft 110. Imaging probe 100 is configured to provide patient images, such as three-dimensional (3D) images, generated upon retraction of shaft 110 of imaging probe 100. In some embodiments, imaging probe 100 and / or other components of system 10 have a similar configuration and design to similar components described in applicant's co-pending U.S. Provisional Patent Application No. 62 / 148,355, filed April 29, 2015, entitled "Micro-Optic Probes for Neurology," the contents of which are incorporated herein in their entirety for all purposes.

[0124] The imaging system 10 may include one or more imaging probes 100, each suitable for imaging highly tortuous body lumens (e.g., the middle cranial artery, various peripheral arteries, and ducts of the endocrine system, such as the hepatic duct (bile duct) and pancreatic duct). Each imaging probe 100 may have a very small cross-section, typically less than 1 mm in OD, and contains a rotatable optical core 120, which includes a single fiber optically connected at its distal end to an optical assembly 130. The core 120 rotates to generate high-fidelity images of the lumen wall within which the probe 100 is inserted. The imaging probe 100 and other components of the imaging system 10 may be configured to facilitate a uniform rotational speed of the core 120 while the imaging probe 100 traverses difficult anatomy. The imaging system 10 may include multiple imaging probes 100 provided in a kit configuration, e.g., two or more probes 100 having different characteristics (e.g., different lengths, diameters, and / or flexibility).

[0125] The imaging probe 100 is configured and designed to collect image data from a patient site. The distal portion 119a may be configured to pass through a patient site (e.g., a patient site containing occlusive material, such as a thrombus, or a patient site containing an implant). In some embodiments, the probe 100 is configured to collect image data from a neural site (e.g., a neural site selected from the group consisting of an artery in the patient's neck, an artery in the patient's neck, an artery in the patient's head, a vein in the patient's head, an artery in the patient's brain, a vein in the patient's brain, and one or more combinations thereof). In some embodiments, the probe 100 is configured and designed to collect image data from one or more locations along or proximate to the patient's spine. In some embodiments, probe 100 is configured and designed to collect image data from tissue selected from the group consisting of wall tissue of a blood vessel at the patient site, a thrombus proximate the patient site, an occlusion proximate the patient site, a blood vessel outside the blood vessel in which optical assembly 130 is positioned, tissue outside the blood vessel in which optical assembly 130 is positioned, extracellular deposits outside the lumen of the blood vessel in which optical assembly 130 is positioned (e.g., within and / or outside the blood vessel wall), and combinations of one or more of these. Alternatively, or in addition, optical assembly 130 may be configured and designed to collect image data from an implanted device (e.g., a temporarily or chronically implanted device), such as implant 85 described below, or a device previously implanted within the patient's body. In some embodiments, optical assembly 130 is configured and designed to collect image data related to a placement procedure in which an implant is placed within a patient (e.g., real-time data collected during placement).The optical assembly 130 may be configured and designed to collect implant data, including position and / or expansion data, related to the placement of an implant or other treatment device (e.g., a device selected from the group consisting of a stent retriever (also known as a stentriver), an embolic device such as an embolic coil, an embolic coil delivery catheter, an occlusion device, a stent, a covered stent, a stent delivery device, a flow diverter, an aneurysm treatment device, an aneurysm delivery device, a balloon catheter, and one or more combinations thereof). In some embodiments, the optical assembly 130 is configured and designed to collect data related to the position of the implant 85 or other device including a stimulation element, for example, an electrode or other stimulation electrode positioned proximate to the brain (e.g., an electrode positioned deep in the brain or at other brain locations), or a stimulation element positioned proximate to the spine (e.g., a stimulation element configured to treat pain by stimulating spinal tissue). The implantation of the implant 85 may be performed based on an analysis of the collected image data (e.g., analysis of the collected image data by the algorithm 240). This analysis may be used to modify implant parameters selected from the group consisting of: selection of an implantable device (e.g., selection of implant 85), selection of porosity of an implantable device, selection of metal coverage of an implantable device, selection of pore density of an implantable device, selection of diameter of an implantable device, selection of length of an implantable device, selection of location for implanting an implantable device, expansion parameters for expanding an implantable device once implanted, repositioning an implantable device once implanted, selection of a second implantable device to be implanted, and combinations thereof. Adjustments to the implantation may be made based on one or more issues identified in the analysis (e.g., issues selected from the group consisting of malpositioning of an implantable device, insufficient deployment of an implantable device, presence of air bubbles, and combinations thereof).

[0126] In some embodiments, optical assembly 130 is configured and designed to collect data regarding the position of a treatment device (eg, treatment device 91 described below) during a patient treatment procedure.

[0127] The delivery catheter 50 may include one or more delivery catheters (e.g., delivery catheters 50a, 50b, 50c-50n shown in the figures). The delivery catheter 50 may include a vascular introducer. For example, the delivery catheter 50a shown in FIG. 1 is a delivery catheter 50 that is a vascular introducer. INTRO Other delivery catheters 50 include a vascular introducer that is inserted into the delivery catheter 50 after the vascular introducer is placed through the patient's skin. INTRO The two or more delivery catheters 50 may be inserted into a patient's body through a pair of inner diameters (ID) and outer diameters (OD) such that a first delivery catheter 50 slidingly receives a second delivery catheter 50 (e.g., the OD of the second delivery catheter is equal to or less than the ID of the first delivery catheter) and a second delivery catheter 50 slidingly receives a third delivery catheter 50 (e.g., the OD of the third delivery catheter is equal to or less than the ID of the second delivery catheter). In these configurations, delivery catheters 50 of successively smaller diameters may be used to advance a first delivery catheter 50 to a first anatomical location, advance a second delivery catheter 50 to a second anatomical location distal or remote (hereinafter "distal") from the first anatomical location, and so forth, as appropriate.

[0128] Each delivery catheter 50 includes a shaft 51 (e.g., shafts 51a, 51b, 51c, and 51n as shown) having a respective distal end 59 (e.g., distal ends 59a, 59b, 59c, and 59n as shown). A connector 55 (e.g., connectors 55a, 55b, 55c, and 55n as shown) is disposed at the proximal end of each shaft 51. Each connector 55 may include a Touhy connector or other valved connector, for example, a valved connector (with or without a separate shaft disposed within connector 55) configured to prevent the exit of fluid from the associated catheter 50. Each connector 55 may include a port 54, as shown on delivery catheters 50b, 50c, and 50n, for example, a port configured and designed to allow the introduction of fluid into and / or the removal of fluid from the associated delivery catheter 50. In some embodiments, irrigation fluid, as described below, is introduced through one or more ports 54, for example, to remove blood or other undesirable material from adjacent to optical assembly 130. Ports 54 may be located on the sides of connector 55 and may include a Luer fitting and a cap and / or valve. Shaft 51, connector 55, and ports 54 may each comprise standard materials and may have configurations similar to commercially available introducers, guide catheters, diagnostic catheters, mid-catheters, and microcatheters used in interventional procedures.

[0129] Each delivery catheter 50 has a lumen 52 (reference number 52 is shown on delivery catheter 50a but has been removed from the remaining delivery catheters 50 for clarity) extending from connector 55 to the distal end 59 of shaft 51. The diameter of each lumen 52 defines the ID of the associated delivery catheter 50. Each delivery catheter 50 may be advanced over a guidewire (e.g., guidewire 60) through lumen 52. In some embodiments, delivery catheter 50 is configured for rapid exchange advancement and retraction over a guidewire, for example, via a sidecar having a rapid exchange (Rx) guidewire lumen as known to those skilled in the art. In some embodiments, the probe 100 and at least one delivery catheter 50 are cooperatively configured and designed such that the delivery catheter 50 is advanced through a vessel, such as a blood vessel, and the probe 100 is slidingly received by the delivery catheter 50 and advanced through the delivery catheter 50 to a location proximate the patient region PS to be imaged (e.g., a location just distal to, within, and / or immediately adjacent to the patient region PS to be imaged). In some embodiments, a second delivery catheter 50 is slidingly received by a first delivery catheter 50, and the probe 100 is advanced through the second delivery catheter 50 to a location proximate the patient region PS to be imaged. In still other embodiments, three or more delivery catheters 50 are coaxially inserted within one another, and the probe 100 is advanced through the innermost delivery catheter 50 to a location proximate the patient region PS to be imaged. In some embodiments, the probe 100 is advanced through (e.g., through) one or more delivery catheters 50 without the use of a guidewire.

[0130] The delivery catheter 50 may include one or more delivery catheters selected from the group consisting of an introducer, a vascular introducer, an introducer having an ID of 7 Fr to 9 Fr, a delivery catheter (also referred to as a guide catheter) that is placed through the aortic arch (e.g., its distal end just distal to or proximal to the aortic arch), such as a delivery catheter having an ID of 5 Fr to 7 Fr or about 6.5 Fr, a delivery catheter (also referred to as an intermediate catheter) that is inserted into a larger pre-placed delivery catheter, such as an intermediate delivery catheter having an ID of 0.053 inches to 0.070 inches, a delivery catheter (also referred to as a microcatheter) having an ID of 0.0165 inches to 0.027 inches, and a combination of one or more of these. In some embodiments, the delivery catheter 50 includes a first delivery catheter 50 that includes an introducer (e.g., an introducer having an ID of 7 Fr to 9 Fr or about 8 Fr). INTRO The delivery catheter 50 further includes a second delivery catheter 50 configured and designed to be inserted into the first delivery catheter 50 (e.g., a second delivery catheter 50 configured and designed for placement through the aortic arch and having an ID of 5 Fr or more and 7 Fr or less, or about 6 Fr). GUIDE The delivery catheter 50 may include a first delivery catheter 50 INTRO and / or a second delivery catheter 50 GUIDE a third delivery catheter 50 configured and designed to be inserted into the third delivery catheter 50, e.g., a third delivery catheter 50 having an ID of 0.053 inches or greater and 0.070 inches or less; INTER The delivery catheters 50 may include a fourth delivery catheter 50 configured and designed to be inserted into the first, second, and / or third delivery catheters 50. MICRO , for example, a fourth delivery catheter 50 having an ID of 0.0165 inches or greater and 0.027 inches or less. MICROThe imaging probe 100 may be configured and designed to be inserted into the first, second, third, and / or fourth delivery catheters 50, for example, where the OD of the imaging probe 100 is less than 0.070 inches, such as where the OD of at least a distal portion of the imaging probe 100 is 0.025 inches or less, 0.022 inches or less, 0.018 inches or less, 0.016 inches or less, 0.015 inches or less, or 0.014 inches or less. In some embodiments, the ID of at least a distal portion of the imaging probe 100 is about 0.014 inches (e.g., 0.012 inches or more and 0.016 inches or less). In some embodiments, the system 10 includes the probe 100 and one or more delivery catheters 50.

[0131] Each delivery catheter 50 may have an optically transparent portion (e.g., a portion relatively transparent to light transmitted and / or received by the optical assembly 130, such as the transparent portion 57 shown on delivery catheter 50n and described herein). The length of the transparent portion 57 may be 50 cm or less (e.g., from 1 cm to 15 cm, or from 2 cm to 5 cm). The transparent portion 57 may be part of a delivery catheter 50 that includes a microcatheter having an ID of from 0.0165 inches to 0.027 inches, or from 0.021 inches to 0.027 inches. The system 10 may include a first delivery catheter 50 that slidingly receives the probe 100 and has the transparent portion 57, and a second delivery catheter 50 that slidingly receives the first delivery catheter 50.

[0132] Each delivery catheter 50 may include a spring tip (eg, spring tip 104, not shown but described herein as being attached to shaft 110 of probe 100).

[0133] Guidewire 60 may include one or more guidewires (e.g., illustrated guidewires 60a, 60b-60n) configured and designed to assist in advancing (e.g., intravascularly) probe 100 and / or delivery catheter 50 (e.g., through a rapid exchange lumen in distal portion 119a of shaft 110) to a patient site PS, such as a neural site. The guidewire 60 may be a guidewire having an OD of 0.035 inches to 0.038 inches, a guidewire having an OD of 0.010 inches to 0.018 inches, a reach-length guidewire, for example a guidewire having a length of about 200 cm, an exchange-length guidewire, for example a guidewire having a length of about 300 cm, a guidewire having a length of 175 cm to 190 cm, a guidewire having a length of 200 cm to 300 cm and an OD of 0.014 inches to 0.016 inches, a hydrophilic guidewire, a Stryker Synchro™ guidewire, a Terumo guidewire, for example a Terumo Glidewire™ guidewire, a Terumo The guidewires may include one or more guidewires selected from the group consisting of Traxcess™ guidewires, X-Celerator™ guidewires, X-Pedion™ guidewires, Agility™ guidewires, Bentson™ guidewires, Coon™ guidewires, Amplatz™ guidewires, and combinations of one or more of the foregoing. In some embodiments, system 10 includes probe 100 and one or more guidewires 60. Guidewire 60 may include one or more visualization portions, for example, one or more radiopaque or ultrasound reflective portions.

[0134] The system 10 may include delivery catheters 50 and guidewires 60 in various pairs and configurations. In some embodiments, the delivery catheters 50 include a first delivery catheter 50 that includes an introducer (e.g., a vascular introducer). INTRO and a delivery catheter 50 INTROand at least two delivery catheters 50 inserted into the delivery catheter 50, the catheters having different pairs of corresponding IDs and ODs to allow for sequential insertion of each delivery catheter 50, for example, through the lumen 52 of a previously placed delivery catheter 50. In some embodiments, a first delivery catheter 50 is advanced along a first guidewire 60, after which (e.g., after removing the first guidewire 60 from the first delivery catheter 50 and replacing it with a second guidewire 60) a smaller OD delivery catheter 50 is advanced along the smaller OD guidewire 60. In some embodiments, after image data is collected with an imaging probe 100 placed within the delivery catheter (e.g., after retraction to collect image data), the imaging probe 100 is removed and replaced with a guidewire 60 over which additional devices (e.g., another delivery catheter 50, a treatment device 91, a graft delivery device 80, or other devices) can be placed. In some embodiments, the insertion, advancement and / or retraction of the probe 100, one or more delivery catheters 50 and / or one or more guidewires 60 is performed as described herein.

[0135] The probe 100, one or more delivery catheters 50, and / or one or more guidewires 60 may be advanced to the patient site PS through one or more blood vessels (e.g., more delivery catheters 50 may be advanced along a guidewire 60 through one or more arteries or veins). Alternatively, or in addition, the probe 100, one or more delivery catheters 50, and / or one or more guidewires 60 may be advanced to the patient site PS through a non-vascular lumen (e.g., the epidural space and / or subarachnoid space of the spine) or through another body cavity or space (e.g., the entire guidewire 60 may be advanced).

[0136] In some embodiments, one or more delivery catheters 50 include functional elements 53 (e.g., functional elements 53a, 53b, 53c, and 53n as shown). Each functional element 53 may include one or more functional elements, such as one or more sensors, transducers, and / or other functional elements, as described in more detail below. In some embodiments, the length of shaft 110 is 100 cm or more, 200 cm or more, or 240 cm or more. In some embodiments, the length of shaft 110 is about 250 cm. In some embodiments, the length of shaft 110 is 350 cm or less, 250 cm or less, or 220 cm or less.

[0137] In some embodiments, shaft 110 has an outer diameter (OD) of 0.005 inches or more and 0.022 inches or less along at least a portion of its length (e.g., at least a portion of distal portion 119a). In some embodiments, shaft 110 has an OD of about 0.0134 inches, an OD of 0.014 inches or less, or an OD of 0.016 inches or less along at least a portion of its length (e.g., along the portion surrounding core 120 and / or optical assembly 130 and / or along at least the most distal 10 cm, 20 cm, or 30 cm of shaft 110). In these embodiments, imaging probe 100 may be configured to be advanced and / or retracted without a guidewire or delivery catheter (e.g., when advancing and / or retracting optical assembly 130 and shaft 110 together during image data acquisition). In some embodiments, the OD of shaft 110 is less than 1 mm or less than 500 μm along at least a portion of its length. In some embodiments, the OD of shaft 110 varies along its length. In some embodiments, the OD of distal portion 119a is larger than the OD of central portion 115, e.g., the OD of the portion of distal portion 119a surrounding optical assembly 130 is larger than the OD of central portion 115. In these embodiments, the ID of distal portion 119a can be similar to or larger than the ID of central portion 115.

[0138] In some embodiments, shaft 110 has an inner diameter (ID) of 0.004 inches or more and 0.012 inches or less along at least a portion of its length. In some embodiments, shaft 110 has an ID of about 0.0074 inches along at least a portion of its length (e.g., along the portion surrounding core 120 and / or optical assembly 130). In some embodiments, the ID of shaft 110 varies along its length. In some embodiments, the ID of distal portion 119a is larger than the ID of central portion 115, e.g., the ID of the portion of distal portion 119a surrounding optical assembly 130 is larger than the ID of central portion 115.

[0139] In some embodiments, shaft 110 has a wall thickness along at least a portion of its length (e.g., along the portion surrounding core 120 and / or optical assembly 130) of at least 0.001 inch and no more than 0.005 inch, or a wall thickness of about 0.003 inch. In some embodiments, shaft 110 includes a thinner wall (e.g., thinner than the portion of the wall surrounding core 120) that surrounds at least a portion of optical assembly 130.

[0140] In some embodiments, the ID of the distal portion 119a of the shaft 110 is larger than the ID of the central portion 115 of the shaft 110. For example, the ID of the central portion 115 is 0.002 inches or more larger than the ID of the distal portion 119a. In these embodiments, the OD of the central portion 115 and the OD of the distal portion 119a may be similar. Alternatively, the OD of the middle portion 115 may be different from the OD of the distal portion 119a (e.g., the OD of the distal portion 119a may be larger than the OD of the middle portion 115, e.g., by 0.001 inches or more for the distal portion 119a).

[0141] In some embodiments, the imaging probe 100 has a stiffened portion, for example, if the imaging probe 100 includes a stiffening element 118. The stiffening element 118 is disposed in, within, and / or along at least a portion of the shaft 110. In some embodiments, the stiffening element 118 is disposed in or on an inner surface of a wall of the shaft 110. In some embodiments, the stiffening element 118 includes a wire wrapped around the core 120. In some embodiments, the stiffening element 118 terminates proximal to the optical assembly 130. Alternatively, the stiffening element 118 may move laterally and / or beyond the optical assembly 130, for example, a portion of the stiffening element 118 includes one or more optically transparent materials.

[0142] In some embodiments, the wall thickness of distal portion 119a is less than the wall thickness of central portion 115. In some embodiments, distal portion 119a comprises a material that is stiffer than the material of central portion 115 and / or distal portion 119a includes a stiffening element (e.g., stiffening element 118a shown in FIG. 13 below), e.g., when the wall thickness of distal portion 119a is less than the wall thickness of central portion 115.

[0143] In some embodiments, the probe 100 includes a guidewire lumen (e.g., a rapid exchange guidewire lumen disposed in a sidecar 105 shown in FIG. 1). The length of the sidecar 105 can be less than 150 mm. The length of the sidecar 105 can be 15 mm or more (e.g., about 25 mm).

[0144] In some embodiments, the proximal portion 111a of the shaft 110 is arranged in a service loop. The proximal portion 111a of the shaft 110 may include a different configuration than the central portion 115 or a different configuration than the distal portion 119a. The proximal portion 111a may have a larger OD or thicker walls than the central portion 115.

[0145] In some embodiments, shaft 110 includes an outer shaft and an inner "torque" shaft that is shorter than the outer shaft, as described below with reference to Figure 14. In some embodiments, the torque shaft terminates before the portion of probe 100 that enters the patient's body.

[0146] In some embodiments, the system 10 includes a torque tool 320, which is a tool that frictionally engages the shaft 110 of the probe 100 (e.g., laterally at a position along the proximal portion 111a), allowing the operator to apply a torsional force to the shaft 110.

[0147] 1A, an enlarged view of distal portion 119a is shown, consistent with the concepts of the present invention. Lumen 112 extends from proximal end 111 of shaft 110 to distal portion 119a, terminating at a location proximal to distal end 119a. Disposed within lumen 112 is core 120, a rotatable optical core. Disposed at the distal end of core 120 is optical assembly 130, an optical assembly. Optical assembly 130 includes lens 131 and reflector 132, a reflective surface. Optical assembly 130 is disposed within viewing portion 117, a window portion of shaft 110 that is optically translucent and / or effectively transparent. Optical assembly 130 is configured and designed to collect image data through at least a portion of shaft 110. In some embodiments, optical assembly 130 is further configured and designed to collect image data through at least a portion of an additional device, in one example, at least a portion of the shaft of delivery catheter 50 (e.g., an optically transparent portion of delivery catheter 50, such as transparent portion 57 described herein). In Figure 1A, optional components sidecar 105 and stiffening element 118 have been removed for clarity.

[0148] In some embodiments, a fluid 190 is disposed within lumen 112 (e.g., the space not occupied by core 120 and optical assembly 130) (e.g., fluids 190a and 190b shown in FIG. 1A , where fluid 190b is disposed around optical assembly 130 and fluid 190a is disposed around core 120 proximal to optical assembly 130). Fluid 190 (e.g., fluid 190b) may comprise an optically transparent fluid. In some embodiments, fluid 190a and fluid 190b comprise similar materials. Alternatively, or in addition, fluid 190a and fluid 190b may comprise dissimilar materials. In some embodiments, fluid 190a comprises a fluid that is more viscous than fluid 190b. Fluids 190a and / or 190b (alone or collectively, fluid 190) may be configured and designed to limit undesirable fluctuations in the rotational speed of core 120 and / or optical assembly 130. In some embodiments, fluid 190 includes a gel. In some embodiments, fluid 190 includes a non-Newtonian fluid (e.g., a shear-thinning fluid) or other fluid whose viscosity changes with shear. Alternatively, or in addition, fluid 190 may include a lubricant (e.g., to provide lubrication between core 120 and shaft 110). In some embodiments, fluid 190 includes a shear-thinning fluid, and core 120 rotates at speeds greater than 50 Hz (e.g., greater than 100 Hz or 200 Hz). If fluid 190 includes a high-viscosity Newtonian fluid at higher rotational speeds, the resulting viscous drag during core 120 rotation would impose torsional loads on core 120, causing core 120 to fail before reaching high rotational speeds. However, fluid 190 including a low-viscosity Newtonian fluid is also undesirable because it may not provide sufficient damping (e.g., adequate rotational speed control), for example, during low-speed (“idle mode”) imaging. For these reasons, the probe 100 may contain a fluid 190 that is a relatively high viscosity, shear-thinning (non-Newtonian) fluid that provides sufficient load during slow rotation of the core 120 and avoids excessive load during high rotation of the core 120 due to its changing viscosity.In some embodiments, the fluid 190 comprises a shear-thinning fluid whose viscosity varies nonlinearly (e.g., its viscosity decreases rapidly with increasing shear rate). In some embodiments, the probe 100 has a gap formed between the shaft 110 and the core 120 that is reduced along at least a portion of the shaft 110 (e.g., the portion of the shaft 110 proximal to the optical assembly 130) by, for example, a space reduction element as described below with reference to FIG. 16 . The gap may be between 20 μm and 200 μm (e.g., a gap that is constant or varies between 20 μm and 200 μm). The fluid 190 (e.g., a high-viscosity shear-thinning fluid) may be disposed in (at least) the portion of the shaft 110 where the gap is reduced. In this configuration, the amount of force applied to the core 120 to reduce rotational fluctuations is proportional to the shear stress and the length of the shaft 110 over which the fluid 190 and the shaft 110 interact (the “interaction length”). Locating this interaction length relatively close to the optical assembly 130 optimizes the reduction of undesirable rotational speed fluctuations of the optical assembly 130 (e.g., the core 120 may have low torsional stiffness, so braking it far enough away from the optical assembly 130 does not have the desired effect on the optical assembly 130).

[0149] In some embodiments, the optical assembly 130 includes a lens 131 with an OD larger than the diameter of the lumen 112 of the shaft 110 (e.g., larger than the diameter of at least a portion of the lumen 112 proximal to the optical assembly 130). The OD of the lens 131, which is larger than the diameter of the lumen 112, prevents the optical assembly 130 from translating within the lumen 112. For example, the lens 131 may include a relatively large aperture lens (e.g., a lens 131 with an OD approaching 350 μm), e.g., to provide a small spot size while collecting a large amount of light. Relative to this diameter, the lumen 112 may be smaller (e.g., less than 350 μm) to enable the small OD of the shaft 110 proximal to the optical assembly 130 (e.g., as shown in FIGS. 4, 5, 6, 12, 13, and 16). In embodiments in which the OD of the optical assembly 130 is larger than the diameter of the lumen 112 at a location proximal to the optical assembly 130, the portion of the shaft 110 surrounding the optical assembly 130 has a larger OD and / or ID than the portion of the shaft 110 proximal to the optical assembly 130. In these embodiments, both the shaft 110 and the optical assembly 130 are retracted simultaneously during image data acquisition because the diameter of the lumen 112 is too small to allow for translational movement of the optical assembly 130.

[0150] In some embodiments, fluid 190 (e.g., fluid 190a) comprises a fluid having a viscosity of 10 Pa·S or more and 100,000 Pa·S or less. In these embodiments, fluid 190 has a viscosity of about 100 s -1The fluid 190 may be configured to have a viscosity that drops to about 3 Pa·S at a shear rate of 100 Pa·S or more, e.g., about 10 Pa·S. In some embodiments, the viscosity of the fluid 190 (e.g., fluid 190b) is between 1 Pa·S and 100 Pa·S or less, e.g., about 10 Pa·S. In some embodiments, the fluid 190 is configured to tend to center the core 120 within the lumen 112 of the shaft 110 as the core 120 rotates (e.g., due to the shear thinning properties of the fluid 190). In some embodiments, the fluid 190a comprises a hydrocarbon-based material and / or silicone. In some embodiments, the fluid 190b comprises a mineral oil and / or silicone. In some embodiments, the probe 100 includes one or more fluids 190 within at least the distal-most 20 cm of the shaft 110.

[0151] In some embodiments, lumen 112 includes a sealant, which is a sealing element 116 configured and designed to provide a seal between core 120 and the wall of shaft 110 (e.g., when disposed within distal portion 119a). Sealing element 116 allows core 120 to rotate while preventing mixing and / or movement of fluids 190a and / or 190b (e.g., by resisting flow of either around sealing element 116). In some embodiments, sealing element 116 is positioned between 1 mm and 200 mm from optical assembly 130, e.g., approximately 3 mm from optical assembly 130. In some embodiments, sealing element 116 includes two or more sealing elements, e.g., two or more sealing elements 116 that slidingly engage core 120 and / or optical assembly 130. In some embodiments, the probe 100 includes a sealing element disposed in the proximal portion of the shaft 110 (e.g., in or near the connector 102), such as sealing element 151 described below with reference to FIG. 7.

[0152] The sealing element 116 and / or 151 may include a hydrogel material, a conformable material, a silicone, and combinations of one or more of these. In some embodiments, the sealing element 116 and / or 151 is bonded to the shaft 110 with an adhesive or is simply an adhesive on the shaft 110 (e.g., a UV-curable adhesive or an adhesive configured not to bond with the core 120).

[0153] In some embodiments, fluid 190 is pressurized, for example, as described herein with reference to FIG. 7, for example, to mitigate bubble formation and / or bubble growth within fluid 190.

[0154] Shaft 110 may comprise one or more materials and may include at least a portion that is braided and / or includes one or more backing materials (e.g., a polyimide or PTFE backing). In some embodiments, at least the distal portion 119a of shaft 110 has an OD of 0.025 inches or less (e.g., 0.022 inches or less, 0.018 inches or less, 0.016 inches or less, 0.015 inches or less, or 0.014 inches or less). In some embodiments, shaft 110 includes a material selected from the group consisting of polyetheretherketone (PEEK), polyimide, nylon, fluorinated ethylene propylene (FEP), polytetrafluoroethylene (PTFE), polyether block amide (Pebax), and combinations of one or more of the foregoing. In some embodiments, shaft 110 includes at least a portion that includes a braid including stainless steel and / or a nickel-titanium alloy, such as a shaft 110 including a braid disposed over a thin-walled FEP or PTF. The braided portion may be coated with Pebax or other flexible material. In some embodiments, the shaft 110 includes at least a portion (e.g., a proximal portion) that is metal, such as a metallic hypotube including stainless steel and / or a nickel-titanium alloy. In some embodiments, the shaft 110 has a first portion that is a metal tube and a second portion distal to the first portion that includes a braided shaft. In some embodiments, the shaft 110 includes at least a portion that includes a hydrophobic material or other material configured to reduce change (e.g., change in length) when exposed to a fluid.

[0155] The viewing portion 117 of the shaft 110 may comprise one or more materials, and may comprise materials similar to or different from other portions of the shaft 110. The ID and / or OD of the viewing portion 117 may be similar to one or more other portions of the shaft 110. In some embodiments, the ID and / or OD of the viewing portion 117 is greater than the ID and / or OD of the shaft 110 at the central portion 115 of the shaft 110. The viewing portion 117 may have the same or different flexibility as one or more other portions of the shaft 110. The viewing portion 117 may comprise one or more optically transparent materials selected from the group consisting of Pebax, Pebax 7233, PEEK, amorphous PEEK, polyimide, glass, sapphire, nylon 12, nylon 66, and combinations of one or more of these.

[0156] In some embodiments, a flexible tip, such as the illustrated spring tip 104, is disposed at the distal end of the shaft 110. The length of the spring tip 104 can be between 0.5 cm and 5 cm (e.g., about 1 cm, about 2 cm, about 3 cm, or between 2 cm and 3 cm). At least a portion of the spring tip 104 can be made visible to imaging devices by including a radiopaque material (e.g., platinum or other material that is visible to X-ray imaging devices). The spring tip 104 can include a core including a material such as stainless steel.

[0157] In some embodiments, the probe 100 and / or other components of the system 10 include one or more markers (e.g., radiopaque markers or other visible markers), sensors, transducers, or other functional elements, such as functional elements 53a-n of the delivery catheter 50, functional element 83 of the graft delivery device 80, functional element 93 of the treatment device 91, functional elements 113a and 113b of the shaft 110 (singly or collectively, functional element 113, described below), functional element 123 of the core 120, functional element 133 of the optical assembly 130, functional element 203 of the console 200, and functional element 303 of the injector 300.

[0158] In some embodiments, the core 120 comprises a single-mode glass fiber (e.g., a fiber with an OD of 40 μm to 175 μm, a fiber with an OD of 80 μm to 125 μm, a fiber with an OD of 60 μm to 175 μm, or a fiber with an OD of about 110 μm). The core 120 may comprise a material selected from the group consisting of silica glass, plastic, polycarbonate, and combinations of one or more thereof. The core 120 may comprise a fiber having a coating, such as a polyimide coating. The core 120 may include a coating material and / or coating surrounding the fiber, for example, as known to those skilled in the art. The numerical aperture (NA) of the core 120 may be 0.11 or greater (e.g., about 0.16 or about 0.20). In some embodiments, the core 120 may have an NA (e.g., an NA of 0.16 to 0.20) that significantly reduces losses due to bends, such as those encountered in tortuous biological structures. System 10 may be configured to rotate core 120 in a single direction (unidirectional rotation) or multiple directions (bidirectional rotation).

[0159] In some embodiments, the probe 100 and other components of the system 10 are configured to retract the core 120 within the shaft 110. In these embodiments, the probe 100 may introduce a material (e.g., a fluid 190) into and within the shaft 110 (e.g., between the core 120 and the shaft 110). The introduced material may be configured to provide a function selected from the group consisting of refractive index matching, lubricity, bubble purging, and a combination of one or more of these.

[0160] In some embodiments, the OD of optical assembly 130 is between 80 μm and 500 μm (e.g., between 125 μm and about 150 μm). In some embodiments, the length of optical assembly 130 is between 200 μm and 3000 μm (e.g., about 1000 μm). Optical assembly 130 may include one or more lenses (e.g., lens 131 shown, which in one example may be a GRIN lens and / or a ball lens). Optical assembly 130 may have a GRIN lens with a focal length between 0.5 mm and 10.0 mm (e.g., about 2.0 mm). Optical assembly 130 may include one or more reflective elements (e.g., reflective element 132 shown).

[0161] In some embodiments, the optical assembly 130 includes a lens 131 and a reflective element 132 offset from the lens 131 by one or more connecting elements 137, as shown in FIG. 18 . The connecting element 137 may include a tube (e.g., heat shrink tubing) surrounding at least a portion of the lens 131 and the reflective element 132. The connecting element 137 may include one or more elements selected from the group consisting of a tube, a flexible tube, heat shrink, an optically transparent arm, and combinations of one or more thereof. The connecting element 137 may space the reflective element 132 from the lens 131 by a distance of 0.01 mm to 3.0 mm (e.g., a distance of 0.01 mm to 1.0 mm). The reflective element 132 may comprise a partial portion of a larger assembly that is cut or separated (e.g., isolated) from the larger assembly during the manufacturing process used to produce the optical assembly 130. Using a larger assembly can simplify handling during manufacturing. In some embodiments, the resulting reflective element 132 comprises a shape-optimized reflector. Reflective element 132 may include a wire portion (such as a gold wire). In these embodiments, lens 131 may include a GRIN lens (e.g., a lens having an OD of about 150 μm and / or a length of about 1000 μm). In some embodiments, lens 131 further includes a second lens (e.g., a coreless lens disposed proximally of and optically connected to the GRIN lens).

[0162] In some embodiments, the imaging probe 100 has a reduced diameter portion (e.g., a reduced outer diameter and / or inner diameter) along the shaft 110 proximal to the optical assembly 130, as shown, for example, in Figures 4, 5, 6, 12, 13, and 16. In these embodiments, the optical assembly 130 may have a larger OD (e.g., proximal to the optical assembly 130) than the lumen 112 of the shaft 110, for example, to provide a larger lens 131 that improves imaging capabilities. In some embodiments, the probe 100 includes a space-reducing element between the shaft 110 and the core 120, as described below with reference to element 122 in Figure 16. The functional elements 113 and / or 123 may include a space-reducing element (e.g., a protrusion from the shaft 110 and / or the core 120, respectively).

[0163] The console 200 may include an assembly that is a rotating assembly 210 configured and designed to rotate at least the core 120. The rotating assembly 210 may include one or more motors configured to generate rotation (e.g., a motor selected from the group consisting of a DC motor, an AC motor, a stepper motor, a synchronous motor, and combinations of one or more thereof). The console 200 may include an assembly that is a retracting assembly 220 configured and designed to retract at least the shaft 110. The retracting assembly 220 may include one or more motors or linear drive elements configured to generate retraction (e.g., a component selected from the group consisting of a DC motor, an AC motor, a stepper motor, a synchronous motor, a gear mechanism, a linear drive mechanism, a magnetic drive mechanism, a piston, a pneumatic drive mechanism, a hydraulic drive mechanism, and combinations of one or more thereof). The rotation assembly 210 and / or the retraction assembly 220 may have a configuration and design similar to that described in the applicant's co-pending U.S. Provisional Patent Application No. 62 / 148,355, filed April 29, 2015, entitled "Micro-Optic Probes for Neurology," the contents of which are incorporated herein in their entirety for all purposes.

[0164] Console 200 may include imaging assembly 230 configured to provide light to and collect light from optical assembly 130 (e.g., via core 120). Imaging assembly 230 may include light source 231. Light source 231 may include one or more light sources (e.g., one or more light sources configured to provide light of one or more wavelengths to optical assembly 130 via core 120). Light source 231 is configured to provide light to optical assembly 130 (via core 120) so as to collect image data including cross-sectional, longitudinal, and / or volumetric information about the patient part PS or implanted device being imaged. The light source 231 may be configured to provide light such that characteristics of tissue within the patient region PS being imaged are included in the collected image data, for example to quantify, assess, or provide information regarding a patient disease or disorder present within the patient region PS being imaged. The light source 231 may be configured to deliver broadband light and have a center wavelength ranging from 800 nm to 1700 nm. The bandwidth of the light source 231 may be selected to achieve a desired resolution and may vary depending on the needs of the intended application of the system 10. In some embodiments, the bandwidth is approximately 5% to 15% of the center wavelength, thereby achieving a resolution of 20 μm and 5 μm, respectively. The light source 231 may be configured to deliver light at a power level that meets ANSI Class 1 (“eye-safe”) limits, although higher power levels may be used. In some embodiments, the light source 231 delivers light in the 1.3 μm band at a power level of approximately 20 mW. As the center wavelength of the delivered light increases, light scattering by tissue is reduced, but absorption by water also increases. The light source 231 can deliver light at wavelengths closer to 1300 nm to offset these two effects. Light source 231 may be configured to transmit shorter wavelength light (e.g., about 800 nm light) across a patient region being imaged that contains a large amount of fluid. Alternatively, or in addition, light source 231 may be configured to transmit longer wavelength light (e.g., about 1700 nm light), for example, to reduce high levels of scattering within the patient region being imaged.

[0165] The imaging assembly 230 (or another component of the console 200) may include a fiber optic rotary joint (FORJ) configured to transmit light from the light source 231 to the core 120 and receive light from the core 120. In some embodiments, the core 120 includes a fiber having a first numerical aperture (NA), and the imaging assembly 230 includes an imaging assembly optical core having a second NA different from the first NA. For example, the first NA (the NA of the core 120) may have an NA of about 0.16, and the second NA (the NA of the imaging assembly optical core) may have an NA of about 0.11. In some embodiments, the system 10 includes an adapter 310 (e.g., a single-use or limited-use adapter used in fewer procedures compared to the imaging assembly 230) configured to optically connect the probe 100 to the imaging assembly 230. The adapter 310 may include a lens assembly configured to "optically match" (e.g., minimize coupling losses) different numerical apertures (e.g., the first and second NAs described above). In some embodiments, the adapter 310 includes a fiber having an NA that is the geometric mean of the two different NAs. In some embodiments, the adapter 310 includes a fiber having an NA that is the arithmetic mean of the two different NAs.

[0166] Rotating assembly 210 may be configured and designed to rotate core 120 (and subsequently one or more components of optical assembly 130) at a rotational speed of approximately 250 rps, or at a rotational speed of between 40 rps and 1000 rps. Rotating assembly 210 may be configured to rotate core 120 at a speed of between 20 rps and 2500 rps. In some embodiments, rotating assembly 210 may be configured to rotate core 120 at a speed of up to 25,000 rps. In some embodiments, the rotational speed provided by rotating assembly 210 is variable, e.g., the rotational speed is changed based on signals provided by sensors of system 10, e.g., when one or more functional elements 53, 83, 93, 113, 123, 133, 203, and / or 303 include sensors, and one or more signals from the one or more sensors are analyzed using algorithm 240. In some embodiments, the sensor signals represent the amount of light collected from tissue or other objects. In some embodiments, system 10 is configured to vary the rotational speed provided by rotating assembly 210 when the sensor signal correlates with a parameter selected from the group consisting of tortuosity of a blood vessel in which probe 100 is positioned, a stenosis of a blood vessel in which probe 100 is positioned, the presence of a blood clot proximate optical assembly 130, the presence of an implanted device proximate optical assembly 130, and combinations thereof. In some embodiments, the rotational speed provided by rotating assembly 210 is varied by an operator (e.g., a clinician) of system 10. Alternatively or additionally, system 10 can vary the rotational speed provided by rotating assembly 210 automatically or at least semi-automatically (herein "automatically"), including automatically varying the rotational speed as determined by one or more signals from one or more sensors described above. In some embodiments, rotation by rotating assembly 210 is increased (manually or automatically) as optical assembly 130 collects image data from the region of interest.

[0167] In some embodiments, the rotation assembly 210 is configured and designed to rotate the core 120 at one speed (e.g., greater than or equal to 150 rps or about 250 rps) during image data acquisition (i.e., during an “imaging mode”) and at another speed (e.g., a slower speed, e.g., greater than or equal to 30 rps and less than or equal to 150 rps) during a “preview mode.” During the preview mode, a “positioning maneuver” can be performed that can linearly position the optical assembly 130 and / or initiate a cleaning procedure. The positioning maneuver can be configured to visualize a bright reflection (e.g., due to one or more implants, e.g., an implanted stent, flow director, and / or coil). Alternatively, or in addition, the preview mode can be configured to prompt an operator (e.g., a clinician) to confirm that the optical assembly 130 has exited the distal end 59 of the surrounding delivery catheter 50. The preview mode may be configured to reduce the time and acceleration forces associated with rotating the core 120 at a speed that allows for image data collection (e.g., a rotational speed of 150 rps or greater or about 250 rps).

[0168] The retraction assembly 220 may be configured and designed to retract (e.g., by the core 120 and / or the retracting shaft 100) the optical assembly 130 at a retraction rate of about 40 mm / sec, for example, a retraction rate of 3 mm / sec to 500 mm / sec (e.g., 5 mm / sec to 60 mm / sec, or about 50 mm / sec). The retraction assembly 220 may be configured and designed to retract 20 mm to 150 mm (e.g., about 50 mm or about 75 mm) over a period of 0.1 seconds to 15.0 seconds, for example, over a period of 0.1 seconds to 10 seconds, or about 4 seconds. In some embodiments, the retraction distance and / or retraction rate may be selected by the operator and / or may be varied (e.g., manually or automatically). In some embodiments, the retraction distance and / or retraction rate provided by retraction assembly 220 is variable, e.g., the retraction distance and / or retraction rate is varied based on a signal provided by the sensor of system 10, for example, when one or more functional elements 53, 83, 93, 113, 133, 203, and / or 303 include a sensor and one or more signals from the one or more sensors are analyzed using algorithm 240. In some embodiments, the sensor signal represents the amount of light collected from tissue or other objects. In some embodiments, system 10 is configured to vary the retraction distance and / or retraction rate provided by retraction assembly 220 when the sensor signal correlates with a parameter selected from the group consisting of tortuosity of a blood vessel in which probe 100 is positioned, a stenosis of a blood vessel in which probe 100 is positioned, the presence of a blood clot proximate optical assembly 130, the presence of an implanted device proximate optical assembly 130, and combinations thereof. In some embodiments, the retraction distance and / or retraction rate provided by retraction assembly 220 is varied by an operator (e.g., a clinician) of system 10.Alternatively or additionally, system 10 may automatically or at least semi-automatically (herein "automatically") vary the retraction distance and / or retraction rate provided by retraction assembly 210, such as by automatically changing the retraction distance and / or retraction rate determined by one or more signals from one or more of the sensors described above. In some embodiments, the retraction distance and / or retraction rate provided by retraction assembly 220 is changed (increased or decreased, either manually or automatically) as optical assembly 130 collects image data from the region of interest.

[0169] In some embodiments, the retraction assembly 220 and the probe 100 are configured such that the retraction assembly 220 retracts the core 120 (e.g., the core 120 is retracted into the lumen 112 of the shaft 110) without causing translational movement of the shaft 110 during image data collection.

[0170] In some embodiments, the retraction assembly 220 and the probe 100 may be configured such that the retraction assembly 220 retracts the core 120 and the shaft 110 together during image data collection. In these embodiments, the shaft 110 may include a relatively short observation window 117 that surrounds the optical assembly 130 because the optical assembly 130 does not translate within the shaft 110. For example, in these embodiments, the length of the observation portion 117 may be 20 mm or less, 15 mm or less, 6 mm or less, or 4 mm or less. For example, the length of the observation portion 117 is about 3 mm. In some embodiments, the length of the observation portion 117 is 5 mm or more and 50 mm or less (e.g., about 10 mm or about 12 mm). In these embodiments in which the optical assembly 130 does not translate within the shaft 110, the diameter (ID and / or OD) of the shaft 110 can be reduced proximal to the viewing portion 117, e.g., the diameter (OD) of the shaft 110 (at least the portion of the shaft 110 surrounding and proximal to the optical assembly) can be 0.025 inches or less, 0.016 inches or less, or 0.014 inches or less. Alternatively, or in addition, in these embodiments in which the optical assembly 130 does not translate within the shaft 110, the portion of the shaft proximal to the optical assembly 130 (e.g., proximal to the viewing portion 117) can include a non-transparent structure, such as a braided structure or a structure using a material such as metal tubing (in one example, a hypotube made of nitinol or stainless steel), e.g., to improve the pushability of the probe 100.

[0171] Retraction assembly 220 may be configured to minimize the formation of bubbles in any fluid (e.g., fluid 190) within shaft 110, for example, by retracting shaft 110 and core 120 together or by retracting core 120 with a precision that avoids bubble formation. When retracting shaft 110, proximal portion 111 a may be positioned in a service loop. Retraction assembly 220 may include a translatable slide, and rotation assembly 210 may be disposed on the translatable slide.

[0172] The retraction assembly 220 may include a telescoping retraction assembly. The retraction assembly 220 may include a motor (e.g., a motor that is disposable or may be disposable, in one example, a disposable motor that is part of a telescoping retraction assembly).

[0173] In some embodiments, the rotating assembly 210 may be positioned independently with respect to the retraction assembly 220. In some embodiments, the retraction assembly 220 is positioned closer to the patient than the rotating assembly 210 (e.g., when the retraction assembly 220 is positioned within 20 cm of a vascular introducer or other patient introducer device into which the probe 100 is inserted). In some embodiments, the retraction assembly 220 is configured to be removably attached to the patient introducer device to connect with a Touhy connector of a vascular introducer into which the probe 100, such as a delivery catheter 50 described herein, is inserted.

[0174] In some embodiments, the retraction assembly 220 receives "motive power" from the console 200 via a drive shaft 211 that may be operably attached to the rotation assembly 210, for example as shown in FIG.

[0175] Console 200 may include a display 250, e.g., a display configured to provide one or more images (e.g., videos) based on the collected image data. Imaging assembly 230 may be configured to provide images on display 250 at an update frame rate of up to about 250 frames per second (e.g., comparable to the rotational speed of core 120). Display 250 may provide 2D and / or 3D representations of 2D and / or 3D data.

[0176] Console 200 may include one or more functional elements (e.g., functional element 203 shown in FIG. 1 ). Functional element 203 may include one or more functional elements (e.g., one or more sensors, transducers, and / or other functional elements, as described in more detail below).

[0177] Console 200 may include an algorithm (e.g., algorithm 240 as shown). The algorithm may be configured to adjust (e.g., automatically and / or semi-automatically adjust) one or more operating parameters of system 10 (e.g., operating parameters of console 200, probe 100, and / or delivery catheter 50). Alternatively, or in addition, algorithm 240 may be configured to adjust operating parameters of a separate device (e.g., injector 300 or graft delivery device 80, described below). In some embodiments, algorithm 240 is configured to adjust the operating parameters based on one or more sensor signals, such as sensor signals provided by sensor-based functional elements of the inventive concepts described herein (e.g., one or more of functional elements 53, 83, 93, 113, 123, 203, and / or 303). The algorithm 240 may be configured to adjust operating parameters selected from the group consisting of rotational parameters (e.g., rotational speed of the core 120 and / or the optical assembly 130), retraction parameters of the shaft 110 and / or the optical assembly 130 (e.g., retraction speed, distance, start position, end position, and / or retraction initiation timing (e.g., when to initiate retraction)), position parameters (e.g., position of the optical assembly 130), line spacing parameters (e.g., number of lines per frame), image display parameters (e.g., magnification adjustment of display size relative to vessel diameter), configuration parameters of the probe 100, parameters of the injectate 305 (e.g., ratio of saline to contrast agent configured to determine the appropriate refractive index), parameters of the light source 231 (e.g., transmit power and / or frequency of transmitted light), and combinations of one or more of these. In some embodiments, the algorithm 240 is configured to adjust retraction parameters (e.g., parameters that trigger the initiation of retraction).The retraction is initiated based on a parameter selected from the group consisting of, for example, lumen clearance, an injector 300 signal, a change in collected image data (e.g., a change in an image based on collected image data associated with proper evacuation of blood from around the optical assembly 130), and a combination of one or more of these. In some embodiments, the algorithm 240 is configured to adjust configuration parameters of the probe 100, for example, the algorithm 240 identifies the attached probe 100 (e.g., automatically via RF or other embedded ID) and adjusts parameters, such as arm path length and / or other parameters listed above.

[0178] The injector 300 may include a powered injector, syringe pump, peristaltic pump, or other fluid delivery device configured to inject contrast agents, such as radiopaque contrast agents, and / or other fluids. In some embodiments, the injector 300 is configured to deliver contrast agents and / or other fluids (e.g., contrast agent, saline, and / or dextran). In some embodiments, the injector 300 delivers fluids during a flushing procedure, as described below. In some embodiments, the injector 300 delivers contrast agents and / or other fluids through a delivery catheter 50 with an ID of 5 French to 9 French, an ID of 0.53 inches to 0.70 inches, or an ID of 0.0165 inches to 0.027 inches. In some embodiments, the contrast agents and / or other fluids are delivered through a 4 French (e.g., for distal injection) delivery catheter. In some embodiments, the injector 300 delivers contrast and / or other fluids through the lumen of one or more delivery catheters 50, while one or more smaller delivery catheters 50 are also present within the lumen 52. In some embodiments, the injector 300 is configured to simultaneously and / or sequentially deliver two dissimilar fluids, e.g., a first fluid delivered from a first container and containing a first concentration of contrast and a second fluid delivered from a second container and containing less or no contrast. The injector 300 may include one or more functional elements (e.g., functional element 303 shown in FIG. 1 ). The functional element 303 may include one or more functional elements (e.g., one or more sensors, transducers, and / or other functional elements, as described in more detail below).

[0179] The graft 85 may include a graft (e.g., a temporary or long-term graft) for treating one or more of a vascular occlusion or an aneurysm. In some embodiments, the graft 85 includes one or more grafts selected from the group consisting of a flow diverter, a Pipeline™ flow diverter, a Surpass™ flow diverter, an embolic coil, a stent, a Wingspan™ stent, a covered stent, an aneurysm treatment graft, and combinations of one or more of these. The delivery device 80 may include a catheter or other tool used to deliver the graft 85, for example, when the graft 85 has a self-expanding or balloon-expandable portion. The graft delivery device 80 may include a functional element (e.g., functional element 83 shown in FIG. 1 ). The functional element 83 may include one or more functional elements (e.g., one or more sensors, transducers, and / or other functional elements, as described in more detail below). In some embodiments, the system 10 includes a probe 100, one or more implants 85, and / or one or more implant delivery devices 80, as described in applicant's co-pending U.S. Provisional Patent Application No. 62 / 212,173, filed August 31, 2015, entitled "Imaging System Includes Imaging Probe and Delivery Devices," the contents of which are incorporated herein in their entirety for all purposes. In some embodiments, the probe 100 is configured to collect data regarding the implant 85 and / or implant delivery device 80 (e.g., anatomical location, orientation, and / or other placement data of the implant 85 and / or implant delivery device 80) after the implant 85 and / or implant delivery device 80 is inserted into a patient's body.

[0180] The treatment device 91 may include a device for treating an occlusion or other treatment selected from the group consisting of a balloon catheter, a drug-eluting balloon, an aspiration catheter, a sonolysis device, an atherectomy device, a thrombus removal device such as a stent retriever device configured and designed to dilate a stenosis or other vascular narrowing, a Trevo™ stentriever, a Solitaire™ stentriever, a Revive™ stentriever, an Eric™ stentriever, a Lazarus™ stentriever, a stent delivery catheter, a micro-braided graft, an embolization system, a WEB™ Embolization System, a Luna™ Embolization System, a Medina™ Embolization System, and combinations of one or more of these. In some embodiments, the treatment device 91 includes a treatment device selected from the group consisting of a stent retriever, an embolic coil, an embolic coil delivery catheter, a stent, a covered stent, a stent delivery device, an aneurysm treatment graft, an aneurysm treatment graft delivery device, a flow diverter, a balloon catheter, and combinations thereof. In some embodiments, the probe 100 is configured to collect data about the treatment device 91 (e.g., location, orientation, and / or other positioning data of the treatment device 91) after the treatment device 91 is inserted into the patient's body. The treatment device 91 may include functional elements, such as the functional element 93 shown in FIG. 1 .

[0181] The second imaging device 92 may include an imaging device (e.g., one or more imaging devices selected from the group consisting of an X-ray, an X-ray fluoroscopy device, such as a one-way or two-way X-ray fluoroscopy device, a CT scanner, an MRI, a PET scanner, an ultrasound imaging device, and combinations of one or more of these).

[0182] Each of functional elements 53, 83, 93, 113, 123, 133, 203 and / or 303 may include one or more sensors, transducers and / or other functional elements, as described in more detail below.

[0183] In some embodiments, functional element 113 is located proximate to optical assembly 130 (e.g., functional element 113b shown in FIG. 1A located on the same axis as optical assembly 130 and / or proximal to but distal to optical assembly 130). In some embodiments, imaging probe 100 includes functional element 113a shown in FIG. 1. Functional element 113a is shown located at a proximal portion of shaft 110, but may be located elsewhere in probe 100, such as on, in, and / or within connector 102. Functional elements 113a and / or 113b (singly or collectively, functional elements 113) may each include one or more functional elements, for example (one or more sensors, transducers, and / or other functional elements, as described in more detail below).

[0184] In some embodiments, functional element 53, 83, 93, 113, 123, 133, 203, and / or 303 includes a sensor (e.g., a sensor configured to provide a signal related to a parameter of a component of system 10 and / or a sensor configured to provide a signal related to a patient parameter). Functional element 53, 83, 93, 113, 123, 133, 203, and / or 303 may include one or more sensors selected from the group consisting of a physiological sensor, a pressure sensor, a strain gauge, a position sensor, a GPS sensor, an accelerometer, a temperature sensor, a magnetic sensor, a chemical sensor, a biochemical sensor, a protein sensor, a flow sensor such as an ultrasonic flow sensor, a gas detection sensor such as an ultrasonic bubble detector, an acoustic sensor such as an ultrasonic sensor, and a combination of one or more of the foregoing. In some embodiments, functional elements 53, 83, 93, 113, 123, 133, 203, and / or 303 may include one or more physiological sensors selected from the group consisting of a pressure sensor such as a blood pressure sensor, a blood gas sensor, a flow sensor such as a blood flow sensor, a temperature sensor (e.g., a temperature sensor for blood or other tissue), and a combination of one or more of these. In some embodiments, algorithm 240 is configured to process signals received by a sensor, such as signals provided by a sensor described herein. In some embodiments, functional elements 53, 83, 93, 113, 123, and / or 133 include a position sensor configured to provide a signal related to a three-dimensional vascular path (e.g., a vascular lumen path). In some embodiments, functional elements 53, 83, 93, 113, 123, and / or 133 include a magnetic sensor configured to provide a signal for positioning optical assembly 130 relative to one or more implanted devices (e.g., one or more implants 85 including ferrous or other magnetic portions). In some embodiments, functional elements 53, 83, 93, 113, 123 and / or 133 include a flow sensor, e.g., a flow sensor configured to provide a signal related to blood flow through a blood vessel at patient site PS (e.g., blood flow through a stenosis or other partially occluded portion of a blood vessel).In these embodiments, algorithm 240 may be configured to assess blood flow (e.g., assess the severity of the blockage) (e.g., provide information to a clinician regarding potential treatment of the blockage). In some embodiments, optical assembly 130 includes functional element 113, e.g., when optical assembly 130 is configured and designed as a sensor to provide a signal related to blood flow. In some embodiments, functional elements 53, 83, 93, 113, 123, and / or 133 include a flow sensor configured to provide a signal used to indicate vascular anatomical data along with the flow data. The flow sensor may be used to model pre- and post-intervention flow (e.g., aneurysm flow), assess risk of rupture, and / or assess the appropriateness of the intervention. In some embodiments, functional elements 53, 83, 93, 113, 123, and / or 133 include an ultrasound sensor configured to provide a signal (e.g., image or frequency data) that is indicated along with information derived from the near-field light provided by optical assembly 130. In some embodiments, functional elements 53, 83, 93, and / or 113 are configured to be deployed by their associated devices (e.g., such that the functional elements are implanted within a patient's body). Implantable functional elements 53, 83, 93, and / or 113 may include microchips and / or MEMS components. Implantable functional elements 53, 83, 93, and / or 113 may include at least a portion that is visualized (e.g., by image data collected by probe 100 and / or a separate imaging device, such as second imaging device 92).

[0185] In some embodiments, functional elements 53, 83, 93, 113, 123, 133, 203 and / or 303 include one or more transducers selected from the group consisting of a heating element (e.g., a heating element configured to transfer heat sufficient to ablate tissue), a cooling element (e.g., a cooling element configured to transfer cryogenic energy sufficient to ablate tissue), an acoustic transducer such as an ultrasound transducer, a vibration transducer, and a combination of one or more of the foregoing.

[0186] In some embodiments, functional elements 53, 83, 93 and / or 113 include pressure relief valves configured to prevent excessive pressure buildup in the associated device. In some embodiments, functional elements 53, 83, 93 and / or 113 have one or more side holes (e.g., one or more side holes used to deliver fluids in the cleaning procedures described herein).

[0187] In some embodiments, functional elements 53, 83, 93, 113, 123, 133, 203, and / or 303 include a visualization indicia. For example, functional elements 53, 83, 93, and / or 113 include an indicia selected from the group consisting of a radiopaque indicia, an ultrasound reflective indicia, a magnetic indicia, a ferrous material, and combinations of one or more of the foregoing.

[0188] The probe 100 is configured to collect image data (e.g., image data collected during rotation and / or retraction of the optical assembly 130). The optical assembly 130 is rotated by rotating the core 120. The optical assembly 130 is retracted by retracting the shaft 110. The optical assembly 130 collects image data while surrounded by a portion of the shaft of a delivery catheter 50 (e.g., when within the transparent portion 57 of the delivery catheter) and / or when there is no catheter 50 surrounding the optical assembly 130 (e.g., when the optical assembly 130 is advanced beyond the distal end 59 of all delivery catheters 50 into which the probe 100 is inserted).

[0189] During collection of image data, a flushing procedure may be performed, such as by delivering one or more fluid injectants 305 (e.g., propelled by an injector 300 or other fluid delivery device) to remove blood or other somewhat opaque material (hereinafter, non-transparent material) adjacent to the optical assembly 130 (e.g., to remove non-transparent material between the optical assembly 130 and the delivery catheter and / or between the optical assembly 130 and the blood vessel wall) to ensure that the light distributed by the optical assembly 130 reaches and reflects back from all tissues (and other objects being imaged). In these flushing embodiments, the injectants 305 may include an optically transparent material, such as saline. The injectants 305 may include one or more visualization materials, as described below. The injectants 305 may be delivered by an injector 300 as described above.

[0190] The flushing rate required to clear the area around the optical assembly 130 may be inversely proportional to the viscosity of the flushing medium. This mathematical relationship may be caused by the downstream drainage of the flushing medium in the capillary bed. If the capillary bed drains slowly, it is easier to maintain upstream flushing at the original blood pressure or slightly higher to prevent fresh blood from entering the vessel being imaged (e.g., in proximity to the optical assembly 130). Conversely, if the capillary bed drains rapidly, a corresponding increase in flushing rate may be necessary. Because saline (a standard flushing medium) has a viscosity approximately one-third that of blood (e.g., 1 Cp vs. 3.3 Cp), approximately three times the normal flow rate would be required to clear the vessel (in the area adjacent to the optical assembly 130), which may pose a risk to the integrity of the vessel. Alternatively, a contrast agent (e.g., a radiopaque contrast agent) may be used for flushing. The contrast material has a high viscosity (due to its high iodine concentration, typically about 300 mg / ml). System 10 may include a flushing fluid containing a contrast agent, for example, a contrast agent having an iodine concentration of between 50 mg / ml and 500 mg / ml (e.g., which correlates with a viscosity between about two and five times that of blood). System 10 may include a flushing fluid (e.g., a radiopaque or other visualization flushing fluid) having a viscosity between 1.0 Cp and 20 Cp (e.g., at a temperature of about 37°C).

[0191] Alternatively or in addition to its use in the cleaning procedure, the injectate 305 may include a material configured to be viewed by the second imaging device 92, for example, the injectate 305 may include a contrast agent configured to be viewed by the second imaging device 92 including an X-ray fluoroscope or other X-ray device, an ultrasound reflective material configured to be viewed by the second imaging device 92 including an ultrasound imaging device, and / or a magnetic material configured to be viewed by the second imaging device 92 including an MRI.

[0192] The injectate 305 may be delivered by one or more delivery catheters 50 (e.g., to the space between a first delivery catheter 50 and an inserted delivery catheter 50, or to the space between a delivery catheter 50 and an inserted probe 100). The injectate 305 delivered during a flushing procedure (or other procedure for delivering injectate 305) may be delivered out the distal end 59 of a delivery catheter 50 (e.g., a distal end 59 disposed proximal to the optical assembly 130), as described in applicant's co-pending U.S. Provisional Patent Application No. 62 / 212,173, filed August 31, 2015, entitled "Imaging System Includes Imaging Probe and Delivery Devices," the contents of which are incorporated herein in their entirety for all purposes. Alternatively, or in addition, any delivery catheter 50 may have one or more side holes (e.g., the illustrated side hole 58 disposed on the distal portion of delivery catheter 50c) extending through a portion of the associated shaft 51. In some embodiments, the delivery catheter 50 comprises a microcatheter having a side hole 58 located on its distal portion, e.g., a microcatheter having an ID of less than 0.027 inches (e.g., a microcatheter having an ID of 0.016 inches to 0.027 inches or 0.021 inches to 0.027 inches). In some embodiments, irrigation fluid is delivered from both the side hole 58 and the distal end 59 of the delivery catheter 50 toward the optical assembly 130. The side hole 58 may be configured and designed to allow irrigation fluid to pass through the shaft 51 and through the side hole 58, for example, when a separate shaft (e.g., the shaft 51 of an additional delivery catheter 50 or the shaft 110 of the probe 100) is inserted into the delivery catheter 50. Delivery of irrigation fluid through the side hole 58 and / or the distal end of the delivery catheter 50 may be performed, for example, during collection of image data, to remove blood from the area from the lumen portion surrounding the optical assembly 130.

[0193] In some embodiments, delivery of injectate 305 during the flushing procedure is based on parameters selected from the group consisting of a predetermined volume of injectate to be delivered, a predetermined time for delivering the injectate, an amount of delivery time including a time from before retraction of shaft 110 to the completion of image data collection (e.g., completion of retraction of shaft 110), and a combination of one or more of the foregoing. In some embodiments, during the flushing procedure, injector 300 delivers fluid at an approximate flow profile selected from the group consisting of 5 ml / sec for 6 seconds of contrast (e.g., 20% to 100% saline miscible contrast) (e.g., for imaging of the carotid artery with 4 seconds of image data collection), 4 ml / sec for 6 seconds of contrast (e.g., 20% to 100% saline miscible contrast) (e.g., for imaging of the vertebral artery with 4 seconds of image data collection), and a combination of one or more of the foregoing. In some embodiments, the flushing procedure involves delivery (e.g., by one or more delivery catheters 50) of infusate 305 for 2-8 seconds (e.g., about 4 seconds of infusate delivery) (e.g., to purge blood or other non-transparent fluids from the luminal portion of a blood vessel or other area surrounding the optical assembly 130 during image data acquisition from the patient site PS). In a similar flushing procedure, infusate 305 may be delivered at a rate of between 3 ml / sec and 9 ml / sec (e.g., about 6 ml / sec through one or more delivery catheters 50) to purge non-transparent materials.

[0194] In these flushing procedures, the infusate 305 may comprise a transparent fluid selected from the group consisting of saline, contrast, dextran, and combinations of one or more of these. In some embodiments, the volume of infusate 305 delivered during the flushing procedure and / or the delivery time of the infusate 305 is determined by parameters selected from the group consisting of the type of procedure being performed, the diameter of the vessel in which the optical assembly 130 is placed, the length of retraction, the duration of the retraction, and combinations of one or more of these. In some embodiments, the infusate 305 is delivered during the flushing procedure by a delivery catheter having an ID greater than 0.027 inches (e.g., a first delivery catheter 50 having a distal end 59 more proximal than a second delivery catheter 50 inserted therein). In some embodiments, the infusate 305 is delivered into associated multiple delivery catheters 50 through multiple lumens 52 (e.g., into the space between two or more pairs of delivery catheters 50 designed to slidingly receive each other in a sequential pattern).

[0195] In some embodiments, the injectate includes a first fluid (e.g., a fluid including saline and / or a fluid containing no or minimal contrast) and a second fluid (e.g., a second fluid including saline and contrast) delivered during a first portion of the flushing procedure, e.g., to limit the amount of contrast delivered to the patient during the flushing procedure. In these embodiments, the injector 300 may include two containers (e.g., a first container for delivering the first fluid and a second container for delivering the second fluid) (as described above). When including two containers, the injector 300 may be configured to deliver the fluids in each container at different rates, e.g., to achieve different pressures and / or to perform flushing through catheters with different IDs.

[0196] As described herein, the optical assembly 130 may be rotated (e.g., by rotating the core 120) and retracted (e.g., by retracting the shaft 110 with the retraction assembly 220) during image data collection, such as combining rotation and retraction to generate a 3D image of the patient portion PS. In some embodiments, the optical assembly 130 rotates at a speed of 40 rps to 1000 rps (e.g., about 250 rps). In some embodiments, the optical assembly 130 rotates at a first speed during imaging mode and a second speed during preview mode (the imaging and preview modes described above). In some embodiments, the retraction of the optical assembly 130 extends over a distance of 1 cm to 15 cm, e.g., about 4 cm. In some embodiments, the optical assembly 130 retracts at a speed of 1 mm / sec to 60 mm / sec. In some embodiments, the optical assembly 130 retracts approximately 7.5 cm over 4 seconds and / or has a retraction speed of approximately 20 mm / s. In some embodiments, the optical assembly 130 retracts with an axial resolution of 5 μm to 20 μm and / or a longitudinal resolution of 20 μm to 100 μm. The longitudinal resolution is dependent on two factors: the spot size (light beam cross-section) at the tissue surface being imaged and the spacing between successive rotations of the optical assembly 130 during retraction. A rotation speed of 100 rps and a retraction speed of 22 mm / s results in a 200 μm pitch between rotations. In these configurations, a spot size of 20 μm to 40 μm will result in the collection of image data that insufficiently samples the object being imaged. The system 10 may be configured to closely match the spot size to the pitch, for example, by correlating the spot size with the rotation speed and / or the retraction speed.

[0197] In some embodiments, the imaging system 10 is constructed, designed, and used to generate images as described in applicant's co-pending U.S. Provisional Patent Application No. 62 / 212,173, filed August 31, 2015, entitled "Imaging System Includes Imaging Probe and Delivery Devices," the contents of which are incorporated herein in their entirety for all purposes.

[0198] In some embodiments, system 10 is configured to assist in the selection, placement, and / or use of a treatment device 91. The treatment device 91 may include a stentrier configured to remove thrombus or other occlusive material from a patient, such as when imaging probe 100 images the anatomy and / or treatment device 91 to generate anatomical information (e.g., for use in selecting a size or other shape of the stentrier), visualize the stent retriever at the site of an occlusion (e.g., for positioning the treatment device 91), and / or visualize occlusive material (e.g., thrombus) engaged with and / or not removed by the treatment device 91. In some embodiments, system 10 is configured to quantify the volume of thrombus, such as thrombus removed by treatment device 91. The thrombus visualized by system 10 may include thrombus selected from the group consisting of residual thrombus from an acute stroke, thrombus remaining after a thrombectomy procedure, thrombus present after flow diverter implantation, and combinations thereof.

[0199] In some embodiments, system 10 is configured to provide anatomical information used to select an implantation site and / or select a particular implantable device, such as graft 85 of system 10 described above, to be implanted within the patient. System 10 may be configured to image at least one perforator artery of the patient (e.g., to image one, two, or more perforator arteries having a diameter of 50 μm or greater). Graft 85 may be implanted within the patient via graft delivery device 80, for example, if graft 85 includes a stent and / or flow diverter. System 10 may be configured to perform a function selected from the group consisting of detecting and / or quantifying apposition of graft 85 (e.g., stent or flow diverter malapposition), providing quantitative and / or qualitative information regarding the size and / or placement of graft 85 implanted within the patient (e.g., information regarding perforator location, perforator shape, neck size, and / or flow diverter mesh density), and combinations of one or more of the foregoing. The system 10 may be configured to provide information regarding a parameter of the graft 85 selected from the group consisting of porosity, length, diameter, and combinations thereof. The system 10 may be configured to provide information regarding the porosity of the graft 85, including the porosity of one or more portions of the graft 85 (e.g., a portion positioned adjacent to a side branch of a blood vessel into which the graft 85 is implanted). The system 10 may be configured to provide porosity information based on the wire diameter of the graft 85. The system 10 may be configured to provide information regarding the implantation of a second graft 85 (e.g., implantation site or device information) within the patient's body. In those embodiments using two implantable devices 85, the first and second implantable devices may include similar or different devices (e.g., a stent and a flow diverter, two stents, or two flow diverters). The system 10 may be configured to collect image data during deployment of one or more grafts 85.The system 10 may be configured to collect image data for use in modifying the implanted device (e.g., during and / or after implantation), such as modifying the porosity of the implant 85 (e.g., by a treatment device 91 including a balloon used to adjust the porosity of a partially or fully implanted implant 85).

[0200] Specialized catheters have been used for decades to image previously inaccessible body regions (e.g., coronary arteries, neurovascular arteries, the endocrine system, pulmonary airways, etc.). Technological advances enable higher resolution, new modalities (e.g., spatially resolved spectroscopy), and lower-cost probes, resulting in widespread product development for these applications. Limitations and other issues with current catheters are discussed below. As imaging catheters become smaller, traditional optics or so-called coherent fiber bundles often become unusable. Therefore, distal optics are typically rotated at high speeds to generate cross-sectional views of body cavities. Rather than generating traditional multi-pixel "snapshots," the rotating optics build up images one or two pixels at a time by scanning a single imaging point, similar to the raster scan employed by older CRTs. This rotation, combined with longitudinal motion ("retreat"), can generate a spiral-scanned image of the artery or lumen, which can be visualized as a 3D image. Most currently available imaging catheters have a distally located imaging element optically or electrically connected to the proximal end. The imaging element is attached to a mechanical transmission that produces rotation and retraction. Recent advances in micromotor technology have enabled the use of a distally located drive for mechanical transmission, although retraction is still required. However, these motors are expensive and relatively large (available designs do not allow for probes with an OD of less than 1 mm).

[0201] Numerous commercially available "torque shafts" exist, which are small wire-wrapped tubes used to transmit torque along long, flexible shafts. Such devices are currently commonly used in intravascular ultrasound (IVUS) and optical coherence tomography (OCT) procedures. Imaging probes combined with torque shafts perform rotational scanning, for example, within coronary arteries. However, these devices typically have an OD of approximately 0.8 mm to 1.3 mm (2.4 Fr to 4 Fr), and are therefore two to four times larger than devices needed for neurological applications. Currently, such torque shafts cannot be scaled to the size required to realize scanning imaging catheters with ODs less than 0.7 mm.

[0202] Because optical imaging in arteries requires clearing of blood, which obscures the view, usually with a flushing solution, the diameter of the imaging catheter becomes very important in smaller or occluded vessels (e.g., due to the use of smaller guides). Because it is the diseased or occluded vessels that need to be imaged for diagnosis and treatment, the imaging probe 100 may be designed with a small diameter (e.g., 0.025 inch or less, 0.016 inch or less, or 0.014 inch or less OD).

[0203] The literature (Petersen et al., U.S. Patent No. 6,891,984 [the '984 patent]; Crowley, U.S. Patent No. 6,165,127 [the '127 patent], the contents of each of which are incorporated herein by reference in their entirety and for all purposes) discloses the use of a viscous fluid located in the distal region of the imaging catheter to prevent kinking.

[0204] Achieving uniform rotational scanning at the distal tip of a single fiber imaging catheter while keeping the overall device size below 500 μm OD is quite challenging. Because adding a motor to a distal tip with an OD of less than 1 mm is currently impractical due to the associated wires and size issues, a method must be found to apply torque to the proximal end and transmit it to the distal tip (which may be located 3 meters away in some clinical applications) while maintaining a uniform rotational speed. (See Tsung-Han Tsai, Benjamin Potsaid, Yuankai K. Tao, Vijaysekhar Jayaraman, James Jiang, Peter J.S. Heim, Martin F. Kraus, Chao Zhou, Joachim Hornegger, Hiroshi Mashimo, Alex E. Cable, James G. Fujimoto, "Ultrahigh speed endoscopic optical coherence tomography using micro-motor imaging catheter and VCSEL technology," Biomed Opt Express. July 1, 2013; 4(7):1119-1132.) Uniform speed is paramount to image fidelity, as non-uniform rotation can lead to smeared and significantly distorted images (see Figure 3). Considering the extremely low rotational stiffness inherent in glass fibers, the challenges of uniformly rotating the distal tip by driving the proximal end can be understood. Uniform rotation is critical in endoscopic techniques to obtain accurate peripheral images. The industry has coined the term "NURD" (non-uniform rotational distortion) to describe these deleterious effects.

[0205] An example of distortion due to NURD is shown in Figure 3. The solid curve simulates a perfectly circular artery with a diameter of 4 mm. The curve with square data points is an image of the same artery wall with NURD. In this case, the catheter rotation is slowed by 50% for a small portion of the cycle and accelerated by 50% for another portion so that the average distal rotational speed matches the proximal rotational speed (otherwise twisting would rapidly accumulate and damage the core 120). It can be seen that this NURD can lead to significant measurement errors. The imaging probe 100, and other components of the system 10, are configured to mitigate these types of distortions.

[0206] The '127 patent discloses the use of a viscous fluid located within a lumen of the ultrasound catheter. The purpose of using the viscous fluid is to provide a load on the torque wire so that the wire transitions to a torsionally stiff state at a moderate rotational speed. As described in the '127 patent, the fluid is contained within a separate lumen formed within the main catheter, increasing the overall size of the device. The fluid does not contact the imaging tip, and ultrasonic energy does not propagate through the fluid. This approach also requires the use of a torque wire, reducing the degree to which the required size reduction can be achieved. In an imaging probe of the present concept, one or more viscous fluids (e.g., one or more fluids 190) can be provided to intentionally twist (i.e., wind) the core 120. The twisting may include a dynamic twist that varies with the overall (i.e., end-to-end) frictional load (torque) of the probe 100, resulting in a relatively steady rotational speed. The probe 100 may be configured to vary the amount of twist during retraction of one or more portions of the probe 100 (eg, retraction of the core 120 and / or retraction of the core 120 and shaft 110).

[0207] The '984 patent utilizes a viscous fluid with a high refractive index to provide a viscous load so that the optical fiber acts as a torque transmitter and to reduce the refractive effects at the curved sheath boundary. This configuration allows for some size reduction. However, the '984 patent does not describe or disclose a mechanism for limiting the geometric extent of the fluid at the distal tip. Fluid migration is unavoidable during shipping and storage, inevitably resulting in performance degradation. Similarly, the '984 patent fails to address a potential problem that can arise during retraction of the inner fiber: the formation of voids in the viscous fluid, which can have a relatively large optical effect (so-called "bubble artifacts"; see, e.g., "Expert review document on methodology, terminology, and clinical applications of optical coherence tomography: physical principles, methodology of image acquisition, and clinical application for assessment of coronary arteries and atherosclerosis," Francisco Prati et al., European Heart Journal, November 4, 2009). In some embodiments, probe 100 is configured to rotate core 120 unidirectionally (i.e., in one direction) during use. In some embodiments, probe 100 includes a torque shaft (e.g., torque shaft 110b described below) within shaft 110 that is frictionally engaged with core 120. Torque shaft 110b may extend from the proximal end of probe 100 to a location proximal to optical assembly 130. For example, a torque shaft may have a distal end that is 5 cm or more away from optical assembly 130 or that is proximal to the proximal-most location of shaft 110 placed within the patient.

[0208] An imaging probe 100 filled with (e.g., sealed) a liquid, gel, or other fluid has the advantage that it does not require purging (e.g., to remove air bubbles). Fluid 190a or 190b may be configured as a lubricant to reduce friction between core 120 and shaft 110. In embodiments in which core 120 is retracted relative to shaft 110 to acquire images, a cavity is formed at the end of core 120 that can be filled with a liquid, gel, or other fluid (e.g., fluid 190).

[0209] This region is difficult for fluid to "fill" because it must be supplied from the proximal end of the shaft 110 and travel the length of the core 120. Low pressure can develop, which can lead to bubble formation. In embodiments of the inventive concept, rather than retracting the core 120 into the shaft 110, the entire imaging probe 100 is retracted during image data collection (i.e., the core 120 and shaft 110 are retracted together with no relative axial motion between the two). Because the shaft 110 moves with the core 120, the presence of a low-pressure region at the end of the imaging core is eliminated, or at least mitigated.

[0210] As shown in FIG. 4 , such “reciprocal” motion between the shaft 110 and core 120 avoids relative motion between the optical assembly 130 and the shaft 110, allowing the shaft 110 to have a larger diameter around the optical assembly 130. A larger diameter optical assembly 130 (e.g., larger diameter lenses of the optical assembly 130) provides more light collection, which is associated with a brighter image. This configuration can also provide lenses of the optical assembly 130 with focal lengths located farther from the OD (i.e., outer surface) of the shaft 110 surrounding the optical assembly 130, improving distal image quality. Alternatively, or in addition, and as shown in FIG. 4 , the OD of the optical assembly 130 can be larger than the ID of at least a portion of the shaft 110 proximal to the optical assembly 130. In these embodiments, the optical assembly 130 and the shaft 110 can be simultaneously retracted during collection of image data from the region of interest.

[0211] In some embodiments, the wall of the shaft 110 is relatively thick along most of its length compared to a thinner wall of the shaft 110 at the distal portion of the shaft 110 (e.g., thinner than a portion of the shaft 110 proximal to the optical assembly 130). Such a configuration can improve longitudinal and torsional control for positioning the imaging probe 100. In some embodiments, the shaft 110 may have a stiffened portion disposed around the optical assembly 130, e.g., a stiffened portion of the shaft 110 including a different (stiffer) wall material, a braided shaft portion, and / or a stiffening element (e.g., wire embedded within the wall of the shaft 110). The stiffened distal portion of the shaft 110 may be associated with a thinner wall, which in turn may be associated with an optical assembly 130 including larger optical components (e.g., one or more lenses with a larger diameter) without, for example, needing to increase the OD of the shaft 110 surrounding the optical assembly 130. In some embodiments, the shaft 110 has varying mechanical properties along its length (e.g., a stiffened proximal portion for "pushability") and gradually decreasing stiffness distally (e.g., to improve maneuverability and safety when advancing through tortuous anatomy).

[0212] Also, as shown in FIG. 4 , optical assembly 130 may include lens 131 and reflective element 132 (e.g., to “redirect” light). Reflective element 132 is configured such that optical assembly 130 is asymmetric. When optical assembly 130 is rotated at high speeds, the presence of a viscous liquid or other viscous fluid in the optical path surrounding optical assembly 130 can potentially cause voids in the area behind reflector 132. As shown in FIG. 5 , in some embodiments, probe 100 includes a first fluid, fluid 190a, surrounding core 120 and a second, different fluid, fluid 190b, surrounding optical assembly 130, such that fluid 190a may be configured to provide a first function (e.g., prevent or at least reduce undesired rotational fluctuations of core 120) while fluid 190b provides a second function (e.g., prevent or at least reduce voids around optical assembly 130). In some embodiments, to optimize rotational speed uniformity, the viscosity of fluid 190b may be selected to be relatively low, e.g., to minimize cavitation, while the viscosity of fluid 190a may be selected to be relatively high (e.g., at least more viscous than fluid 190b).

[0213] In neurological placements, the imaging probe 100 is typically placed within the patient's femoral vasculature. The vasculature proximal to the neuroimaging region is highly tortuous, beginning at the carotid bifurcation from the aorta. In some embodiments, by using a high-viscosity fluid 190a in the central and / or proximal portions of the imaging probe 100, the fluid 190a can provide the additional function of lubricating the core 120 as it rotates within the shaft 110 (e.g., useful lubrication due to the highly tortuous portion in which the imaging probe 100 is placed). The resulting reduced friction reduces stress on the core 120, allowing for smoother movement at any discontinuities in the shaft 110 or core 120. The fluid 190 may be configured to provide sufficient lubricity or other beneficial parameters to eliminate or at least reduce (herein "reduce") adverse effects that would otherwise occur when the probe 100 is placed within tortuous anatomy (e.g., when the distal portion 119a is placed distally adjacent to the carotid artery). In these embodiments, the fluid 190 may include a high viscosity fluid.

[0214] Additionally, the presence of the high-viscosity fluid 190a helps maintain the low-viscosity fluid 190b at the distal end of the shaft 110 prior to use, as the high-viscosity fluid 190a in the shaft 110 acts as a barrier, reducing the likelihood of the fluid 190b migrating from the imaging region around the optical assembly 130 prior to use (e.g., during sterilization and shipping of the imaging probe 100). In some embodiments, a sealing element (e.g., sealing element 116) is disposed between two or more different fluids 190. Alternatively, a separation element may not be present if one or more fluids 190 comprises, for example, a gel configured to prevent mixing with adjacent fluids 190.

[0215] In some embodiments, the imaging probe 100 includes an inertial assembly including an impeller, propeller, or other inertial-based element configured to reduce undesired fluctuations in the rotational speed of the optical assembly 130, as shown, for example, in FIG. 6 . The imaging probe 100 includes an impeller 182 attached to the core 120. Drag on the impeller 182 “winds” the core 120, reducing unintended or undesired fluctuations in the rotational speed of the fiber. The impeller 182 operates to rotate the fluid 190 between the shaft 110 and the optical assembly 130. The blades of the impeller 182 create a drag force that remains uniform throughout rotation due to its symmetry about its axis of rotation. In some embodiments, the radially extending end of the impeller 182 intentionally contacts the inner wall of the shaft 110 to provide an alternative or incremental drag force. Impeller 182 may include one or more protrusions from core 120 (e.g., protrusions that frictionally engage shaft 110 and / or create shear forces that apply loads to core 120 during rotation). Impeller 182 may include one or more protrusions from shaft 110 (e.g., protrusions that frictionally engage core 120 and / or create shear forces that apply loads to core 120 during rotation).

[0216] The impeller 182 may be configured to wind up the core 120. The impeller 182 may be configured to frictionally engage the fluid 190 and / or the shaft 110 during rotation of the core 120. The impeller 182 may include a component selected from the group consisting of a turbine, a vaned microstructure, a flywheel, and combinations of one or more of these.

[0217] Liquids, gels, or other fluids disposed within shaft 110 may be prone to the formation of bubbles. These bubbles, if present in the optical path, reduce light transmission. In some embodiments, fluid 190a and / or fluid 190b (singly or collectively, fluids 190) may be pressurized (e.g., to a pressure of 100 psi or greater) to prevent or reduce the size of any bubbles within shaft 110, as described herein with reference to FIG. 7 .

[0218] Small tire inflators are commonly used to fill bicycle tires. They are available in sizes smaller than 1 inch, which makes them suitable for this application. These and similar inflators can provide pressures up to and exceeding 100 psi, which can significantly reduce bubble size when applied to a fluid 190. Assuming a bubble size of 0.1 microliters at atmospheric pressure, the bubble size at 100 psi is: V p =V a P a / P p It can be calculated using: V p = foam volume under pressure V a = bubble volume at atmospheric pressure (e.g., 0.1 μL) P a = atmospheric pressure (14.7 PSI) P p = Pressure device pressure (e.g. 100 psi) is.

[0219] Under pressure, the bubble volume decreases from 0.1 μL to 0.0147 μL. The corresponding bubble diameter decreases from 0.022 inches to 0.011 inches, which mitigates or eliminates the detrimental effect on the optical beam.

[0220] FIG. 7 is a cross-sectional view of an imaging probe including a pressurization system consistent with the concepts of the present invention. The imaging probe 100 includes a shaft 110 having a proximal end 111, a lumen 112, a core 120, and an optical connector 102, each of which may have a configuration and design similar to that described with reference to FIG. 1. The imaging probe 100 may include a pressurization assembly 183 (e.g., a pressurized gas canister) fluidly connectable to the lumen 112 via a valve 184 (e.g., a one-way check valve). In some embodiments, each imaging probe 100 is provided with a pressurization assembly 183. Alternatively, a single pressurization assembly 183 may be reused (e.g., for use with multiple imaging probes 100 in multiple clinical procedures). In some embodiments, the pressurization assembly 183 may be pre-attached to the shaft 110 or may be detachable. In some embodiments, the pressurization assembly 183 may be operably attached and / or activated shortly prior to clinical use of the imaging probe 100 to pressurize fluid, for example, within the lumen 112 or other location within the imaging probe 100, to reduce the size of one or more air bubbles in the fluid, such as the fluid 190 described herein.

[0221] In some embodiments, a sealing element 151 (e.g., a compressible O-ring) is disposed between the core 120 and the shaft 110 near the proximal end 111 of the shaft 110. The shaft 110 and the sealing element 151 may be configured and designed to maintain a relative seal when the lumen 112 is pressurized (e.g., as described above), while allowing the core 120 to rotate within the shaft 110 and the sealing element 151. The sealing element 151 may seal during rotation of the core 120 within the shaft 110. Simultaneous retraction of the shaft 110 and the core 120 during imaging, as described herein, simplifies the construction of the sealing element 151. In some alternative embodiments, the core 120 is retracted into the shaft 110, and the sealing element 151 is configured to maintain a seal during retraction.

[0222] In some embodiments, at least a portion of the shaft 110 is configured to radially expand as fluid 190 is pressurized, as shown in, for example, FIGS. 15A-15C. A pressurization assembly 183 is attached to the connector 102 such that fluid 190 can be introduced and / or forced into and / or within the shaft 110. In FIG. 15A, the proximal portion 111a of the shaft 110 is expanded (e.g., the lumen 112 is expanded in the region of the proximal portion 111a). In FIG. 15B, the proximal portion 111a and the central portion 115 of the shaft 110 are expanded. In FIG. 15C, the proximal portion 111a, the central portion 115, and the distal portion 119a are expanded. In these embodiments, the system 10 may be configured to rotate the core 120 after the shaft 110 is fully expanded, as shown in FIG. 15C. The expansion of shaft 110 can create and / or increase a space between core 120 and the inner wall of shaft 110. In some embodiments, shaft 110 remains at least partially expanded (e.g., shaft 110 is plastically deformed) when the pressure of fluid 190 is reduced (e.g., to atmospheric pressure). Shaft 110 may be configured to expand to a first diameter (ID and / or OD) when fluid 190 is pressurized to a first pressure and to expand to a second, larger diameter when fluid 190 is pressurized to a second, higher pressure. In some embodiments, shaft 110 is configured to become more rigid as the pressure of fluid 190 increases.

[0223] There may be two attachments from the probe 100 (e.g., a disposable catheter) to the non-disposable components of the system 10. One attachment is to the shaft 110 (a non-rotating shaft), and the other is to the core 120. The attachment of the imaging probe 100 to the console 200 may include two functional attachments. One attachment includes attachment of the shaft 110 to a retraction assembly (e.g., retraction assembly 220 described herein) so that the shaft 110 (and optical assembly 130) can be retracted during image data collection. The other attachment includes attachment of the core 120 to a rotation assembly (e.g., rotation assembly 210) so that the core 120 can be rotated during image data collection. Both attachments may be retracted together during image data collection. The attachment of the core 120 forms an optical connection between the core 120 and an imaging assembly (e.g., imaging assembly 230 described herein) and can provide motive force to rotate the core 120 (e.g., attachment to rotation assembly 210).

[0224] The imaging system and associated imaging probes of the present concept offer enhanced compatibility with conventional therapeutic catheters, such as those used in the neurological procedures described herein.

[0225] Stent retrieval devices (also referred to as "stent retrievers") are used for endovascular recanalization. While the success rate of revascularization is high, multiple passes of the stent retriever are required to completely remove the clot, increasing the procedure time and the potential for complications. Adding imaging to the stent retrieval procedure may reduce both the procedure time and complications. In FIGS. 8-11 , system 10 includes imaging probe 100 and treatment device 91. While treatment device 91 is shown as a stent retriever, other treatment devices are applicable (e.g., treatment device 91 selected from the group consisting of stent retrievers, embolic coils, embolic coil delivery catheters, stents, covered stents, stent delivery devices, aneurysm treatment grafts, aneurysm treatment graft delivery devices, flow diverters, balloon catheters, and combinations thereof). Imaging probe 100 and treatment device 91 are positioned within a blood vessel, such as a blood vessel in the neck or head. The imaging probe 100 and the treatment device 91 may be inserted into a single catheter (eg, the delivery catheter 50d shown).

[0226] The positioning of the optical assembly 130 and the resulting images ensure accurate placement of the treatment device 91 (e.g., placement of a stent retriever distal to the thrombus) and also ensure that the treatment is completed successfully (e.g., sufficient thrombus is removed), which can not only shorten the procedure time but also improve clinical outcomes.

[0227] In some embodiments, system 10 includes a delivery catheter 50a (e.g., a 6-8 French guide catheter, not shown) that can be positioned within a target vessel (e.g., an artery) using, for example, transfemoral access. In some embodiments, delivery catheter 50a includes a standard balloon guide catheter, for example, to prevent distal thrombus migration and enhance suction during thrombectomy. System 10 may further include a delivery catheter 50b (e.g., a 5-6 French flexible catheter, not shown) that serves as an intermediate catheter advanced through delivery catheter 50a to achieve distal access near the occluded portion of the vessel. System 10 may also include a third delivery catheter 50c, as shown, for example, a 0.021-0.027 inch microcatheter that crosses the thrombus. An angiographic procedure can be performed with the delivery catheter 50c to angiographically assess the proper location of the tip of the delivery catheter 50c (e.g., to estimate the location of the tip distal to the thrombus and the length of the clot). The treatment device 91 (e.g., a stent retriever as shown) is then released by retracting the delivery catheter 50c while holding the treatment device 91 in place. In some embodiments, the treatment device 91 needs to cover the entire length of the occlusion (e.g., when the stent portion opens) to achieve blood flow restoration.

[0228] In Figure 8, the distal portion of the delivery catheter 50c is positioned within a blood vessel (e.g., within the location of the blood vessel containing a thrombus). The stent portion of the treatment device 91 is placed in an undeployed, entrapped state within the distal portion of the delivery catheter 50c. In Figure 9, the delivery catheter 50c is retracted to deploy the stent portion of the treatment device 91 (e.g., to entangle a thrombus (not shown)). In Figure 10, the imaging probe 100 is advanced through the deployed stent portion of the treatment device 91. Image data may be collected during advancement. In Figure 11, the imaging probe 100 is retracted (the optical assembly 130 passes through the stent portion of the treatment device 91) as image data is collected, for example, to evaluate a procedure described herein.

[0229] In some embodiments, system 10 is configured and designed to provide control of torque applied proximally (e.g., to core 120) and rotational speed applied distally (e.g., to core 120 and / or optical assembly 130). This configuration has several advantages, including, but not limited to, compact size, low cost, and independence from tortuous paths proximal to the distal tip of imaging probe 100.

[0230] In some embodiments, system 10 is configured to provide precise rotational control (e.g., avoid undesirable rotational speed fluctuations of core 120 and / or optical assembly 130) through inertial damping, e.g., inertial damping that increases with rotational speed. This control can be achieved using a viscous fluid in contact with core 120 and / or optical assembly 130 (e.g., fluids 190a and / or 190b described herein), a fluid in contact with a mechanical load such as a vane-shaped microstructure, a mechanical load acting as a flywheel, and combinations thereof.

[0231] In some embodiments, the imaging probe 100 includes a shaft 110 having an OD of 0.016 inches or less (e.g., about 0.014 inches), includes structures independent of a guidewire, and is configured such that the shaft 110, core 120, and optical assembly 130 are retracted in unison using an external retraction (e.g., retraction assembly 220 described herein).

[0232] In some embodiments, the imaging probe 100 is configured to be advanced through a blood vessel to a target site, with or without the use of a microcatheter.

[0233] In some embodiments, the imaging probe 100 is configured such that the core 120 and optical assembly 130 are retracted into the shaft 110 during image data collection, such as by internal retraction using a purging medium (e.g., fluid 190 or other purging medium introduced between the core 120 and the shaft 110). In some embodiments, the introduced material is configured to provide an effect selected from the group consisting of refractive index matching, lubricity, bubble purging, and combinations thereof.

[0234] In some embodiments, the imaging probe 100 includes an Rx tip. In these embodiments, the imaging probe 100 may be configured such that the core 120 and optical assembly 130 are retracted within the shaft 110 during image data collection.

[0235] In some embodiments, the imaging probe 100 comprises a highly transportable, very small cross-section probe. In some embodiments, the shaft 110 comprises one or more optically transparent materials that provide a viewing portion 117, which is an optically transparent window disposed within the distal portion 119a of the shaft 110. The length of the viewing portion 117 may be between 1 mm and 100 mm (e.g., approximately 3 mm). In some embodiments, the length of the viewing portion 117 may be less than 50 mm (e.g., less than 20 mm or less than 15 mm) (e.g., a relatively short window in embodiments in which both the shaft 110 and the optical assembly 130 are simultaneously retracted during image data collection). The viewing portion 117 may comprise a material selected from the group consisting of nylon, nylon 12, nylon 66, and combinations of one or more of the foregoing. In some embodiments, at least a portion of the shaft 110 has a reinforced portion, including a reinforcing element, such as the stiffening portion (e.g., stiffening element 118 shown in FIG. 1 ). In some embodiments, the stiffening element 118 terminates proximal to the optical assembly 130 (e.g., proximal to the viewing portion 117 of the shaft 110). Alternatively, the stiffening element 118 may extend beyond the optical assembly 130, as shown in FIG. 2, and the setback pattern may be configured such that the optical path to and from the optical assembly 130 avoids the stiffening element 118. The stiffening element 118 may be configured to resist twisting of the distal portion 119a, for example, during rotation of the core 120. For example, the stiffening element 118 may include an element selected from the group consisting of a coil, a metal coil, a metal coil wrapped around a plastic such as PTFE, a tube, a metal tube, a metallic and / or plastic braid disposed within the wall of the shaft 110, and combinations thereof. In some embodiments, the shaft 110 includes a stiffening element 118 that includes a coil wound in a direction that makes the coil more likely to tighten upon rotation of the core 120 (e.g., more resistant to twisting of the shaft 110). In some embodiments, one or more portions of the stiffening element 118 contact a fluid (e.g., fluid 190 described herein) maintained within the shaft 110 such that torque forces applied to the stiffening element 118 by the fluid reduce twisting of the shaft 110.

[0236] In some embodiments, system 10 includes an integrated imaging probe 100 and one or more treatment devices (e.g., one or more treatment devices 91). For example, treatment device 91 may include a stent retriever, and system 10 is capable of simultaneously visualizing, in real time, one or more of the patient's anatomy (e.g., the patient's vessel wall and other tissue), the treatment device 91 (e.g., one or more struts of the treatment device 91), and / or thrombus or other occlusive material. Simultaneous visualization is associated with reduced procedure time and increased effectiveness.

[0237] In some embodiments, the system 10 is configured to apply proximal pressure to the imaging probe 100, for example, to keep the distal portion bubble-free or at least mitigate the formation of bubbles within one or more fluids 190 of the imaging probe 100.

[0238] As described herein, the imaging probe 100 may include a core 120 including a thin fiber optically coupleable at its distal end to an optical assembly 130 including a lens assembly. In some embodiments, a fluid interaction element (e.g., a coil or long winding, but not necessarily a torque wire) may be disposed immediately proximal to the optical assembly 130 (e.g., embedded within or within the wall of the shaft 110). In some embodiments, the shaft 110 may be filled with a low-viscosity fluid 190 to interact with the fluid interaction element to generate drag, for example. In contrast to conventional torque wires, the coil or other fluid interaction element is not wound, which increases viscous drag while still providing high-fidelity transmission of torque. The fluid 190 may be low-viscosity (e.g., having a viscosity of 1000 Cp or less) for easier filling and to reduce bubble artifacts created in high-viscosity solutions. The fluid interaction element may include an impeller (e.g., the impeller 182 described herein). The fluid interaction element has a cross-section of a shape selected from the group consisting of a non-circular cross-sectional portion of a portion of the shaft 110, for example, a polygonal cross-section of the lumen of the shaft 110, a protrusion into the lumen of the shaft 110, a recess in the inner diameter (i.e., inner wall) of the shaft 110, and a combination of one or more of these.

[0239] In some embodiments, the imaging probe 100 includes a shaped element (e.g., the impeller 182 described herein) that generates the viscous drag. This element may have a variety of shapes designed to maximize interaction with the internal fluid 190.

[0240] In some embodiments, the imaging probe 100 is constructed and designed such that viscous drag is created by mechanical friction between the portions that are rigidly coupled to the core 120 and in intimate contact with the walls of the shaft 110. Friction may be created by shear forces in a narrow annulus between the mechanical elements and the walls of the shaft 110, for example, when the shaft 110 is filled with fluid 190.

[0241] In some embodiments, the imaging probe 100 includes at least one fluid 190 contained by at least one sealing element (e.g., sealing element 116 and / or sealing element 151 described herein). The sealing elements 116 and / or 151 may be configured and designed to allow the core 120 to rotate within the sealed region while preventing the (viscous) fluid 190 from permeating through the seal. Some embodiments include two sealing elements 116a and 116b, one positioned just proximal to the optical assembly 130 and one positioned further distal, as shown in FIG. 17 . In these embodiments, the separation distance between the two sealing elements 116a and 116b and / or the viscosity of the trapped fluid 190 may be selected to generate sufficient torsional load when the core 120 rotates. In some embodiments, the two sealing elements 116a and 116b are spaced apart by a distance of 1 mm to 20 mm. In some embodiments, the viscosity of the fluid 190 is 10 Cp to 100 Cp.

[0242] In some embodiments, system 10 includes an imaging probe 100 and a console 200. Imaging probe 100 has a proximal end 111 and a distal end 119 and at least one lumen 112 extending between proximal end 111 and distal end 119. A core 120 is disposed within lumen 112, with the proximal end of core 120 optically and mechanically coupled to console 200 and the distal end of core 120 optically coupled to an optical assembly configured to collect image data within a body cavity.

[0243] In some embodiments, the imaging probe 100 includes an optical assembly 130 located at the distal end of the core 120, mechanically and optically connected to the core 120, which directs light toward an object being imaged (e.g., a thrombus, a vessel wall, tissue, and / or an implant) and collects return light from the imaged object. The imaging probe 100 may further include an inertial system (e.g., an impeller 182) located proximate the distal end of the core 120. The inertial system reduces undesirable rotational speed fluctuations that occur during rotation of the core 120. The inertial system may include a length of wound hollow-core cable, with the distal end of the core fixed to the core 120 just proximal to the optical assembly 130 and the proximal end unattached (e.g., not attached to the core 120). The inertial system may include a mechanical resistance element located in a distal region of the core 120 and may be in contact with the fluid 190 trapped within the lumen 112 of the shaft 110, creating mechanical resistance during rotation within the fluid 190.

[0244] In some embodiments, the imaging probe 100 includes a sealing element (e.g., a sealing element 151 described herein located within the lumen 112 of the shaft 110). The sealing element 151 may be configured to allow rotation of the core 120 while forming a substantially fluid-tight seal around the core 120 and the inner wall of the shaft 110. In some embodiments, the sealing element 151 is further configured as a mechanically resistant element. In some embodiments, the sealing element 151 is made of a hydrogel. In some embodiments, the sealing element 151 is made of an adhesive (e.g., a UV-curable adhesive) that bonds to the inner wall of the shaft 110 but not to the surface of the core 120. In some embodiments, the surface of the core 120 is configured to avoid bonding with the adhesive (e.g., a UV-curable adhesive). In some embodiments, the sealing element 151 is made of a compatible material, such as silicone rubber.

[0245] In some embodiments, the imaging system includes an imaging probe 100 and an imaging console, console 200. The imaging probe 100 has a proximal end 111, a distal end 119, and at least one lumen 112 extending between the proximal end 111 and the distal end 119. The imaging probe further includes a core 120 housed within the lumen 112 of the shaft 110, the core 120 optically and mechanically connected at its proximal end to the console 200, and optically connected at its distal end to an optical assembly 130 configured to collect image data within the body cavity. The optical assembly 130 is disposed at the distal end of the core 120 and configured to direct light at and collect return light from an object being imaged (e.g., a thrombus, a vascular cavity, tissue, and / or an implant).

[0246] In some embodiments, the imaging probe 100 includes the core 120 and one, two, or more inertial elements, such as an impeller 182 as described herein, attached to the optical assembly 130 and / or the core 120 (e.g., attached to a distal portion of the core 120). The impeller 182 may be configured to impart a rotational force to the core 120 when the core 120 is being drawn in (e.g., in the presence of a liquid, gel, or gaseous medium, such as a fluid 190), e.g., to reduce undesirable rotational speed fluctuations. The impeller 182 may have a turbine-like configuration.

[0247] In some embodiments, system 10 includes an imaging probe 100 and an imaging console, console 200. Imaging probe 100 has a proximal end 111, a distal end 119, and at least one lumen 112 extending between proximal end 111 and distal end 119. Imaging probe 100 further includes a rotatable optical core, core 120, housed within lumen 112 of shaft 110, with core 120 optically and mechanically coupled to console 200 at its proximal end and configured to collect image data from the body cavity at its distal end.

[0248] As described herein, the imaging probe 100 includes an optical assembly 130 disposed at the distal end of the core 120. The optical assembly 130 is mechanically and optically coupled to the core 120 and configured to direct light at and collect return light from the tissue object being imaged. The imaging probe 100 may further include a stiffening element or other stiffening element (e.g., stiffening element 118 described herein) embedded in the shaft 110 to increase stiffness while creating an effective optically transparent window (for scanning rotation and retraction). The stiffening element 118 may include a wire and / or stiffening member (e.g., a plastic stiffening member) embedded within the shaft 110. The stiffening element 118 may have a helical shape. As described above, the spiral shape of the stiffening element 118 and the retracting spiral rotation pattern of the optical assembly 130 are aligned, but may be offset by approximately 1 / 2 of the spiral of the stiffening element 118 during retraction of the optical assembly 130, allowing the imaging beam of the optical assembly 130 to pass between the spirals of the stiffener 118.

[0249] Referring to FIG. 12 , a side cross-sectional view of the distal portion of probe 100 is shown inserted into a blood vessel for placement of optical assembly 130 within a treatment device 91 (e.g., a stent deployment device, stent retriever, or other treatment device) consistent with the concepts of the present invention. Probe 100 includes shaft 110, core 120, optical assembly 130, lens 131, and reflector 132. These and other components of probe 100 may have similar configurations and designs as described above. In some embodiments, distal tip 119 has a shape and / or stiffness to enhance advancement of distal tip 119 through a blood vessel and / or one or more devices disposed therein. For example, distal tip 119 may have a bullet-shaped profile as shown in FIG. 12 . Alternatively or additionally, treatment device 91 may include a proximal portion (e.g., proximal end 91 a as shown) that may be configured to enhance delivery from proximal end 91 a to distal end 119. In some embodiments, probe 100 includes a spring tip, such as spring tip 104 described above.

[0250] Probe 100, and other components of system 10, may be configured to allow a clinician or other operator to "watch" (e.g., in real time) the collection of thrombus or other occlusive material into treatment device 91 to determine, for example, when to remove treatment device 91 and / or how to manipulate treatment device 91 (e.g., maneuver to remove treatment device 91 and / or reposition treatment device 91 to enhance treatment). The ability to observe the treatment can improve the effectiveness of the procedure (e.g., enhance thrombus removal) as well as avoid unnecessary wait times and other delays.

[0251] Referring to FIG. 13 , a side cross-sectional view of the distal portion of probe 100 is shown, consistent with the concepts of the present invention. Probe 100 includes shaft 110, lumen 112, core 120, optical assembly 130, lens 131, and reflector 132. These and other components of probe 100 may have similar configurations and designs as described above. In some embodiments, distal portion 119a of shaft 110 includes stiffening element 118a, shown in FIG. 13 , which is a reinforcing element. The inclusion of stiffening element 118a may allow the wall of shaft 110 surrounding optical assembly 130 to be thinner (e.g., thinner than the wall of a more proximal portion of shaft 110). Stiffening element 118a may include an optically transparent material, as described herein. Stiffening element 118a may be configured to provide columnar and / or torsional strength to shaft 110. In some embodiments, the probe 100 includes a lumen narrowing structure (e.g., the illustrated tube 114 disposed within the lumen 112 of the shaft 110). The tube 114 may adhesively or at least frictionally engage the inner wall of the shaft 110 or the outer surface of the core 120. In some embodiments, the tube 114 is simply a protrusion from the inner wall of the shaft 110 (e.g., a portion of the shaft 110). The tube 114 may be configured to provide a function selected from the group consisting of increasing the torsional strength of the shaft 110, increasing the column strength of the shaft 110, providing capillary action in the fluid surrounding the core 120 and / or the optical assembly 130, and combinations thereof. In some embodiments, the probe 100 includes the illustrated fluid 190a and / or fluid 190b, e.g., as described above. The fluids 190a and 190b may comprise similar or different fluids. In some embodiments, fluid 190a and / or fluid 190b comprise a low viscosity fluid, as described above. In some embodiments, fluid 190a and / or fluid 190b comprise a shear thinning fluid, as described above.

[0252] Referring to FIG. 14 , a schematic diagram of an imaging probe shown in a partially assembled state is shown, consistent with the concepts of the present invention. The probe 100 may have a first portion configured and designed as shown in FIG. 14 , including a connector 102 a, an outer shaft 110 a, and a spring tip 104. The probe 100 may further include a second portion, a connector 102 b, a torque shaft 110 b, a core 120, and an optical assembly 130. The outer shaft 110 a, the spring tip 104, the core 120, and the optical assembly 130, as well as other components of the probe 100, may have similar configurations and designs as those described above. The connector 102 b may have a similar configuration and design to the connector 102 described above, for example, to optically connect the probe 100 to the console 200. The connector 102 a may be configured to surround and mechanically engage the connector 102 b such that the connectors 102 a and / or 102 b are mechanically connected to the console 200.

[0253] The torque shaft 110b frictionally engages the core 120 (e.g., via adhesive) at least at a distal portion of the torque shaft 110b. The torque shaft 110b may be attached to the connector 102b via adhesive or other mechanical engagement (e.g., via a metal tube, not shown, such as a tube press-fit into the connector 102b). In some embodiments, the end of the torque shaft 110b is provided with a strain relief tube 121, as shown. The tube 121 may be configured to reduce kinking and / or increase adhesion between the torque shaft 110b and the core 120. The ID and / or OD of the tube 121 and the torque shaft 110b may be similar.

[0254] During assembly, torque shaft 110b, optical assembly 130, and core 120 are positioned within shaft 110a. Connector 102a can mate with connector 102b to maintain the relative positions of the two components.

[0255] The torque shaft 110b may comprise one or more plastic or metallic materials, such as when the torque shaft 110b comprises a braided torque shaft (e.g., a braid including at least stainless steel). The torque shaft 110b may have a length (e.g., approximately 49 cm) such that the distal end of the torque shaft 110b terminates a minimal distance away from the optical assembly 130. In some embodiments, the torque shaft 110b has a length such that it does not penetrate at all, or only a small portion of the torque shaft 110b penetrates, into the patient's body. In these embodiments, the retraction assembly 220 may be disposed and engaged with the shaft 110 at a location distal to the distal end of the retraction assembly 220.

[0256] 15A-15C, a series of cross-sectional side views of an imaging probe are shown at successive steps in the expansion of the shaft with an internal fluid, consistent with the concepts of the present invention. The probe 100 includes a connector 102, a shaft 110, a core 120, and an optical assembly 130. These and other components of the probe 100 may have similar configurations and designs as described above. The shaft 110 has a proximal portion 111a, a central portion 115, and a distal portion 119a. The probe 100 further includes a pressure assembly 183, which may include a valve 184, each of which may have a configuration and design similar to the analogous components described with reference to FIG. 7. The probe 100 may be configured such that the shaft 110 expands upon introducing fluid into the lumen 112 and / or increasing the pressure of the fluid within the lumen 112. For example, a first introduction of fluid 190 into lumen 112 and / or a first increase in the pressure of fluid 190 in lumen 112 (e.g., by pressurizing assembly 183) may be performed to expand proximal portion 111 a of shaft 110, as shown in FIG. 15A. Subsequently, a second introduction of fluid 190 into lumen 112 and / or a second increase in the pressure of fluid 190 in lumen 112 may be performed to expand central portion 115 of shaft 110, as shown in FIG. 15B. Next, a third introduction of fluid 190 into lumen 112 and / or a third increase in the pressure of fluid 190 in lumen 112 may be performed to expand distal portion 119 a of shaft 110, as shown in FIG. 15C. In some embodiments, expanding shaft 110 forms a space between the inner wall of shaft 110 and core 120 and / or between the inner wall of shaft 110 and optical assembly 130.

[0257] Referring to FIG. 16 , a side cross-sectional view of the distal portion of an imaging probe including distal markers positioned relative to the optical assembly is shown, consistent with the concepts of the present invention. The probe 100 includes a shaft 110, a core 120, an optical assembly 130, a lens 131, and a reflector 132. These and other components of the probe 100 may have similar configurations and designs. The shaft 110 has a proximal portion 111a (not shown), a distal portion 119a, and a distal tip 119. The probe 100 may include a functional element 133a, which may be positioned on or relative to the optical assembly 130 (e.g., positioned on or at a desired and / or known distance from the optical assembly 130). The functional element 133a is shown positioned distal to the optical assembly 130 at a distance determined by a connecting element, tubing 134 (e.g., heat shrink tubing or other plastic tubing). In some embodiments, functional element 133 a includes a sensor, transducer, or other functional element described herein. In some embodiments, functional element 133 a includes a visualization element, such as a radiopaque element, an ultrasound-visible element, and / or a magnetic-visible element. In some embodiments, functional element 133 a includes a visualization element used to locate optical assembly 130 on images generated by an imaging device (e.g., a fluoroscope, an ultrasound imager, or an MRI). The fixed position of functional element 133 a relative to optical assembly 130 eliminates alignment issues that may arise when functional element 133 a is located on shaft 110 or other components of probe 100 due to, for example, changes in dimensions or other relative position to optical assembly 130 over time (e.g., expansion or contraction due to temperature shifts). In some embodiments, the functional element 133a is attached to the optical assembly 130 via a connecting element, such as the tube 134 described above, where the tube 134 or other connecting element (e.g., the connecting element 137 described herein) is configured to prevent dimensional changes that are affected by changes in temperature.In some embodiments, the probe 100 includes a fixation element 136 (e.g., an adhesive such as a UV-curable adhesive) positioned immediately distal to the functional element 133a as shown in FIG. 16 and configured to maintain the position of the functional element 133a.

[0258] Probe 100 may include one or more elements (e.g., one or more of elements 122a, 122b, and 122c shown in FIG. 16 ) that create frictional engagement between shaft 110 and core 120 and / or simply reduce the space between shaft 110 and core 120, e.g., to reduce undesirable fluctuations in rotational speed as described herein. In some embodiments, probe 100 includes a band 122a, which is a compression element, disposed around and / or within shaft 110 to frictionally engage a portion of the inner wall of shaft 110 with core 120. Alternatively or additionally, shaft 110 may include one or more protrusions 122b (e.g., annular protrusions) that extend into frictional engagement with core 120. Alternatively or additionally, core 120 may include one or more protrusions 122c, each extending into frictional engagement with shaft 110. One or more of elements 122a, 122b, and / or 122c may be included, each configured to generate a shear force that applies a load to core 120 during rotation of core 120. In some embodiments, a fluid 190, such as a shear-thinning fluid described herein, is disposed between shaft 110 and core 120. In these embodiments, one or more of elements 122a, 122b, and / or 122c may include a space-reducing element configured to increase the shear-thinning properties of fluid 190 as core 120 rotates (i.e., by interacting with fluid 190 to increase the amount of viscosity reduction greater than would occur in the absence of one or more space-reducing elements 122).

[0259] Referring to FIG. 17 , a side cross-sectional view of the distal portion of an imaging probe including two sealing elements is shown, consistent with the concepts of the present invention. The probe 100 includes a shaft 110, a core 120, an optical assembly 130, a lens 131, a reflector 132, and a viewing portion 117; these and other components of the probe 100 may have similar configurations and designs as described above. The shaft 110 has a lumen 112, a proximal portion 111a (not shown), a distal portion 119a, and a distal tip 119. The probe 100 may further include a spring tip 104. The probe 100 may include a functional element 113 as shown or other functional elements described herein. The probe 100 of FIG. 17 includes two sealing elements: sealing element 116a (e.g., an O-ring surrounding the core 120) and sealing element 116b (e.g., an elastomeric disk). In some embodiments, fluid 190b is disposed within shaft 110 between sealing elements 116a, 116b, for example, as described above. Alternatively or additionally, a second fluid 190a is disposed within shaft 110 proximal to sealing element 116a. In some embodiments, a third fluid 190c (not shown) is disposed within shaft 110 distal to sealing element 116b. Fluids 190a-c may include similar or different fluids, as also described above.

[0260] 18, a side cross-sectional view of the distal portion of an imaging probe including a lens and a reflective element offset from multiple visible markers is shown, consistent with the concepts of the present invention. Probe 100 includes a shaft 110, a core 120, an optical assembly 130, a lens 131, and a reflector 132. These and other components of probe 100 may have a similar configuration and design as above. Shaft 110 has a lumen 112, a proximal portion 111a (not shown), a distal portion 119a, and a distal tip 119.

[0261] In some embodiments, reflector 132 may be located distal to lens 131 and connected via connecting element 137, as shown in FIG. 18 and described above.

[0262] In some embodiments, the probe 100 includes multiple visualization markers (e.g., four functional elements 123a shown in FIG. 18 ) that may be configured to provide a “ruler function” when visualized by a fluoroscope, ultrasound imager, or MRI (e.g., when the functional elements 123a include radiopaque, ultrasound-reflective, or magnetic markers, respectively). The functional elements 123a may include one or more visualization bands (e.g., one or more compressible bands and / or wire coils) frictionally engaged with the core 120. Alternatively or additionally, one or more functional elements 123a may be positioned on, within, and / or on the interior wall of the shaft 110. The functional elements 123a may be equally spaced and / or spaced apart by a known distance. In some embodiments, one or more functional elements 123a may be further configured as a sealing element (e.g., to provide a seal against contained fluids, such as one or more fluids 190 described herein) and / or as a rotational brake configured to reduce undesirable rotational speed changes of core 120 and / or optical assembly 130.

[0263] While preferred embodiments of the apparatus and methods have been described in relation to the environments in which they were developed, these are merely illustrative of the principles of the inventive concepts. Variations or combinations of the above assemblies, other embodiments, configurations, and methods of implementing the inventive concepts, and variations of aspects of the inventive concepts that are obvious to those skilled in the art, are intended to be included within the scope of the claims. Furthermore, where method or procedure steps are recited in this application in a particular order, it is possible, and even advantageous, in particular circumstances to vary the order in which some steps are performed, and it is not intended that the particular steps of a method or procedure claim set forth in the claims be construed as including a specified order unless such an order is expressly designated in the claims.

Claims

1. 1. An imaging system for a patient comprising an imaging probe, the imaging probe comprising: an elongate shaft adapted for insertion into a patient's body, the elongate shaft having a proximal end, a distal portion, and a lumen extending between the proximal end and the distal portion; a rotatable optical core having a proximal end and a distal end, the rotatable optical core configured to provide optical and mechanical connection to the interface unit; a probe connector disposed on a proximal end of the elongate shaft and surrounding at least a portion of the rotatable optical core; an optical assembly disposed within the distal portion of the elongate shaft proximate the distal end of the rotatable optical core and configured to direct light to tissue and collect reflected light from the tissue; a shear thinning fluid located within the distal portion of the elongate shaft. Imaging system.

2. the imaging probe further includes at least one space reduction element disposed between the elongate shaft and the rotatable optical core; the at least one spatial reduction element is configured to reduce variations in rotational speed of the rotatable optical core. The imaging system according to claim 1 .

3. the at least one space reducing element is disposed within at least a portion of the distal portion of the elongate shaft. The imaging system according to claim 2 .

4. the at least one space reducing element is configured to reduce fluctuations in the rotational speed by increasing the shear thinning of the shear thinning fluid. The imaging system according to claim 2 .

5. an outer diameter of the optical assembly that is greater than an inner diameter of at least a portion of the elongate shaft that is proximal to the optical assembly; The imaging system according to claim 1 .

6. and a retraction assembly configured and designed to simultaneously retract the elongate shaft and the optical assembly as the imaging probe collects image data from a region of interest. The imaging system according to claim 5 .

7. configured to generate a three-dimensional image upon retraction of the elongate shaft; The imaging system according to claim 1 .

8. configured to detect and / or quantify malapposition of a flow diverter implanted within a patient; The imaging system according to claim 1 .

9. configured to provide quantitative and / or qualitative information for use in determining the size of a flow diverter to be implanted within a patient and / or for positioning the flow diverter within the patient; The imaging system according to claim 1 .

10. The quantitative and / or qualitative information includes information about parameters selected from the group consisting of a location of perforator veins, a shape of perforator veins, a size of a neck, a mesh density of a flow diverter, and combinations thereof. The imaging system according to claim 4 .

11. configured to image a stent retriever positioned at least partially within a thrombus in a patient; The imaging system according to claim 1 .

12. The imaging device is configured to image at least one of thrombus not entangled in the stent retriever or thrombus not removed by the stent retriever. The imaging system according to claim 12.

13. configured to quantify a volume of a thrombus in a patient; The imaging system according to any one of claims 1 to 12.

14. The quantified thrombus includes thrombus selected from the group consisting of residual thrombus in an acute stroke, thrombus remaining after a thrombectomy procedure, thrombus present after flow diverter implantation, and combinations thereof. The imaging system according to claim 13.

15. configured to provide implantation site information; using the implantation site information to select a particular implantable device for implantation within the patient's body; The imaging system according to any one of claims 1 to 14.

16. further comprising the implantable device for implantation within a patient's body; the implantable device comprises a device selected from the group consisting of a stent, a flow diverter, and combinations thereof; The imaging system of claim 15.

17. the implantable device is selected based on an implantable device parameter selected from the group consisting of porosity, length, diameter, and combinations thereof; The imaging system of claim 15.

18. configured to provide porosity information for a device implanted within a patient's body; The imaging system according to any one of claims 1 to 17.

19. the porosity information includes the porosity of a portion of the implanted device that is positioned adjacent to a side branch of a blood vessel in which the implanted device is to be placed; The imaging system of claim 18.

20. the system is configured to provide the porosity information based on a wire diameter of the implantation device. The imaging system of claim 18.

21. The implantation device further comprises: the implantable device comprises a device selected from the group consisting of a stent, a flow diverter, and combinations thereof; The imaging system of claim 18.

22. and configured to provide information regarding implantation of the second device within the patient's body. The imaging system of claim 18.

23. configured to image at least one perforator artery of the patient; 23. The imaging system according to any one of claims 1 to 22.

24. The diameter of the at least one perforator artery is 50 μm or more.

24. The imaging system of claim 23.

25. further comprising at least one guide catheter; 25. The imaging system of any one of claims 1 to 24.

26. the at least one guide catheter comprises a microcatheter.

26. The imaging system of claim 25.

27. The inner diameter of the microcatheter is equal to or greater than 0.0165 inches and equal to or less than 0.027 inches.

27. The imaging system of claim 26.

28. The inner diameter of the microcatheter is equal to or greater than 0.021 inches and equal to or less than 0.027 inches.

27. The imaging system of claim 26.

29. The imaging probe is configured to reach the blood vessels of the brain.

29. The imaging system of any one of claims 1 to 28.

30. The inner diameter of the elongate shaft varies along the length of the shaft.

30. The imaging system of any one of claims 1 to 29.

31. the outer diameter of the elongated shaft is equal to or greater than 0.006 inches and equal to or less than 0.022 inches; 31. The imaging system of any one of claims 1 to 30.

32. The inner diameter of the elongated shaft is equal to or greater than 0.004 inches and equal to or less than 0.012 inches.

32. The imaging system of any one of claims 1 to 31.

33. the elongate shaft further having an intermediate section; an inner diameter of the distal portion of the elongate shaft that is greater than an inner diameter of the intermediate portion of the elongate shaft; 33. The imaging system of any one of claims 1 to 32.

34. the inner diameter of the distal portion of the elongate shaft is at least 0.002 inches larger than the inner diameter of the intermediate portion of the elongate shaft; 34. The imaging system of claim 33.

35. an outer diameter of the distal portion of the elongate shaft that is greater than an outer diameter of the intermediate portion of the elongate shaft; 34. The imaging system of claim 33.

36. the outer diameter of the distal portion of the elongate shaft is at least 0.001 inches greater than the outer diameter of the intermediate portion of the elongate shaft; 36. The imaging system of claim 35.

37. a wall thickness of the distal portion of the elongate shaft that is less than a wall thickness of the intermediate portion of the elongate shaft; 34. The imaging system of claim 33.

38. a distal portion of the elongate shaft comprising a stiffer material than an intermediate portion of the elongate shaft; 38. The imaging system of claim 37.

39. the distal portion of the elongate shaft includes a rapid exchange guidewire lumen; 39. The imaging system of any one of claims 1 to 38.

40. the distal portion of the elongate shaft has an optically transparent window; the optical assembly is disposed within the optically transparent window; 40. The imaging system of any one of claims 1 to 39.

41. the length of the optically transparent window is less than 20 mm; 41. The imaging system of claim 40.

42. the length of the optically transparent window is less than 15 mm; 42. The imaging system of claim 41.

43. the optically transparent window comprises a material selected from the group consisting of Pebax, Pebax 7233, PEEK, amorphous PEEK, polyimide, glass, sapphire, nylon 12, nylon 66, and combinations thereof; 41. The imaging system of claim 40.

44. the shaft having at least a first portion disposed proximate the optically transparent window; the first portion includes a braided shaft; 41. The imaging system of claim 40.

45. The shaft further includes a second portion disposed proximal to the first portion, the second portion comprises a metal tube; 45. The imaging system of claim 44.

46. a fluid disposed within the lumen of the elongate shaft; and a fluid interaction element disposed within the lumen and a distal portion of the elongate shaft; the fluid interaction element is configured to interact with the fluid to increase a load on the rotatable optical core during rotation of the rotatable optical core.

46. ​​The imaging system of any one of claims 1 to 45.

47. the imaging probe further includes a first sealing element positioned within the lumen of the elongate shaft; the first sealing element is disposed between the rotatable optical core and the elongate shaft and configured to slidingly engage the rotatable optical core and resist fluid flow around the sealing element; 47. The imaging system of any one of claims 1 to 46.

48. the first sealing element is disposed within a distal portion of the elongate shaft.

48. The imaging system of claim 47.

49. the imaging probe further includes a first fluid disposed proximate to the optical assembly and a second fluid disposed proximate to the rotatable optical core; the first sealing element is disposed between the first fluid and the second fluid; 49. The imaging system of claim 48.

50. the first fluid has a first viscosity; The viscosity of the second fluid is greater than the viscosity of the first fluid.

50. The imaging system of claim 49.

51. further comprising a second sealing element disposed between the rotatable optical core and the elongate shaft; the second sealing element is configured to slidingly engage the rotatable optical core and is further configured to resist fluid flow around the second sealing element; the imaging probe further including a fluid disposed between the first sealing element and the second sealing element; 48. The imaging system of claim 47.

52. The viscosity of the fluid disposed between the first sealing element and the second sealing element is 10 Cp or more and 100 Cp or less.

52. The imaging system of claim 51.

53. the first sealing element is disposed proximal to and adjacent to the optical assembly; The second sealing element is disposed distally of the first sealing element.

52. The imaging system of claim 51.

54. the rotatable optical core is configured and designed to rotate in a single direction; 54. The imaging system of any one of claims 1 to 53.

55. The rotatable optical core is configured and designed to rotate in two directions; 55. An imaging system according to any one of claims 1 to 54.

56. The outer diameter of the optical assembly is 80 μm or more and 500 μm or less.

56. An imaging system according to any one of claims 1 to 55.

57. the optical assembly includes a lens, a reflective element, and a connecting element, the connecting element positioning the reflective element relative to the lens; 57. An imaging system according to any one of claims 1 to 56.

58. the connecting element comprises an element selected from the group consisting of tubing, flexible tubing, heat shrink, an optically transparent arm, and combinations thereof; 58. An imaging system according to any one of claims 1 to 57.

59. The connecting element positions the reflective element at a distance of 0.01 mm or more and 3.0 mm or less from the lens.

58. The imaging system of claim 57.

60. the imaging probe further includes a fluid disposed within a lumen of the elongate shaft.

60. An imaging system according to any one of claims 1 to 59.

61. the fluid includes a first fluid disposed around the optical assembly and a second fluid disposed around the rotating optical core; 61. The imaging system of claim 60.

62. the first fluid has a first viscosity; the second fluid has a second viscosity greater than the first viscosity; 62. The imaging system of claim 61.

63. the second fluid is configured and designed to reduce fluctuations in the rotational speed of the rotatable optical core; 62. The imaging system of claim 61.

64. further comprising a sealing element disposed between the first fluid and the second fluid.

64. The imaging system of claim 63.

65. the fluid comprises a shear thinning fluid; 64. The imaging system of claim 63.

66. the fluid comprises a shear-thinning gel; 66. The imaging system of claim 65.

67. The fluid is configured to provide lubrication.

66. The imaging system of claim 65.

68. the fluid is configured to tend to keep the rotatable optical core centered on the elongate shaft during rotation of the rotatable optical core.

66. The imaging system of claim 65.

69. 66. The imaging system of claim 65, wherein the viscosity of the first fluid is equal to or greater than 10 Pa·S and equal to or less than 100,000 Pa·S.

70. The first fluid is －１ is configured to reduce the viscosity to a level of about 3 Pa S at a shear rate of 66. The imaging system of claim 65.

71. the fluid includes a first fluid and a second fluid; the second fluid is disposed within the shaft proximate the optical assembly; The first fluid is disposed within the shaft proximal to the second fluid.

61. The imaging system of claim 60.

72. the imaging probe further includes a torque shaft having a proximal end and a distal end; the torque shaft is fixedly attached to the rotatable optical core such that rotation of the torque shaft rotates the rotatable optical core; 72. The imaging system of any one of claims 1 to 71.

73. further comprising a retraction assembly configured and designed to retract at least one of the rotatable optical core or the elongate shaft; The distal end of the torque shaft is disposed proximal to the retraction assembly.

73. The imaging system of claim 72.

74. further comprising a rotation assembly configured and designed to rotate the rotatable optical core.

74. An imaging system according to any one of claims 1 to 73.

75. the rotating assembly rotates the rotatable optical core at a speed of 20 rps or more and 2500 rps or less; 75. The imaging system of claim 74.

76. the rotating assembly rotates the rotatable optical core at a speed of about 250 rps; 76. The imaging system of claim 75.

77. the rotating assembly rotates the rotatable optical core at speeds up to 25,000 rpm; 75. The imaging system of claim 74.

78. further comprising a retraction assembly configured and designed to retract at least one of the rotatable optical core or the elongate shaft.

78. An imaging system according to any one of claims 1 to 77.

79. the retraction assembly is configured and designed to retract both the rotatable optical core and the elongate shaft; 79. The imaging system of claim 78.

80. the retraction assembly is configured and designed to simultaneously retract the rotatable optical core and the elongate shaft; 80. The imaging system of claim 79.

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