System and method for detecting intravascular pressure fluctuations in blood vessels

Abstract

A catheter for detecting pressure fluctuations in a blood vessel includes an elongated body defining an elongated lumen therethrough, and a transducer disposed on the elongated body. The transducer is configured to output an electrical signal in response to a change in pressure.

Description

SYSTEM AND METHOD FOR DETECTING INTRAVASCULAR PRESSURE FLUCTUATIONS IN BLOOD VESSELSCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of, and priority to, U.S. Provisional Patent Application Serial No. 63 / 666,341 filed on July 1, 2024. The entire contents of the foregoing application are incorporated by reference herein.

[0002] Pressure fluctuations in blood vessels is an indicator of underlying pathology. For patients with pulsatile tinnitus, pressure fluctuations are responsible for sound generation either directly, or indirectly through development of vascular turbulence. Conditions such as pulsatile tinnitus are caused by irregular flow patterns in blood vessels near the cochlea, the sound sensing cavity of the inner ear. In addition, pressure fluctuations in blood vessels can contribute to the pathogenesis of various diseases through mechanisms such as vascular damage, organ strain, rupture of weak vessels, ischemia, and exacerbation of pre-existing conditions. This strain on the circulatory system and other organs may lead to diseases including atherosclerosis and other vascular narrowing processes, vessel dissection, aneurysms, and the like. In addition, cerebral venous insufficiency, or inadequate drainage of the blood in the brain through the venous system, may be indicated by pressure fluctuations and development of areas of high pressure in the cerebral venous system. Cerebral venous insufficiency can result in cognitive decline, difficulties with speech, and dizziness, among other neurological symptoms, and may further result in insufficient drainage of the brain lymphatics and potentially the development of dementia.

[0003] Thus, there is a need for systems and methods to detect and map pressure fluctuations in order to aid in diagnosing pulsatile tinnitus, cerebral venous insufficiency, and other vascular disorders.SUMMARY

[0004] Pulsatile tinnitus is a debilitating symptom that may be caused by a variety of vascular abnormalities, thus making the diagnosis very difficult. There are an estimated 3-5 million Americans that suffer from pulsatile tinnitus. In addition, vascular turbulence and abnormal wall sheer stress have been implicated in the development and progression of many vascular diseases. The most common of these vascular diseases is an atherosclerotic disease involving the internal carotid arteries of the neck, but also potentially involving the coronary arteries and intracranial arteries. Vascular turbulence is often involved in pathogenesis of cerebrovascular diseases such as atherosclerosis, dissections, aneurysm development, dural arteriovenous fistula, arteriovenous malformations, and the like.

[0005] In addition, cerebral venous insufficiency, or inadequate venous drainage of the brain, can result in myriad debilitating symptoms including cognitive decline, speech hesitancy, abnormal jerking movements of the limbs, dizziness, vertigo, imbalance, as well as insufficient absorption of brain lymphatics, and may be related to the development of dementia. Diagnosis of cerebral venous insufficiency is quite challenging, but fluctuations and buildup of pressure in the dural venous sinuses may be the most reliable indicators of cerebral venous insufficiency.

[0006] The present disclosure provides a system including a catheter having one or more transducers configured detect and map pressure fluctuations in blood vessels, which can serve as markers for the aforementioned diseases and facilitate early and accurate diagnosis. In particular, identifying pressure build-up and pressure fluctuations in the blood vessels may be used to predict development of disease, map out cerebral venous disease, and / or identify progression of a disease prior to anatomic changes by identifying the flow perturbation, which may lead to earlier, more effective, and safer therapies.

[0007] The catheter includes a circuit having a transducer disposed at a distal portion of the catheter. The circuit may be integrated, or may be external to the catheter. The transducer is configured to convert pressure wave aberrations generated by blood flow from within the blood vessels and generate electrical signals in response thereto. If integrated, the circuit may be secured using a waterproof sealant or other adhesives or any other suitable means, e.g., lamination. The integrated circuit includes one or more wires coupled thereto. The wires are disposed within the catheter and electrically couple the integrated circuit to an interface device having a driver circuit that is disposed outside of the patient. The interface device provides for locating a change in pressure within the patient’s blood vessels.

[0008] According to one embodiment of the present disclosure, a catheter for detecting intravascular pressure fluctuations in a blood vessel is described. The catheter includes: an elongated body defining an elongated lumen therethrough; and a first transducer disposed on the elongated body. The first transducer is configured to output an electrical signal in response to sound. The first transducer includes: an inner conductor disposed on an inner surface of the elongated body, piezo film disposed on an outer surface of the inner conductor, and an outer conductor disposed on an outer surface of the piezo film.

[0009] According to another embodiment of the present disclosure, a catheter for detecting intravascular pressure fluctuations in a blood vessel is described. The catheter includes: an elongated body defining an elongated lumen therethrough; and a first transducer disposed on the elongated body. The first transducer is configured to output an electrical signal in response to sound. The first transducer includes a membrane configured to deflect upon encountering a change in pressure.

[0010] According to one aspect of any of the above embodiments, the elongated body has an outer diameter from about 0.5 mm to about 2.5 mm.

[0011] According to another aspect of any of the above embodiments, the first transducer is disposed at a distal portion of the elongated body.

[0012] According to a further aspect of any of the above embodiments, the catheter further includes a second transducer. The first transducer may be disposed at a distal portion of the elongated body, and the second transducer may be disposed at a proximal portion of the elongated body.

[0013] According to yet another aspect of any of the above embodiments, the first transducer is disposed at a distal portion of the elongated body, and a distal end of the elongated body has greater flexibility than a proximal portion of the elongated body.

[0014] According to yet another embodiment of the present disclosure, a system for detecting pressure fluctuations in a blood vessel is described. The system includes a catheter having an elongated body defining an elongated lumen therethrough, and a first transducer disposed on an outer surface of the elongated body. The first transducer is configured to output an electrical signal in response to a change in pressure. The system also includes an interface device coupled to the first transducer, the interface device includes a controller configured to process the electrical signal and to record a location and a value of the change in pressure.

[0015] According to one aspect of the above embodiment, the elongated body has an outer diameter from about 0.5 mm to about 2.5 mm.

[0016] According to another aspect of the above embodiment, the first transducer includes: an inner conductor disposed on an inner surface of the elongated body; a piezo film disposed on anouter surface of the inner conductor; and an outer conductor disposed on an outer surface of the piezo film.

[0017] According to a further aspect of the above embodiment, the first transducer includes a membrane configured to deflect upon encountering a change in pressure.

[0018] According to yet another aspect of the above embodiment, the first transducer is disposed at a distal portion of the elongated body, and a distal end of the elongated body has greater flexibility than a proximal portion of the elongated body.

[0019] According to yet a further aspect of the above embodiment, the catheter further includes a second transducer. The first transducer may be disposed at a distal portion of the elongated body, and the second transducer may be disposed at a proximal portion of the elongated body.

[0020] According to another aspect of the above embodiment, the controller is further configured to determine a pressure gradient between the first transducer and the second transducer.

[0021] According to one aspect of the above embodiment, the controller is further configured to output the electrical signal through a visual output.

[0022] According to another aspect of the above embodiment, the interface device further includes a memory device configured to store a record of the change in pressure. The memory device is configured to store a database of a plurality of entries, each of which pertains to a record of the change in pressure.

[0023] Each entry of the plurality of entries includes at least one property describing the change in pressure, the at least one property selected from the group consisting of pressure, modified pressure, and location.

[0024] According to a further aspect of the above embodiment, the controller is further configured to automatically diagnose an abnormality of a blood vessel based on the plurality of entries of the database.

[0025] According to a further embodiment, a method for detecting pressure fluctuations in a blood vessel is described. The method includes: placing a catheter into a blood vessel, the catheter including an elongated body defining an elongated lumen therethrough; and measuring pressure at a transducer disposed on the elongated body, the transducer configured to output an electrical signal in response to a change in pressure. The method further includes processing the electrical signal at a controller to determine a value and a location of the pressure measurement.

[0026] According to one aspect of the above embodiment, the sound is measured while the catheter is being withdrawn from the blood vessel.

[0027] According to another aspect of the above embodiment, the change in pressure is measured while the catheter is being advanced into the blood vessel.

[0028] According to a yet another aspect of the above embodiment, the method further includes generating a pressure map to display the value and the location at least a portion of the pressure measurements.

[0029] According to another aspect of the above embodiment, the method further includes comparing the value and the location of the change in pressure at the controller to a database of a plurality of pressures and corresponding parameters to automatically diagnose an abnormality in the blood vessel. The abnormality may be at least one of an atherosclerosis, a fibromuscular dysplasia, a dissection, an aneurysm, a dural arteriovenous fistula, an arteriovenous malformation, a venous sinus stenosis, a sigmoid sinus diverticulum, a venous aneurysm, a jugular bulb diverticulum, a jugular vein stenosis, or a high riding jugular bulb.

[0030] According to another embodiment of the present disclosure, a catheter for detecting intravascular pressure fluctuations in a blood vessel is described. The catheter includes: an elongated body defining a first elongated lumen and a second elongated lumen therethrough; and a first transducer disposed on the elongated body. The first elongated lumen is disposed coaxially relative to and within the second elongated lumen. The first transducer is configured to output an electrical signal in response to sound. The first transducer includes a membrane configured to deflect upon encountering a change in pressure.

[0031] According to one aspect of the above embodiment, the first transducer is disposed on the second elongated lumen.

[0032] According to another aspect of the above embodiment, the catheter further includes a second transducer. The first transducer may be disposed at a distal portion of the elongated body, and the second transducer may be disposed at a proximal portion of the elongated body.

[0033] According to yet another aspect of the above embodiment, the second elongated lumen is configured to receive a fluid, and the fluid is configured to stiffen the catheter. The fluid may be instilled into the second elongated lumen using at least one of a valve or a flush port.

[0034] According to another embodiment, a method for detecting turbulence in a blood vessel is described. The method includes: placing a catheter into a blood vessel, the catheter including an elongated body defining an elongated lumen therethrough; and measuring a change in pressure at a transducer disposed on the elongated body, the transducer configured to output an electrical signal in response to a change in pressure. The method further includes comparing, at a controller, the measured change in pressure to a baseline pressure value; determining a presence of turbulent blood flow in the blood vessel based on the comparison between the measuredchange in pressure and the baseline pressure value; and outputting whether turbulence is present or absent within the blood vessel.

[0035] According to one aspect of the above embodiment, the change in pressure is measured at a sampling rate of between 1 and 100 Hz.

[0036] According to another aspect of the above embodiment, the method further includes, if turbulence is present within the blood vessel, determining a location of the turbulence within the blood vessel. The method may further include comparing the turbulence and the location of the turbulence at the controller to a database of a plurality of turbulences and corresponding parameters to automatically diagnose an abnormality in the blood vessel. The abnormality may be at least one of an atherosclerosis, a fibromuscular dysplasia, a dissection, an aneurysm, a dural arteriovenous fistula, an arteriovenous malformation, a venous sinus stenosis, a sigmoid sinus diverticulum, a venous aneurysm, a jugular bulb diverticulum, a jugular vein stenosis, or a high riding jugular bulb.

[0037] According to another embodiment, a guide wire assembly for detecting intravascular pressure fluctuations in a blood vessel is described. The guide wire assembly includes: a guide wire including a proximal portion and a distal portion, and a first transducer disposed on the guide wire. The first transducer is configured to output an electrical signal in response to a change in pressure.

[0038] According to one aspect of the above embodiment, the first transducer is disposed at the distal portion of the guide wire.

[0039] According to another aspect of the above embodiment, the guide wire assembly further includes a second transducer. The first transducer is disposed at the distal portion of the guide wire, and wherein the second transducer is disposed at the proximal portion of the guide wire.

[0040] According to yet another aspect of the above embodiment, the guide wire assembly further includes an interface device coupled to the first transducer. The interface device includes a controller configured to process the electrical signal and to record a location and a value of the change in pressure.

[0041] According to one aspect of the above embodiment, the guide wire assembly further includes a second transducer. The first transducer is disposed at the distal portion of the guide wire, and wherein the second transducer is disposed at the proximal portion of the guide wire.

[0042] According to another aspect of the above embodiment the controller is further configured to determine a pressure gradient between the first transducer and the second transducer.BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Embodiments of the present disclosure are described herein with reference to the accompanying drawings, wherein:

[0044] FIG. 1 is a two-dimensional cross-sectional velocimetry image of blood flow through a sigmoid sinus and a jugular vein;

[0045] FIG. 2 is a side, partially cross-sectional view of a catheter having a transducer disposed at a distal portion thereof according to one embodiment of the present disclosure;

[0046] FIG. 3 is a side, partially cross-sectional view of a catheter having a transducer disposed at a distal portion thereof according to another embodiment of the present disclosure;

[0047] FIG. 4 is a side, partially cross-sectional view of a catheter having a transducer disposed at each of a distal portion thereof and a proximal portion thereof according to another embodiment of the present disclosure;

[0048] FIG. 5 is a side, partially cross-sectional view of a dual-lumen catheter having a transducer disposed at a distal portion thereof according to another embodiment of the present disclosure;

[0049] FIG. 6 is a side, partially cross-sectional view of a guide wire having a transducer disposed at each of a distal portion thereof and a proximal portion thereof according to another embodiment of the present disclosure;

[0050] FIG. 7 is a schematic diagram of a system including a catheter with a transducer and a driver circuit for transducing pressure within a blood vessel according to the present disclosure; and

[0051] FIG. 8 is a chart describing a method of determining turbulence within a blood vessel according to the present disclosure.DETAILED DESCRIPTION

[0052] Embodiments of the present disclosure are described in detail with reference to the drawings, in which like reference numerals designate identical or corresponding elements in each of the several views. As used herein the term “proximal” refers to the portion of an implantable device that is closer to a delivery device, while the term “distal” refers to the portion that is farther from the delivery device.

[0053] The system and catheters according to the present disclosure may be used to measure sound in any blood vessel such as sigmoid sinus and internal jugular (SSIJ) vein shown in FIG. 1. However, this is an exemplary illustration used to show a particular pathology detectable by the catheter and system of the present disclosure. It should be understood that the present systems and catheters can be used to detect a variety of pathologies by measuring pressure in avariety of blood vessels. FIG. 1 shows a velocimetry image of irregular blood flow through S SIJ of a patient suffering from pulsatile tinnitus. In particular, FIG. 1 shows a sigmoid sinus 2, a jugular bulb 3, a jugular vein 4, a carotid artery 5, and blood flow 6 through the jugular vein 4. More specifically, blood flow 6 includes a vortex flow pattern originating in a superior aspect of the jugular bulb 3 and propagating down the descending jugular vein 4. The vortex flow pattern may be caused in part by pressure differences within different areas of vasculature. For example, as blood flows from an area of high pressure to an area of low pressure, it may flow in a turbulent manner, creating swirls and eddies. Among contributing to other potential maladies, it is believed that the blood flow 6, and in particular, its vortical shape, is a source of sound generation that is picked up by the cochlea and experienced by the patient as pulsatile tinnitus.

[0054] With reference to FIG. 2, a catheter 10 includes an elongated shaft 12 (i.e., outer jacket) defining an elongated inner lumen 14. The elongated shaft 12 may have an outer diameter from about 0.3 mm to about 2.5 mm, in embodiments from about 0.5 mm to about 2.5 mm, such that the catheter 10 is configured to pass into the jugular vein 4, the carotid artery 5, or other blood vessels near the cochlea. The inner lumen 14 may be configured to hold a wire or microwire. The catheter 10 includes a distal portion 16 and the catheter 10 may be of any suitable length for reaching the desired anatomical area. The elongated shaft 12 may be formed from a resilient flexible material, which may be a biocompatible polymer such as polyurethane. The elongated shaft 12 may be coupled to a hub (not shown) or any other structural elements that are disposed outside a patient during use to facilitate the use of the catheter 10.

[0055] In embodiments, the elongated shaft 12 may be formed as a single layer sheath, or a multi-layer sheath. The multi-layer sheath may be a laminated sheath in which each layer is formed from the same or different materials. In embodiments, the elongated shaft 12 may bebraided. Tn further embodiments, the elongated shaft 12 may include various coatings on an inner surface of the shaft 12, i.e., within the lumen 14, or on an outer surface of the shaft 12.

[0056] The catheter 10 includes a transducer 20, which may be embedded within or otherwise disposed on the elongated shaft 12. In embodiments, the transducer 20 may be disposed at the distal portion 16 of the catheter 10. The transducer 20 may be formed from the combination of an external conductor 22, an internal conductor 24, and a piezoelectric material 26. The external conductor 22 may be disposed on the outer surface of the elongated shaft 12 and may be formed from a conductive material such as a metal or polymer, or combinations thereof. The external conductor 22 may be formed from a biocompatible material. The internal conductor 24 may be formed from the same or substantially similar materials to the external conductor 22 but is instead disposed on the inner surface of the elongated shaft 12, that is, surrounding lumen 14. The external conductor 22 and the internal conductor 24 may be applied in one or more thin layers. For example, the external conductor 22 and the internal conductor 24 may be deposited onto the elongated shaft 12 or may be wound around the elongated shaft 12. The external conductor 22 and the internal conductor 24 are separated by the piezoelectric material 26. In particular, the piezoelectric material 26 may be composed of a piezoelectric film or strips that are braided or wound between the external conductor 22 and the internal conductor 24. As the catheter 10 moves within a blood vessel, pressure fluctuations induce a small amount of current in the transducer 20. To amplify the induced current, the transducer 20 may be coupled to an electrical lead which couples the transducer 20 to a driver circuit, such as an interface device 150 (FIG. 7).

[0057] With reference to FIG. 3, another embodiment of a catheter 30 is shown. The catheter 30 is substantially similar to the catheter 10 and includes an elongated shaft 32 defining a firstlumen 34a. The catheter 30 may have the same dimensions as the catheter 10 and may be formed from the same materials. The catheter 30 includes a transducer 40 disposed at a distal portion 36, specifically, a distal end 36a, of the elongated shaft 32. In this embodiment, the transducer 40 includes a membrane 42 and a sensor 44. The transducer 40 may be a part of the first lumen 34a or may be a part of the elongated shaft 32. The membrane 42 may be disposed within the elongated shaft 32, while the sensor may be disposed within the first lumen 34a. The membrane 42 may be a thin metal, a balloon, or any thin film material capable of deflecting in response to pressure fluctuations.

[0058] The sensor 44 may be located within the membrane 42. In aspects, the sensor 44 may be laminated into the catheter 30, such as within elongated shaft 32. The sensor 44 may be a strain gauge, or may be any other type of sensor configured to measure changes in resistance or impedance of the membrane 42. When membrane 42 deflects, the sensor 44 may induce current, which the transducer 40 may transmit to a driver circuit. The sensor 44 may instead be an optical sensor disposed on the elongated shaft 32. In the case that the sensor 44 is an optical sensor, deflections of the membrane 42 may cause sensor 44 to measure a distance to determine how much membrane 42 has moved. Deflections of the membrane 42 due to changes in pressure may be visually observed as well.

[0059] In aspects, a fluid, such as saline, may be introduced to the first lumen 34a to aid in the detection of changes in pressure. The fluid may be instilled using a valve (not shown), such as a rotating hemostatic valve, and the first lumen 34a may be sealed with a microwire passing therethrough. In further aspects, the catheter 30 may be a dual lumen catheter, and may include a flush port. The catheter 30 may include a second lumen 34b in addition to the first lumen 34a, such that the first lumen 34a is coaxially disposed within the second lumen 34b. The membrane42 may be located on an outer surface of the second lumen 34b, and the sensor 44 may be embedded within the membrane 42 or may be within the second lumen 34b. The fluid may be introduced within the second lumen 34b in order to flush the membrane 42 or to add fluid to the sensor 44. By adding fluid to fdl the second lumen 34b, the catheter 30 is rigidized, and therefore more receptive to changes in pressure. Thus, the transducer 40 may be more perceptive to changes in pressure within the blood vessel. In aspects, the catheter 30 may instead include a magnet wire transducer, which may deflect similarly to membrane 42 when encountering pressure wave perturbations.

[0060] Referring to FIG. 4, another embodiment of a catheter 50 is shown. The catheter 50 is substantially similar to catheter 10 and catheter 30 and includes an elongated shaft 52 defining a lumen 54. The catheter 50 may have the same dimensions as catheter 10 and catheter 30 and may be formed from the same materials. The catheter 50 includes multiple transducers for detecting changes in pressure in blood vessels. As shown, the catheter 50 may include a plurality of transducers 40, as previously described. A first transducer 40a may be disposed at a distal portion 56, specifically, a distal end 56a, of the elongated shaft 52. A second transducer 40b may be disposed at a proximal portion 58 of the elongated shaft 52, for example, a foot away from the first transducer 40a. Although transducers 40a, 40b are shown, it is contemplated that the catheter 50 may instead, or additionally, include one or more transducers 20 as previously described. Like the catheter 10 and the catheter 30, the catheter 50 may transmit electric signals from the first transducer 40a and the second transducer 40b to a driver circuit. Electric signals received from the second transducer 40b may be considered “baseline” pressure readings, and may be digitally subtracted from electric signals from the first transducer 40a. By filtering outpressure information from the second transducer 40b, deviations from standard flow may be more accurately located.

[0061] With reference to FIG. 5, another embodiment of a catheter 70 is shown. The catheter 70 is substantially similar to catheter 10, catheter 30, and catheter 50, and includes an elongated shaft 72. The elongated shaft 72 may define two lumens, a first lumen 74a for receiving a microwire, like catheter 10, catheter 30, and catheter 50, and a second lumen 74b for receiving wires or electrical leads for a transducer 80. The catheter may have the same general dimensions as catheter 10, catheter 30, and catheter 50, and may be formed from the same materials. A distal portion 76 of the elongated shaft 72, particularly a distal end 76a (i.e., a catheter tip), may be highly flexible and tapered for navigating through blood vessels. A proximal portion 78 of the elongated shaft 72 may be constructed from a stiffer material. In other embodiments, the distal end 76a may be blunt and angled, and the catheter 70 may be rotated to enter and exit blood vessels. The transducer 80 may be disposed on the outer surface of the elongated shaft 72 or within one of the first lumen 74a or the second lumen 74b. In embodiments, the transducer 80 may be coupled at the distal portion 76. The distal portion 76 may include a widened area 82 to accommodate the transducer 80 thereon. The transducer 80 may be coupled to the elongated shaft 72 using waterproof adhesive and / or the elongated shaft 72 may be laminated by a film to secure the transducer 80 to the elongated shaft 72. The transducer 80 may be any pressure transducer, such as a strain gauge. As previously noted, the transducer 80 may be coupled to an electrical lead which couples the transducer 80 to a driver circuit.

[0062] Referring to FIG. 6, in aspects, a guide wire assembly 90 is shown, which may be used as an alternative to the catheter-based systems of the present disclosure, while retaining similar functionality. Guide wire assembly 90 may include a guide wire 92, having a distal portion 96and a proximal portion 98. A first transducer 94a may be disposed at a distal end 96a of the distal portion 96 of guide wire 92. First transducer 94a may be integrated into guide wire 92 such that deflections at a location of first transducer 94a due to pressure changes, high pressure, and / or turbulence in the blood vessel may generate an electrical signal. For example, conductors and piezoelectric film may be disposed around guide wire 92 to act as first transducer 94a, similar to the manner described with reference to catheter 10 and transducer 20. First transducer 94a may otherwise be a strain gauge or other sensor capable of detecting pressure fluctuation and generating an electrical signal therefrom. First transducer 94a may be embedded into or adhered to guide wire 92, such as by waterproof sealant or other means. The electrical signal may then be transmitted to a driver circuit (FIG. 7) which may output a pressure value determined at a location of first transducer 94a in the blood vessel. Pressure values may be continuously determined and stored by the driver circuit in order to determine whether vascular pressure is high or turbulent at the location of the first transducer 94a.

[0063] It is contemplated that guide wire assembly 90 may additionally include a second transducer 94b disposed in the proximal portion 98 of guide wire 92 in order to determine a pressure differential between first transducer 94a and second transducer 94b. Second transducer 94b may be located a distance away from first transducer 94a, such as one foot away from first transducer 94a. Like first transducer 94a, second transducer 94b may be integrated into the guide wire 92 and may generate an electrical signal upon deflection of guide wire 92 caused by pressure fluctuations, high pressure areas, or turbulence in the blood vessel. Alternatively, second transducer 94b may a strain gauge or other sensor capable of generating an electrical signal to determine pressure, and may be embedded in or adhered to the proximal portion 98 of guide wire 92. The electrical signal from second transducer 94b may be transmitted to a drivercircuit which may determine a pressure value at a location of second transducer 94b in the blood vessel. A pressure differential may be determined between first transducer 94a and second transducer 94b to filter out deviations from standard flow. For example, electrical signals from second transducer 94b may be baseline pressure readings which may be subtracted from the electrical signals generated by first transducer 94a. In this manner, “noise” from standard blood flow may be filtered out and substantial deviations in pressure or areas of significantly higher pressure may be more precisely determined. Transducers in addition to transducers 94a, 94b may additionally be disposed on guide wire 92 and may generate electrical signals to determine pressure at various locations.

[0064] With reference to FIG. 7, a system 100 includes a catheter 110, which may be any of the above-disclosed devices, namely, the catheter 10 of FIG. 2, the catheter 30 of FIG. 3, the catheter 50 of FIG. 4, the catheter 70 of FIG. 5, or the wire of FIG. 6. The catheter 110 includes a transducer 118, which is representative of the transducer 20, 40, 60, or 80, which is shown schematically as having three leads 118a, 118b, 118c for connecting to ground, power, and output, respectively. The three leads 118a, 118b, 118c are coupled to an interface device 150, which includes a catheter connector 160, a power section 162, and a controller 164 coupled to a memory device 166.

[0065] The controller 164 may be any standard processor capable of executing data structures, data sequences, and / or computer programs. The memory device 166 may be any memory component associated with the controller 164 for storing information such as data structures, data sequences, and / or computer programs. The data structures, data sequences, and / or computer programs may be sequences of data structures or computer executable program code, and may be routines or subroutines within the structures or code.

[0066] The controller 164 may be any suitable processor (e.g., control circuit) adapted to perform the operations, calculations, and / or set of instructions described in the present disclosure including, but not limited to, a hardware processor, a field programmable gate array (FPGA), a digital signal processor (DSP), a central processing unit (CPU), a microprocessor, and combinations thereof. Those skilled in the art will appreciate that the processor may be substituted for by using any logic processor (e.g., control circuit) adapted to execute algorithms, calculations, and / or set of instructions described herein.

[0067] The controller 164 may be operably connected to the memory device 166, which may include one or more of volatile, non-volatile, magnetic, optical, or electrical media, such as readonly memory (ROM), random access memory (RAM), electrically-erasable programmable ROM (EEPROM), non-volatile RAM (NVRAM), or flash memory. The controller 164 and the memory device 166 may be any standard processor and memory component known in the art.

[0068] The interface device 150 may also include a display 168, one or more connectors 170 for coupling additional computing devices, and a visual output 172 for outputting the pressure measurements detected by the transducer 118. The visual output 172 may be a screen or a connector configured to couple to a visual device, e.g., a screen or a monitor. In aspects, the visual output 172 may be a device for rendering a physical copy of the pressure measurements detected by the transducer 118. For example, the visual output 172 may be a printer. The interface device 150 also includes a user interface 169, which may include one or more buttons, a touch screen, a keyboard, and the like, allowing for a user to control the interface device 150. The user interface 169 may be configured to activate or deactivate the transducer 118 as well as to view pressure readings and pressure fluctuations throughout a blood vessel. In aspects, pressure readings may be translated into pressure maps, displaying pressure measurementsand / or changes corresponding to locations within the blood vessel. Through the controller 164, the user interface 169 may communicate the pressure readings or the pressure maps to the visual output 172 for display or for generating a printed copy.

[0069] Pressure transducers such as the transducer 118 utilize a driver circuit in order to function, namely, output an electrical signal in response to an external physical stimulus. The transducer 118 may have an internal or an external power source. In embodiments, the transducer 118 may have a power source (e.g. a battery 119) disposed at the distal portion 16, 36, 56, or 76 of the catheter 10, 30, 50, or 70, or of the guide wire assembly 90. In embodiments, the power section 162, which may be an AC -DC power supply, supplies electrical energy to the transducer 118 and components of the interface device 150. The power section 162 is coupled to the transducer 118 through the leads 118a and 118b, which are disposed within the lumen 14, 34, 54, or 74b of the catheter 10, 30, 50, or 70, respectively. In the case of guide wire assembly 90, the leads 118a, 118b may be disposed within or otherwise attached to guide wire 92. The leads 118a and 118b terminate at the catheter connector 160.

[0070] In further embodiments, the transducer 118 may be coupled to the interface device 150 wirelessly, thus obviating the need to use electrical leads to couple the transducer 118 to the interface device 150. Wireless communication may be achieved via one or more wireless configurations, e.g., radio frequency, optical, Wi-Fi, Bluetooth (an open wireless protocol for exchanging data over short distances, using short length radio waves, from fixed and mobile devices, creating personal area networks (PANs), ZigBee® (a specification for a suite of high level communication protocols using small, low-power digital radios based on the IEEE 802.15.4-2003 standard for wireless personal area networks (WPANs)).

[0071] The transducer 118 is configured to output a digital signal corresponding to the sensed pressure as a signal through the lead 118c, which also terminates at the catheter connector 160. The digital signal is transmitted through the lead 118c to the controller 164, which receives and processes the digital signal and outputs the digital signal as a pressure reading to be displayed via the visual output 172. The controller 164 is also configured to store the digital signal within the memory device 166 and is further configured to transmit the signal for further processing and / or storage to an external computing device. The pressure reading may be output through the visual output 172 simultaneously while the digital signal is being stored.

[0072] During use, the catheter 10 is inserted in the arterial or venous system using conventional techniques. The insertion point may be anywhere in the body. In embodiments, a transvenous via a femoral or jugular approach may be used. The catheter 10 may be advanced into, or near a blood vessel where blood pressure fluctuations are suspected based on a patient’s symptoms or otherwise. In embodiments, the catheter 10 may be advanced into a blood vessel near the cochlea, such as the jugular vein 4 and the carotid artery 5 (FIG. 1). Pressure readings may be taken by the transducer 20 of the catheter 10 to locate an area having the largest fluctuation in pressure. The catheter 10 may be moved near this area of the blood vessel and further pressure readings may be taken to confirm the location which is the likeliest cause of the patient experiencing pulsatile tinnitus or other ailment.

[0073] Detection of the largest variation in pressure may be determined by the controller 164. In particular, the controller 164 continuously receives the electrical signal from the transducer 1 18 and determines a value of the electrical signal corresponding to a pressure. The controller 164 may store the value, at least temporarily, and compare the most recent value to a previously stored value at a prior time period, and may additionally store a difference between the value andthe previously stored value. The comparison of values may be done at a frequency from about 100 milliseconds to about 1 second. Thus, if there is a plurality of values having a decreasing pressure difference, then the controller 164 determines that the location of pressure fluctuation was identified. The location of the pressure differential may be determined by correlating the instance at which the largest difference was recorded with the insertion distance of the catheter 10.

[0074] The catheter 10 may also be used while being withdrawn. Initially, the catheter 10 is positioned at a distal most portion of a blood vessel and the catheter 10 is then moved in a proximal direction, namely, toward the insertion site. At regular intervals during the withdrawal of the catheter 19, pressure is recorded, measured, and analyzed by the interface device 150. The location at which the transducer 18 recorded a value having the largest pressure difference may be determined by the controller 164 as described above. The catheter 10 may also record and store pressure at regular intervals in order to visually map out pressure measurements throughout a blood vessel. The catheters 30 and 70 may be used in a similar manner as the catheter 10, in particular, the catheters 30 and 70 may be used to measure pressure while being advanced and / or withdrawn through the blood vessel.

[0075] The catheter 50 may be used in a similar manner as the catheter 10, but a pressure reading is taken at both the first transducer 20a, 40a and the second transducer 20b, 40b. For each pressure reading, the controller 164 may determine a modified pressure reading by subtracting a value detected by the second transducer 20b, 40b from a value detected by the first transducer 20a, 40a, to remove baseline flow information. The modified pressure reading may be stored and associated with a location of the first transducer 20a, 40a by the controller 164 in the creation of a pressure map of the blood vessel. In aspects, the controller 164 may determine apressure gradient between the first transducer 20a, 40a and the second transducer 20b, 40b. From a plurality of pressure readings taken at the first transducer 20a, 40a and the second transducer 20b, 40b, the controller 164 may determine a first transducer mean pressure reading and a second transducer mean pressure reading, and may subtract the second transducer mean pressure reading from the first transducer mean pressure reading to calculate the pressure gradient. It is contemplated that the controller 164 may also determine a peak pressure difference and a trough pressure difference between the first transducer 20a, 40a and the second transducer 20b, 40b. The controller 164 may determine the peak pressure difference by subtracting a maximum pressure reading taken from the second transducer 20b, 40b from a maximum pressure reading taken from the first transducer 20a, 40a. The controller may determine the trough pressure difference by subtracting a minimum pressure reading taken from the second transducer 20b, 40b from a minimum pressure reading taken from the first transducer 20a, 40a.

[0076] The interface device 150 is also configured to record the signals from the transducers 20, 40, 60, and 80 of the catheters 10, 30, 50, and 70, respectively. The memory device 166 stores each of the recorded signals in a database as a pressure value entry. Each entry corresponds to the recorded pressure value and includes a location as well as the underlying cause for the pressure difference. Such causes include, but are not limited to, atherosclerotic disease in an artery, venous sinus stenosis, dural arteriovenous fistula, and combinations thereof.

[0077] The database of pressure values that are recorded by the interface device 150 and the associated diagnoses and other properties allow the interface device 150 to automatically diagnose future patients. For example, a recorded pressure value may be compared to one or more pressure value entries stored in the database. A diagnosing tool may carry out thecomparison, and may cause the interface device 150 to provide an indication of a potential arterial cause of the change in pressure captured by the recorded pressure value or an abnormal connection between one or more blood vessels causing the change in pressure captured by the recorded pressure value. Arterial causes and abnormal connections between one or more blood vessels may include atherosclerosis, fibromuscular dysplasia, dissection, dural arteriovenous fistula, arteriovenous malformation, venous sinus stenosis, sigmoid sinus diverticulum, aneurysm or venous aneurysm, jugular bulb diverticulum, jugular vein stenosis, a high riding jugular bulb, and the like. Pressure changes due to these causes may result in a risk of stroke or bleeding in the brain, requiring a patient to undergo a diagnostic cerebral angiogram or other diagnostic procedure. The interface device 150 may include a means for uploading recorded pressure values and pressure value entries to an electronic medical record database.

[0078] The interface device 150, and in aspects, the diagnosing tool of the interface device 150, may use recorded pressure values to determine whether blood flow within a blood vessel is turbulent. Blood flow is typically laminar, flowing in smooth layers with predictable velocity and pressure. Turbulent blood flow is described as a disorganized movement of blood within a blood vessel, characterized by unpredictable fluctuations in velocity and pressure. Turbulent blood flow may result in increased stress on blood vessels as well as an increased risk of blood clot formation.

[0079] FIG. 8 describes a method 200 for determining turbulence, or high frequency pressure changes between four-hundred and two-thousand hertz (Hz), within a blood vessel. At step 210, a catheter, such as any of catheters 10, 30, 50, and 70, is placed into the blood vessel and pressure signals from a transducer, such as any of transducers 20, 40, 60, and 80, are measured. The pressure signals may be measured and recorded to the interface device 150 at a samplingrate of between one hertz to one hundred Hz. The measured pressure signals may be processed by interface device 150 to determine a pressure value, which at step 220, may be compared to a baseline pressure value. In comparing the measured pressure signals to the baseline pressure value, a difference may be determined. At step 230, the difference may be used to determine whether turbulence is present in the blood vessel. For example, if large, irregular pressure changes which follow no pattern are present, this may indicate turbulence. A location of turbulent blood flow may be determined as well. The presence and location of turbulence may be stored in a database as turbulence entries. At step 240, the interface device 150 may output to a user whether turbulence is present in the blood vessel, and if so, where. The output may appear using the visual output 172.

[0080] It is contemplated that, similar to the description above with reference to the diagnosing tool, the interface device 150 or diagnosing tool of the interface device 150 may output a potential cause of the turbulent blood flow within the blood vessel. Based on a comparison between the measured pressure signal and one or more turbulence entries stored in the database, the interface device 150 may discern whether an arterial cause or an abnormal connection between one or more blood vessels is a cause of the turbulent blood flow. The interface device 150 may output a type of arterial cause or abnormal connection, and may also indicate whether a patient may need to undergo a further diagnostic process. As mentioned earlier, the interface device 150 may include a means for uploading indications of turbulence, including locations of turbulence within the blood vessel, to an electronic medical record database.

[0081] It is envisioned that there will be an ongoing training of the interface device 150 using artificial intelligence after the initial database is developed until diagnostic accuracy is achieved. The terms “artificial intelligence,” “data models,” or “machine learning” may include, but are notlimited to, neural networks, convolutional neural networks (CNN), recurrent neural networks (RNN), generative adversarial networks (GAN), Bayesian Regression, Naive Bayes, nearest neighbors, least squares, means, and support vector regression, among other data science and artificial science techniques.

[0082] A neural network may be used to train the diagnosing tool. In various embodiments, the neural network may include a temporal convolutional network, with one or more fully connected layers, or a feed forward network. In various embodiments, training of the neural network may happen on a separate system, e.g., graphic processor unit (“GPU”) workstations, high performing computer clusters, etc., and the trained diagnosing tool would then be deployed on the interface device 150. In further embodiments, training of the neural networks may happen locally, e g., on the interface device 150. After training, the diagnosing tool may be a software application that is stored in the memory device 166 and is executable by the controller 164 to diagnose a potential cause of the pressure variation based on the location of the pressure variation in the blood vessel.

[0083] The catheters and system according to the present disclosure may also be used to diagnose a variety of other blood vessel abnormalities that result from changes in blood pressure. Fluctuations in blood pressure are often involved in pathogenesis of cerebrovascular diseases such as, atherosclerosis, dissections, aneurysm development, dural arteriovenous fistula, arteriovenous malformations, and the like.

[0084] The catheters and system according to the present disclosure would facilitate early and accurate diagnosis by precisely localizing pressure variation in blood vessels. In particular, identifying pressure differentials in the blood vessels may be used to predict development of disease and / or identify progression of a disease prior to anatomic changes by identifying the flowperturbation, which may lead to earlier and safer therapies. This may be done by comparing the recorded pressure readings to prior pressure readings stored in a database as described above.

[0085] Alternate embodiments may be devised without departing from the spirit or the scope of the present technology. Additionally, well-known elements of embodiments of the systems, apparatuses, and methods have not been described in detail or have been omitted so as not to obscure the relevant details of the systems, apparatuses, and methods.

[0086] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. The terms “comprises,” “comprising,” or any other variation thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by “comprises ... a” does not, without more constraints, preclude the existence of additional identical elements in the process, method, article, or apparatus that comprises the element. The terms “including” and / or “having,” as used herein, are defined as comprising (i.e., open language). The terms “a” or “an”, as used herein, are defined as one or more than one. The term “plurality,” as used herein, is defined as two or more than two. The term “another,” as used herein, is defined as at least a second or more. The description may use the terms "embodiment" or "embodiments," which may each refer to one or more of the same or different embodiments.

[0087] When the terms “coupled” and “connected,” along with their derivatives, are used, these terms are not intended as synonyms for each other. For example, “connected” may be used to indicate that two or more elements are in direct physical or electrical contact with each other. “Coupled” may mean that two or more elements are in direct physical or electrical contact (e.g.,directly coupled) or that two or more elements are not in direct contact with each other but yet still cooperate or interact with each other (e.g., indirectly coupled).

[0088] For the purposes of the description, a phrase in the form “A / B” or in the form “A and / or B” or in the form “at least one of A and B” means (A), (B), or (A and B), where A and B are variables indicating a particular object or attribute. When used, this phrase is intended to and is hereby defined as a choice of A or B or both A and B, which is similar to the phrase “and / or”. Where more than two variables are present in such a phrase, this phrase is hereby defined as including only one of the variables, any one of the variables, any combination of any of the variables, and all of the variables, for example, a phrase in the form “at least one of A, B, and C” means (A), (B), (C), (A and B), (A and C), (B and C), or (A, B and C).

[0089] Relational terms such as first and second, top and bottom, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. The description may use perspective-based descriptions such as up / down, back / front, top / bottom, and proximal / distal. Such descriptions are merely used to facilitate the discussion and are not intended to restrict the application of disclosed embodiments. Various operations may be described as multiple discrete operations in turn, in a manner that may be helpful in understanding embodiments; however, the order of description should not be construed to imply that these operations are order dependent.

[0090] As used herein, the term "about" or “approximately” applies to all numeric values, whether or not explicitly indicated. These terms generally refer to a range of numbers that one of skill in the art would consider equivalent to the recited values (i.e., having the same function or result). In many instances these terms may include numbers that are rounded to the nearestsignificant figure. As used herein, the terms “substantial” and “substantially” means, when comparing various parts to one another, that the parts being compared are equal to or are so close enough in dimension that one skill in the art would consider the same. Substantial and substantially, as used herein, are not limited to a single dimension and specifically include a range of values for those parts being compared. The range of values, both above and below (e.g., or greater / lesser or larger / smaller), includes a variance that one skilled in the art would know to be a reasonable tolerance for the parts mentioned.

[0091] Various embodiments of the systems, apparatuses, and methods have been described, and in many of the different embodiments many features are similar. To avoid redundancy, repetitive description of these similar features may not be made in some circumstances. It shall be understood, however, that description of a first-appearing feature applies to the later described similar feature and each respective description, therefore, is to be incorporated therein without such repetition.

[0092] From the foregoing, it will be appreciated that specific embodiments of the disclosure have been described herein for purposes of illustration, but that various modifications may be made without deviating from the scope of the disclosure. Accordingly, the disclosure is not limited except as by the appended claims.

Claims

1. WHAT IS CLAIMED IS:

1. A catheter for detecting intravascular pressure fluctuations in a blood vessel, the catheter comprising: an elongated body defining an elongated lumen therethrough; and a first transducer disposed on the elongated body, the first transducer configured to output an electrical signal in response to a change in pressure, wherein the first transducer includes: an inner conductor disposed on an inner surface of the elongated body, a piezo film disposed on an outer surface of the inner conductor, and an outer conductor disposed on an outer surface of the piezo film.

2. The catheter according to claim 1, wherein the elongated body has an outer diameter from about 0.5 mm to about 2.5 mm.

3. The catheter according to claim 1, wherein the first transducer is disposed at a distal portion of the elongated body.

4. The catheter according to claim 1, further comprising a second transducer, wherein the first transducer is disposed at a distal portion of the elongated body, and wherein the second transducer is disposed at a proximal portion of the body.

5. The catheter according to claim 1, wherein the first transducer is disposed at a distal portion of the elongated body, and wherein a distal end of the elongated body has greater flexibility than a proximal portion of the elongated body.

6. A catheter for detecting intravascular pressure fluctuations in a blood vessel, the catheter comprising: an elongated body defining a first elongated lumen therethrough; and a first transducer disposed on the elongated body, the first transducer configured to output an electrical signal in response to a change in pressure, wherein the first transducer includes a membrane configured to deflect upon encountering a change in pressure.

7. The catheter according to claim 6, wherein the elongated body has an outer diameter from about 0.5 mm to about 2.5 mm.

8. The catheter according to claim 6, wherein the first transducer is disposed at a distal portion of the elongated body.

9. The catheter according to claim 6, further comprising a second transducer, wherein the first transducer is disposed at a distal portion of the elongated body, and wherein the second transducer is disposed at a proximal portion of the elongated body.

10. The catheter according to claim 6, wherein the first transducer is disposed at a distal portion of the elongated body, and wherein a distal end of the elongated body has greater flexibility than a proximal portion of the elongated body.

11. A system for detecting pressure fluctuations in a blood vessel, the system comprising: a catheter including: an elongated body defining an elongated lumen therethrough; and a first transducer disposed on an outer surface of the elongated body, the first transducer configured to output an electrical signal in response to a change in pressure; and an interface device coupled to the first transducer, the interface device including a controller configured to process the electrical signal and to record a location and a value of the change in pressure.

12. The system according to claim 11, wherein the elongated body has an outer diameter from about 0.5 mm to about 2.5 mm.

13. The system according to claim 11, wherein the first transducer includes: an inner conductor disposed on an inner surface of the elongated body; a piezo film disposed on an outer surface of the inner conductor; and an outer conductor disposed on an outer surface of the piezo film.

14. The system according to claim 11, wherein the first transducer includes a membrane configured to deflect upon encountering a change in pressure.

15. The system according to claim 1 1, wherein the first transducer is disposed at a distal portion of the elongated body, and wherein a distal end of the elongated body has greater flexibility than a proximal portion of the elongated body.

16. The system according to claim 11, wherein the catheter further comprises a second transducer, wherein the first transducer is disposed at a distal portion of the elongated body, and wherein the second transducer is disposed at a proximal portion of the elongated body.

17. The system according to claim 16, wherein the controller is further configured to determine a pressure gradient between the first transducer and the second transducer.

18. The system according to claim 11, wherein the controller is further configured to output the electrical signal through a visual output.

19. The system according to claim 11, wherein the interface device further includes a memory device configured to store a record of the change in pressure.

20. The system according to claim 19, wherein the memory device is configured to store a database of a plurality of entries, each of which pertains to a record of the change in pressure.

21. The system according to claim 20, wherein each entry of the plurality of entries includes at least one property describing the change in pressure, the at least one property selected from the group consisting of pressure, modified pressure, and location.

22. The system according to claim 21, wherein the controller is further configured to automatically diagnose an abnormality of a blood vessel based on the plurality of entries of the database.

23. A method for detecting pressure fluctuations in a blood vessel, the method comprising: placing a catheter into a blood vessel, the catheter including an elongated body defining an elongated lumen therethrough; measuring pressure at a transducer disposed on the elongated body, the transducer configured to output an electrical signal in response to a change in pressure; and processing the electrical signal at a controller to determine a value and a location of the pressure measurement.

24. The method according to claim 23, wherein the pressure is measured while the catheter is being withdrawn from the blood vessel.

25. The method according to claim 23, wherein the pressure is measured while the catheter is being advanced into the blood vessel.

26. The method according to claim 23, further generating a pressure map to display the value and the location of at least a portion of the pressure measurements.

27. The method according to claim 23, further comprising: comparing the value and the location of the pressure at the controller to a database of a plurality of pressures and corresponding parameters to automatically diagnose an abnormality in the blood vessel.

28. The method according to claim 27, wherein the abnormality is at least one of an atherosclerosis, a fibromuscular dysplasia, a dissection, an aneurysm, a dural arteriovenous fistula, an arteriovenous malformation, a venous sinus stenosis, a sigmoid sinus diverticulum, a venous aneurysm, a jugular bulb diverticulum, a jugular vein stenosis, a cerebral venous insufficiency, or a high riding jugular bulb.

29. A catheter for detecting intravascular pressure fluctuations in a blood vessel, the catheter comprising: an elongated body defining a first elongated lumen and a second elongated lumen therethrough, wherein the first elongated lumen is disposed coaxially relative to and within the second elongated lumen; and a first transducer disposed on the elongated body, the first transducer configured to output an electrical signal in response to a change in pressure, wherein the first transducer includes a membrane configured to deflect upon encountering a change in pressure.

30. The catheter according to claim 29, wherein the first transducer is disposed on the second elongated lumen.31 . The catheter according to claim 29, further comprising a second transducer, wherein the first transducer is disposed at a distal portion of the elongated body, and wherein the second transducer is disposed at a proximal portion of the elongated body.

32. The catheter according to claim 29, wherein the second elongated lumen is configured to receive a fluid to stiffen the catheter.

33. The catheter according to claim 32, wherein the fluid is instilled into the second elongated lumen using at least one of a valve or a flush port.

34. A method for detecting turbulence in a blood vessel, the method comprising: placing a catheter into a blood vessel, the catheter including an elongated body defining an elongated lumen therethrough; measuring a change in pressure at a transducer disposed on the elongated body, the transducer configured to output an electrical signal in response to a change in pressure; comparing, at a controller, the measured change in pressure to a baseline pressure value; determining a presence of turbulent blood flow in the blood vessel based on the comparison between the measured change in pressure and the baseline pressure value; and outputting whether turbulence is present or absent within the blood vessel.

35. The method according to claim 34, wherein the change in pressure is measured at a sampling rate of between 1 and 100 Hz.

36. The method according to claim 34, further comprising, if turbulence is present within the blood vessel, determining a location of the turbulence within the blood vessel.

37. The method according to claim 36, further comprising, if turbulence is present within the blood vessel, comparing the turbulence and the location of the turbulence at the controller to a database of a plurality of turbulences and corresponding parameters to automatically diagnose an abnormality in the blood vessel.

38. The method according to claim 37, wherein the abnormality is at least one of an atherosclerosis, a fibromuscular dysplasia, a dissection, an aneurysm, a dural arteriovenous fistula, an arteriovenous malformation, a venous sinus stenosis, a sigmoid sinus diverticulum, a venous aneurysm, a jugular bulb diverticulum, a jugular vein stenosis, or a high riding jugular bulb.

39. A guide wire assembly for detecting intravascular pressure fluctuations in a blood vessel, the guide wire assembly comprising: a guide wire including a proximal portion and a distal portion; and a first transducer disposed on the guide wire, wherein the first transducer is configured to output an electrical signal in response to a change in pressure.

40. The guide wire assembly according to claim 39, wherein the first transducer is disposed at the distal portion of the guide wire.41 . The guide wire assembly according to claim 39, further comprising a second transducer, wherein the first transducer is disposed at the distal portion of the guide wire, and wherein the second transducer is disposed at the proximal portion of the guide wire.

42. The guide wire assembly according to claim 39, further comprising an interface device coupled to the first transducer, the interface device including a controller configured to process the electrical signal and to record a location and a value of the change in pressure.

43. The guide wire assembly according to claim 42, wherein the guide wire assembly further comprises a second transducer, wherein the first transducer is disposed at the distal portion of the guide wire, and wherein the second transducer is disposed at the proximal portion of the guide wire.

44. The guide wire assembly according to claim 43, wherein the controller is further configured to determine a pressure gradient between the first transducer and the second transducer.

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