Intravascular imaging longitudinal display vessel path correction

Abstract

The invention provides methods and systems for correcting translational distortion in a medical image of a lumen of a biological structure. The method facilitates vessel visualization in intravascular images (e.g. IVUS, OCT) used to evaluate the cardiovascular health of a patient. Using the methods and systems described herein it is simpler for a provider to evaluate vascular imaging data, which is typically distorted due to cardiac vessel-catheter motion while the image was acquired.

Description

[0001]2024PF00044 Intravascular Imaging Longitudinal Display Vessel Path Correction BACKGROUND Medical imaging is commonly used to evaluate various biological structures of a patient.A common type of imaging system is for example optical coherence tomography(OCT) or intravascular ultrasound (IVUS). Those types of systems generally acquireimages of an inside of an anatomical structure having a lumen, for example a blood vessel orother similar vasculature. Typically, such medical imaging systems include an imaging body that is pulledback (or pushed forward) inside a blood vessel. As the imaging body is pulled back,intravascular imaging recordings create a series of tomograms along the length of the blood vessel. A longitudinal display is created, which is a view of the blood vessel as if all of the tomograms were stacked and then sliced down the middle. The longitudinal display can be rotated at different angles depending on the angle of the slice through the stack of tomograms,but always centered around the imaging body which is at the center of each tomogram andtherefore always runs along the central axis of the longitudinal display. Because the imaging body is usually not centered within the blood vessel, there can be several things that make the longitudinal display difficult to understand. Cardiac motion causesthe appearance of “peaks” in the longitudinal display due to blood vessel motion relative to theimaging body. During a pullback, the imaging body may be biased toward one side of the blood vessel, and the bias may change throughout the pullback, causing the blood vessel to have a wavy path on the longitudinal display. Rotating the longitudinal display to see different views of the blood vessel may appear unnatural because rotation happens around the imaging body instead of around the center of the blood vessel. Although medical imaging systems have the potential for providing detailed imagesof the inside of vessels, the displayed image often includes various distortions arising duringmovement of the device through the lumen. For example, distortions can include images ina series appearing to be misaligned, improper display of vessel features due to the imagingdevice not precisely following the contours of the vessel, or distortion arising from thehelical motion of the device as it is moved through the vessel. These distortions result inconsiderable intra- and inter-observer variability that may lead to conflicting or incorrect 2024PF00044 patient diagnosis. SUMMARY OF THE INVENTIONThe invention provides methods and systems for correcting translational distortion ina medical image of a lumen of a biological structure. The system assesses the position ofthe lumen with respect to one or more reference points for a first image and then determinesthe displacement of the first image from the reference point. The displacement of the firstimage is used to assess the displacements of the images immediately preceding andimmediately following the first image. The displacement calculation is then performediteratively for the entire data set and the measured displacements are used to establish acommon reference, e.g., an average displacement. Once the common reference isestablished, each image is then transformed to compensate for the displacement with respectto the common reference, thus allowing a corrected image of the lumen to be created anddisplayed. A system of the invention includes a processor and memory upon which is storedinstructions to carry out the steps above. Some embodiments of the system additionallycomprise an imaging device, e.g., an imaging catheter.The invention is generally applicable to data from any image gathering devices that acquireand process one, two, or three dimensional data sets from which three dimensional imagecompositions are derived. Exemplary devices include tomographic devices such as opticalcoherence tomography (OCT) devices, photo acoustic imaging devices, intravascular spectroscopy, intravascular magnetic resonance imaging, and ultrasound devices, includingintravascular ultrasound (IVUS). The invention is particularly well suited for imaging devicesthat make a large number of measurements while rotating and translating, such as pull-backcatheter imaging devices. Through the use of the image processing techniques described herein, the vascularstructure border for all imaging frames, or any subsets thereof, in a recorded data set arecorrected for image distortions and provided to the user. Corrected lumen border images areprovided to the user in one, two and three dimensional image displays by the methods andsystems provided. The resulting corrected lumen border may be displayed as the finaltomographic image, the image longitudinal display (ILD), splayed image and threedimensional image. User interface graphics provide input for other indicators on a monitor 2024PF00044interface, such as a color bar indicating the size of the lumen.In other aspects, the invention embodies a system for displaying a medical image of avessel. The system may use a monitor to display an image of the lumen of the biologicalstructure, a central processing unit (CPU), and storage coupled to the CPU for storinginstructions. The system may be configured so that the CPU obtains image data of a lumenof a biological structure from an imaging device and corrects the image data for translationaldistortions and displays a corrected image. Alternatively, the image data may be collectedwith a device and stored for later processing and use. In some embodiments, the system isused to correct images of intravascular lumen and the resulting images are displayed in alumen-centric view. The image data to be corrected may include any one of or combinations of splayedimage data, image longitudinal display (ILD) data, three dimensional image data andtomographic image data. Exemplary translational distortions to be corrected include framealignment distortion, device angular distortion, and helical offset distortion. BRIEF DESCRIPTION OF THE DRAWINGSFIG. 1 illustrates a partial cross-sectional view of an imaging catheter suitable for usewith a rotational imaging system; FIG.2 illustrates the geometry of a data stream acquired;FIG. 3 illustrates an example of one source of distortion in OCT image data that isdue to the change in position of a rotational imaging catheter relative to a vessel lumen wallas it is longitudinally displaced within the length of a vessel;FIG. 4 shows a single frame image of a vessel lumen appearing off-center because thecatheter occupies the center of the image; FIG. 5 shows an image longitudinal display (ILD) composed of a series of imageframes where the catheter position varies relative to the lumen border. Each of the 200individual lumen border images shifts out of alignment from other image frame lumenborders through the series, while the catheter remains in alignment; FIG.6 shows an example of a splayed image two-dimensional map of a vessel pullback; FIG. 7 shows a three dimensional surface display of vessel lumen border centered 2024PF00044relative to an imaging catheter. The three-dimensional display is constructed fromuncorrected two- dimensional images; FIG. 8 is a flow chart illustrating an algorithm that may be used by a system of theinvention; FIG. 9A shows an IVUS pullback ILD image with a catheter-centric image;FIG. 9B shows the IVUS pullback ILD image after transformation to a vessel-centricimage using a method of the invention. Variations in the vessel topology are much easier toidentify in FIG. 9B, therefore increasing the likelihood of proper diagnosis;FIG. 10 shows another embodiment of an IVUS pullback ILD image with a cathetercentric image; FIG. 11 shows another embodiment of the IVUS pullback ILD image aftertransformation to a vessel-centric image using a method of the invention. Variations in thevessel topology are much easier to identify in FIG. 11, therefore increasing the likelihood ofproper diagnosis; FIG. 12 is a block diagram of a system for correcting translational distortion in amedical image of a lumen; FIG. 13 is a block diagram of a system for correcting translational distortion in amedical image of a lumen; FIG. 14 is a block diagram of a system for correcting translational distortion in amedical image of a lumen. DETAILED DESCRIPTIONThe invention provides methods and systems for correcting translational distortion in amedical image of a lumen of a biological structure. The method facilitates vessel visualizationin intravascular images (e.g. IVUS, OCT) used to evaluate the cardiovascular health of apatient. Using the methods and systems described herein it is simpler for a provider to evaluatevascular imaging data, which is typically distorted due to cardiac vessel-catheter motionwhile the image was acquired. The invention applies a motion correction algorithm to theimages prior to generating vessel-centric images as an alternative to traditional catheter- 2024PF00044centric display views.Medical imaging is a general technology class in which sectional andmultidimensional anatomic images are constructed from acquired data. The data can becollected from a variety of acquisition systems including, but not limited to, magneticresonance imaging (MRI), radiography methods including fluoroscopy, x-ray tomography,computed axial tomography and computed tomography, optical coherence tomography(OCT), nuclear medicine techniques such as scintigraphy, positron emission tomographyand single photon emission computed tomography, photo acoustic imaging ultrasounddevices and methods including, but not limited to, intravascular ultrasound spectroscopy(IVUS), ultrasound modulated optical tomography, ultrasound transmission tomography,other tomographic techniques such as electrical capacitance, magnetic induction, functionalMRI, optical projection and thermo-acoustic imaging, combinations thereof andcombinations with other medical techniques that produce two- and three-dimensionalimages. At least all of these techniques are contemplated for use with the systems andmethods of the present invention. Medical imaging systems well suited for the present invention include , but notlimited to, optical coherence tomography (OCT), intravascular ultrasound (IVUS), RAMANspectroscopy, alternative interferometric techniques, therapeutic or diagnostic deliverydevices, pressure wires, and the like. Medical imaging system images (e.g. OCT and IVUSimages) are acquired in the polar domain with coordinates of radius and angle (r, theta) butneed to be converted to Cartesian coordinates (x, y) for display or rendering on a computermonitor. Typically, medical imaging systems consist of an imaging core which pulls back(or pushes forward) while recording an image video loop. This motion results in a threedimensional dataset of two dimensional image frames, where each frame provides a 360°slice of the vessel at different longitudinal locations.In some embodiments, the system can be used to correct images obtained withintravascular ultrasound imaging (IVUS). Accordingly, the imaging assembly can be aphased array IVUS imaging assembly, a pull-back type IVUS imaging assembly, or anIVUS imaging assembly that uses photoacoustic materials to produce diagnostic ultrasoundand / or receive reflected ultrasound for diagnostics. IVUS imaging assemblies andprocessing of IVUS data are described for example in Yock, U.S. Pat. Nos. 4,794,931, 2024PF000445,000,185, and 5,313,949; Sieben et al., U.S. Pat. Nos. 5,243,988, and 5,353,798; Crowleyet al., U.S. Pat. No. 4,951,677; Pomeranz, U.S. Pat. No. 5,095,911, Griffith et al., U.S. Pat.No. 4,841,977, Maroney et al., U.S. Pat. No. 5,373,849, Born et al., U.S. Pat. No.5,176,141, Lancee et al., U.S. Pat. No. 5,240,003, Lancee et al., U.S. Pat. No. 5,375,602,Gardineer et at., U.S. Pat. No.5,373,845, Seward et al., Mayo Clinic Proceedings71(7):629-635 (1996), Packer et al., Cardiostim Conference 833 (1994), "UltrasoundCardioscopy," Eur. J.C.P.E. 4(2):193 (June 1994), Eberle et al., U.S. Pat.No. 5,453,575, Eberle et al., U.S. Pat. No. 5,368,037, Eberle et at., U.S. Pat. No. 5,183,048,Eberle et al., U.S. Pat. No.5,167,233, Eberle et at., U.S. Pat. No.4,917,097, Eberle et at.,U.S. Pat. No.5,135,486, and other references well known in the art relating to intraluminalultrasound devices and modalities. All of these references are incorporated by referenceherein. Another medical imaging technique contemplated herein is optical coherencetomography (OCT). OCT systems and methods are generally described in Milner et al., U.S.Patent Application Publication No. 2011 / 0152771, Condit et al., U.S. Patent ApplicationPublication No. 2010 / 0220334, Castella et al., U.S. Patent Application Publication No.2009 / 0043191, Milner et al., U.S. Patent Application Publication No.2008 / 0291463, andKemp, N., U.S. Patent Application Publication No. 2008 / 0180683, the content of each ofwhich is incorporated by reference in its entirety. OCT is a medical imaging methodologyusing a specially designed catheter with a miniaturized near infrared light-emitting probeattached to the distal end of the catheter. As an optical signal acquisition and processingmethod, it captures micrometer-resolution, three-dimensional images from within opticalscattering media (e.g., biological tissue). OCT allows the application of interferometrictechnology to see from inside, for example, blood vessels, visualizing the endothelium(inner wall) of blood vessels in living individuals. OCT systems may be a spectrometerbased OCT system or a Fourier Domain OCT, as disclosed in U.S. Patent Application No.2009 / 0046295, herein incorporated by reference.Various lumen of biological structures may be imaged with aforementioned imagingtechnologies in addition to blood vessels, including, but not limited, to vasculature of thelymphatic and nervous systems, various structures of the gastrointestinal tract includinglumen of the small intestine, large intestine, stomach, esophagus, colon, pancreatic duct, bile 2024PF00044duct, hepatic duct, lumen of the reproductive tract including the vas deferens, vagina, uterusand fallopian tubes, structures of the urinary tract including urinary collecting ducts, renaltubules, ureter, and bladder, and structures of the head and neck and pulmonary systemincluding sinuses, parotid, trachea, bronchi, and lungs. The arteries of the heart are particularly useful to examine with imaging devices.Imaging of the coronary arteries can determine the amount of plaque built up at anyparticular point in the coronary artery. The accumulation of plaque within the artery wallover decades is the setup for vulnerable plaque which, in tum, leads to heart attack andstenosis (narrowing) of the artery. IVUS and OCT are useful in determining both plaquevolume within the wall of the artery, and the degree of stenosis of the artery lumen. It can beespecially useful in situations in which angiographic imaging is considered unreliable, suchas for the lumen of ostial lesions or where angiographic images do not visualize lumensegments adequately. Example regions include those with multiple overlapping arterialsegments. It is also used to assess the effects of treatments of stenosis such as with hydraulicangioplasty expansion of the artery, with or without stents, and the results of medicaltherapy over time. FIG. 1 illustrates an exemplary catheter 100 for imaging inside a lumen of anyanatomical or mechanical conduit, vessel, or tube. The exemplary catheter 100 is suitablefor in vivo imaging, particularly for imaging of an anatomical lumen or passageway, such asa cardiovascular, neurovascular, gastrointestinal, genitor-urinary tract, or other anatomicalluminal structure. For example, FIG. 1 illustrates a vascular lumen 102 within a vessel 104including a plaque buildup 106. The exemplary catheter 100 may include a rapid accesslumen 108 suitable for guiding the catheter 100 over a guide-wire 110.The exemplary catheter 100 is disposed over an exemplary rotational imagingmodality 112 that rotates about a longitudinal axis 114 thereof as indicated by arrow 116.The exemplary rotational imaging modality 112 may comprise, in one embodiment, an OCTsystem. OCT is an optical interferometric technique for imaging subsurface tissue structurewith micrometer-scale resolution. In another embodiment, the exemplary rotational imagingmodality 112 may comprise an ultrasound imaging modality, such as an IVUS system,either alone or in combination with an OCT imaging system. An exemplary OCT systemmay include a tunable laser or broadband light source or multiple tunable laser sources with 2024PF00044corresponding detectors, and may be a spectrometer based OCT system or a Fourier DomainOCT system, as disclosed in U.S. Patent Application Publication No.2009 / 0046295, hereinincorporated by reference. The exemplary catheter 100 may be integrated with IVUS by anOCT-IVUS system for concurrent imaging, as described in, for example, Castella et al. U.S.Patent Application Publication No. 2009 / 0043191 and Dick et al. U.S. Patent ApplicationPublication No. 2009 / 0018393, both incorporated by reference in their entirety herein.Referring to FIGS. 1 and 2, the rotational imaging modality 112 may belongitudinally translated during rotation, as indicated by line 118 in FIG. 1. Thus, therotational imaging modality 112 acquires data along a path 120 that includes a combinationof rotation and / or longitudinal translation of the rotational imaging modality 112.Referring to FIG. 1, the longitudinal axis 114 is illustrated as linear for simplicityand clarity. However, the longitudinal axis 114 is not necessarily linear as illustrated. Thelongitudinal axis 114 may be curvilinear having a curvature following a tortuosity of thevessel 104. It will be understood that vessel 104 need not be linear, but may in fact have acurvilinear longitudinal axis 104 following the vessel 104 along a tortuous geometry, andthat the present invention equally applicable to an imaging modality 112 longitudinallytranslated along the vessel 104 having a longitudinally linear and / or tortuous geometry.Referring to FIG. 2, a portion of the three dimensional space within and beneath theluminal surface 122 scanned within a single rotational period is projected into a planar (two-dimensional) format. In this format, line 126 represents a circumferential axis plottedhorizontally. The geometry of a data stream acquired utilizing the above-described helicalscan pattern 120 relative to the geometry of the luminal surface 122 may be represented bythe parallelogram 124 disposed over the horizontal line 126 in FIG. 2. Starting at a fixeddata acquisition angle 200 (hereinafter a "FDAA 200") conveniently denoted as zerodegrees (0°) in FIG. 2, the rotational imaging modality 112 acquires data following arotational path indicated by line 128 (parallel to the line 126) in FIG. 2. However, becausethe rotational imaging modality 112 may also be translated longitudinally, as indicated byline 130 in FIG. 2, the two- dimensional representation of the scanned three-dimensionalspace within and beneath the luminal surface 122 comprises the shape of the parallelogram124. This means that at the end of one full rotation of the rotational imaging modality 112 asdenoted in FIG. 2 by the FDAA 200 having a value of 360 °, the rotational imaging 2024PF00044modality 112 has translated longitudinally by a distance Z.To perform the analysis of a clinical condition, images acquired with the rotationalimaging devices are reconstructed in various display formats. However, the displayedimages often have artifacts generated during the acquisition or processing of the acquireddata. Artifacts arise from, for example, shadows in the lumen border from stents and guidewires used in the catheter portion of the imaging device. Other artifacts arise from any of avariety of dynamic motional effects including, for example, cardiac motion of the patient orexternal movement of the catheter. Because all scans are relative to the catheter imaging core, the catheter istraditionally represented at the center of a tomographic image. Accordingly, other artifactsinclude lumen image distortions and frame to frame offset or misalignment of the lumen dueto the catheter not being centrally located during translational motion. Such distortion istypically ascribed to the inherent tortuosity of the biological structure being imaged. Stillother distortions arise from a discontinuity of the imaging data for a two-dimensional imageslice as a result of the helical offset of the scan imaged. Such an offset arises from thecombined rotational and translational motions of the imaging device, in which during a full360° rotational scan the imaging core has translated longitudinally be a distance Z.Several image distortions commonly obtained from rotational imaging devices aredescribed in FIGS. 4-8. Catheters generally have low ductility relative to a lumen and cannotconform exactly to the tortuous shape of, for example, a blood vessel in which it is imaging.FIG. 3 illustrates an example of one source of distortion in OCT image data that is due to thechange in position of a rotational imaging catheter relative to a vessel lumen wall as it islongitudinally displaced within the length of a vessel. Because all images are relative to thecatheter imaging core, the catheter always appears in the center of the image and successiveimages appear as though the vessel is shifting position around the catheter imaging core.This effect will cause the vessel at times to appear off-centered in the tomographic, splayed,two and three-dimensional images and Image Longitudinal Displays (ILD). FIG. 4 shows asingle frame image of a vessel lumen appearing off-center because the catheter occupies thecenter of the image. FIG. 5 shows an ILD composed of a series of image frames where thecatheter position varies relative to the lumen border. Each of the 200 individual lumen borderimages shifts out of alignment from other image frame lumen borders through the series, 2024PF00044while the catheter remains in alignment. Thus, in either the tomographic or ILD imageframes obtained during catheter pullback, the vessel may appear to move around thecatheter. Another example of an image display type that often has a distorted presentation is a"splayed image." FIG.6 shows an example of a splayed image two-dimensional map of avessel pullback. The x-axis is rotational angle of the lumen border relative to the imagingdevice, and the y-axis is frame number. A splayed image is generated by integrating allpixel intensities beyond the vessel lumen border across all A-scans for all frames. Since asplayed image is constructed by integrating along A-scans, the coordinates of the resultingsignal are presented relative to the catheter center, where the x-axis corresponds to the anglerelative to the center of the image. The stent struts, due to their shadowing effect, are clearlyseen in the image data. However, the angular spacing of the stent struts varies as caused bythe eccentricity of the catheter during the pullback. The systems and methods describedherein can be used to correct distortions and create a more accurate depiction of the stentdistribution. Athree dimensional model of vessel wall is usually constructed through theacquisition of a series of two dimensional images, and therefore also may display distortionsbased on those present in the two-dimensional images. FIG. 7 shows a three-dimensionalsurface reconstruction of a vessel wall with distortional artifacts because it is constructedfrom uncorrected two- dimensional images. As in FIGS. 4-7, the position of the vessel wallis determined relative positioned to the catheter, and therefore the surface of the three-dimensional model is slightly distorted by the change in position of the catheter along thepullback. To counteract these distortions, systems of the invention determine commonreference points in the acquired data and then transform the data to produce a vessel-centricimage that is easier to analyze and diagnose. In particular the invention uses a methodwhich (a) determines the vessel center in each frame, then (b) finds the true center of the vesselthrough the borders of each IVUS frame, (c) corrects the ILD by translating each IVUS frame sothat the center of each vessel for all frames is all at the same location, and finally (d) applies thetranslated images and reconstructs the ILD producing a display through the vessel center instead of the catheter center. 2024PF00044 The primary advantage is the ability to create vessel-centric display viewsconsistently stabilizing vessel position and orientation along a pullback. The known methodssuffer from their inability to achieve vessel alignment for more than a few image frames,inability to compensate for significant vessel shift, and / or inability to hold the catheterwithin a longitudinal field of view.The resultant vessel-centric views provide users with a clearer and more consistentvisual appearance of the vessel anatomy than traditional catheter-centric views. Moreover,the vessel- centric image availability facilitates further automated analysis of the anatomy,for example, segmentation of lumen and adventitia, plaque characterization, and likewise.The method can be used in any intravascular procedures involving an imaging catheter in acoronary artery where physiologic cardiac motion occurs. It can be used in diagnostic and / orimage-guided therapy purposes. It can be applied to different imaging modalities such asIVUS, OCT, intravascular spectroscopy, photo-acoustic tomography and similar. Themethod is not restricted to planar scanning in an imaging plane orthogonal to the vessel axis,and it is also applicable with conical scanning geometry such as used in forward-lookingIVUS imaging. As described in FIG. 8, the method principally involves evaluating each image dataset for vessel markers, and compiling the positions of the vessel markers to establish atransform function that is used to individually reverse transform each frame so that thecorrected frames can be assembled into one or more images, e.g., tomographic views.While there is a potential for accumulation of stray errors for long frame sequences,such errors can be addressed by filtering the sequence of accumulated transformations. Forexample, a temporal filter may be applied to compensate for a DC offset and to smooth outany jitter caused by errors in detection of elementary transformations between neighboringframe pairs. In another instance the filtering step can employ two separate bandpass filters,one for the rotational and one for the translational components of the accumulated rigidtransformation. Each of those filters can, for example, consist of a weighted average of thethree most recent accumulated values to smooth out any jitter that is followed by asubtraction of a "longer term" averaged over sixty recent frames value to compensate for aDC offset. Once the filtered accumulated transformation for an image frame is obtained,motion compensation is computed to spatially align the vessel across the frame sequence. 2024PF00044 The computed compensation aims to present the vessel anatomy in the images as if there were no cardiac motion. Once the transformation function has been identified, eachtomographic frame is reverse transformed to normalize the entire image set. Based on aframe sequence and the corresponding sequence of compensation transformations, a seriesof stabilized tomographic frames can be produced, where the vessel appears stationary andthe catheter appears to float within the vessel. As a result of compensating for the DC offset,the catheter floating is bounded by short-term cardiac motion within the few nearest cardiaccycles in the pullback and any drastic drift out of the field of view is prevented.The application of the algorithm of the invention to an IVUS vascular image isshown in FIGS. 9A and 9B. The ILD view represents a longitudinal cross-section through asequence of frames created by selecting two diametrically opposed scan lines from eachframe and stacking them into an image. In FIG. 9A, the sequence of frames is assembledusing the imaging axis as a reference point, which is standard method in many imagingsystems. However, in FIG. 9B, the scan lines are assembled as a series of motioncompensated frames. The filtered accumulated rigid transformation is decomposed into itsrotational and translational components, and the rotational component is subtracted from theILD view cross-sectional angle to determine the motion compensated diameter. Next, theselected scan lines are shifted radially within the ILD and the applied radial shift equals tothe projection of the negative of the translational component discussed above. This radialshift allows the catheter center to float within the ILD view according to the detectedmotion. At the same time any transversal motion of the catheter center gets absorbed by theILD view so that the entire motion compensated diameter remains visible, similarly to acurved multi-planar reconstruction commonly used in radiography.Another embodiment is shown in Fig. 10. A longitudinal display is created where each lineis centered around the imaging modality 112, rather than centered around the centroid 105 of thevessel 104 or, alternatively, centroid 103 of the lumen 102. “Peaks” 107 in the longitudinal displaydue to cardiac motion change the orientation and the position of the imaging modality 112 relative to the vessel 104. A wave like path of the lumen 102 and the vessel 104 on the longitudinal display is due to the imaging modality 112 being on different sides of the vessel 104 during different parts of the pullback. Field of views are shown corresponding with locations on the longitudinal display. Fig. 11 shows the desired view of the longitudinal display. The center 105 of the vessel 104 2024PF00044for each frame needs to be found by vessel border detection like U.S. Pat. No. 11,744,527 Scott etal., and U.S. Pat. No. 11,272,845, Cheline et al. for example. Then the corrected longitudinaldisplay is generated by “slicing” each frame through this point at any angle, instead of through theimaging modality 112 and rotating the direction of the “slice” to center around the center 105 of thevessel 104. Doing so straightens the path of the longitudinal display, making it easier to interpretwhere each line of the longitudinal display is centered around the center 105 of the vessel 104rather than around the center of the imaging modality 112. In some embodiments, the composed ILD view is further placed into a viewport, forexample cropped to a rectangular window and rendered in a display. Based on a framesequence and a respective sequence of compensation transformations, any number of ILDviews corresponding to a number of cross-sections with different view angles can begenerated in parallel in order to let users interactively control the view angle being rendered.A system of the invention may be implemented in a number of formats. Anembodiment of a system 300 of the invention is shown in FIG. 12. The core of the system300 is a computer 360 or other computational arrangement comprising a processor 365 andmemory 367. The memory has instructions which when executed cause the processor todetermine a baseline measurement prior to conducting a therapeutic procedure anddetermine a post-therapy measurement after conducting the therapeutic procedure. Theinstructions may also cause the computer to compare the post-therapy measurement to thebaseline measurement, thereby determining the degree of post-therapy improvement afterconducting the therapeutic procedure. The physiological measurement data of vasculaturewill typically originate from an intravascular measurement device 320, which is in electronicand / or mechanical communication with a sensing catheter 325. Having collected thebaseline measurement and post-therapy measurement, the processor then processes andoutputs the results. The results are typically output to a display 380 to be viewed by aphysician or technician. In advanced embodiments, system 300 may comprise an imaging engine 370 whichhas advanced image processing features, such as image tagging, that allow the system 300to more efficiently process and display intravascular and angiographic images. The imagingengine 370 may automatically highlight or otherwise denote areas of interest in thevasculature. The imaging engine 370 may also produce 3D renderings or other visual 2024PF00044representations of the physiological measurements. In some embodiments, the imagingengine 370 may additionally include data acquisition functionalities (DAQ) 375, whichallow the imaging engine 370 to receive the physiological measurement data directly fromthe catheter 325 or collector 347 to be processed into images for display.Other advanced embodiments use the 1 / 0 functionalities 362 of computer 360 tocontrol the intravascular measurement 320. In these embodiments, computer 360 may causethe imaging assembly of catheter 325 to travel to a specific location, e.g., if the catheter 325is a pull-back type. While not shown here, it is also possible that computer 360 may controla manipulator, e.g., a robotic manipulator, connected to catheter 325 to improve theplacement of the catheter 325.A system 400 of the invention may also be implemented across a number of independentplatforms which communicate via a network 409, as shown in FIG. 13. Methods of theinvention can be performed using software, hardware, firmware, hardwiring, orcombinations of any of these. Features implementing functions can also be physicallylocated at various positions, including being distributed such that portions of functions areimplemented at different physical locations (e.g., imaging apparatus in one room and hostworkstation in another, or in separate buildings, for example, with wireless or wiredconnections). As shown in FIG. 13, the intravascular detecting system 320 facilitate obtaining thedata, however the actual implementation of the steps can be performed by multipleprocessors working in communication via the network 409, for example a local areanetwork, a wireless network, or the internet. The components of system 400 may also bephysically separated. For example, terminal 467 and display 380 may not be geographicallylocated with the intravascular detection system 320.As shown in FIG. 13, imaging engine 859 communicates with host workstation 433as well as optionally server over network 409. In some embodiments, an operator uses hostworkstation 433, computer 360, or terminal 467 to control system 400 or to receive images.An image may be displayed using an I / O 362,437, or 471, which may include a monitor.Any I / O may include a monitor, keyboard, mouse, or touch screen to communicate with anyof processor 365, 441, or 475, for example, to cause data to be stored in any tangible,nontransitory memory 445,479, or 367. Input from a user is received by a processor in an 2024PF00044electronic device such as, for example, host workstation 433, or computer 449. In certainembodiments, host workstation 433 and imaging engine 859 are included in a bedsideconsole unit to operate system 400. In some embodiments, a user interacts with a visual interface and puts in parametersor makes a selection. Input from a user (e.g., parameters or a selection) are received by aprocessor in an electronic device such as, for example, host workstation 433, or computer360. The selection can be rendered into a visible display. In some embodiments, an operatoruses host workstation 433, computer 449, or terminal 467 to control system 400 or toreceive images. An image may be displayed using an I / O 362,437, or 471, which mayinclude a monitor. Any I / O may include a keyboard, mouse or touch screen to communicatewith any of processor 365, 441, or 475, for example, to cause data to be stored in anytangible, nontransitory memory 445, 479, or 367. Methods of the invention can beperformed using software, hardware, firmware, hardwiring, or combinations of any of these.Features implementing functions can also be physically located at various positions,including being distributed such that portions of functions are implemented at differentphysical locations (e.g., imaging apparatus in one room and host workstation in another, orin separate buildings, for example, with wireless or wired connections). In certainembodiments, host workstation 433 and imaging engine 859 are included in a bedsideconsole unit to operate system 400. Processors suitable for the execution of computer program include, by way ofexample, both general and special purpose microprocessors, and any one or more processorof any kind of digital computer. Generally, a processor will receive instructions and datafrom a read-only memory or a random access memory or both. The essential elements ofcomputer are a processor for executing instructions and one or more memory devices forstoring instructions and data. Generally, a computer will also include, or be operativelycoupled to receive data from or transfer data to, or both, one or more mass storage devicesfor storing data, e.g., magnetic, magneto-optical disks, or optical disks. Information carrierssuitable for embodying computer program instructions and data include all forms of non-volatile memory, including by way of example semiconductor memory devices, (e.g.,EPROM, EEPROM, NAND-based flash memory, solid state drive (SSD), and other flashmemory devices); magnetic disks, (e.g., internal hard disks or removable disks); magneto- 2024PF00044optical disks; and optical disks (e.g., CD and DVD disks). The processor and the memorycan be supplemented by, or incorporated in, special purpose logic circuitry.To provide for interaction with a user, the subject matter described herein can beimplemented on a computer having an 1 / 0 device, e.g., a CRT, LCD, LED, or projectiondevice for displaying information to the user and an input or output device such as akeyboard and a pointing device, (e.g., a mouse or a trackball), by which the user can provideinput to the computer. Other kinds of devices can be used to provide for interaction with auser as well. For example, feedback provided to the user can be any form of sensoryfeedback, (e.g., visual feedback, auditory feedback, or tactile feedback), and input from theuser can be received in any form, including acoustic, speech, or tactile input.The subject matter described herein can be implemented in a computing system thatincludes a back-end component (e.g., a data server 413), a middleware component (e.g., anapplication server), or a front-end component (e.g., a client computer 449 having a graphicaluser interface 454 or a web browser through which a user can interact with animplementation of the subject matter described herein), or any combination of such back-end, middleware, and front- end components. The components of the system can beinterconnected through network 409 by any form or medium of digital data communication,e.g., a communication network. Examples of communication networks include cellnetworks (3G, 4G), a local area network (LAN), and a wide area network (WAN), e.g., theInternet. The subject matter described herein can be implemented as one or more computerprogram products, such as one or more computer programs tangibly embodied in aninformation carrier (e.g., in a non-transitory computer-readable medium) for execution by, orto control the operation of, data processing apparatus (e.g., a programmable processor, acomputer, or multiple computers). A computer program (also known as a program, software,software application, app, macro, or code) can be written in any form of programminglanguage, including compiled or interpreted languages (e.g., C, C++, Perl), and it can bedeployed in any form, including as a stand-alone program or as a module, component,subroutine, or other unit suitable for use in a computing environment. Systems and methodsof the invention can include programming language known in the art, including, withoutlimitation, C, C++, Perl, Java, ActiveX, HTML5, Visual Basic, or JavaScript. 2024PF00044 Acomputer program does not necessarily correspond to a file. A program can bestored in a portion of file 417 that holds other programs or data, in a single file dedicated tothe program in question, or in multiple coordinated files (e.g., files that store one or moremodules, sub-programs, or portions of code). A computer program can be deployed to beexecuted on one computer or on multiple computers at one site or distributed across multiplesites and interconnected by a communication network.A file can be a digital file, for example, stored on a hard drive, SSD, CD, or othertangible, non-transitory medium. A file can be sent from one device to another over network409 (e.g., as packets being sent from a server to a client, for example, through a NetworkInterface Card, modem, wireless card, or similar). Writing a file according to the invention involves transforming a tangible, non-transitory computer-readable medium, for example, by adding, removing, or rearrangingparticles (e.g., with a net charge or dipole moment) into patterns of magnetization byread / write heads, the patterns then representing new collocations of information desired by,and useful to, the user. In some embodiments, writing involves a physical transformation ofmaterial in tangible, non- transitory computer readable media with certain properties so thatoptical read / write devices can then read the new and useful collocation of information. Insome embodiments, writing a file includes using flash memory such as NAND flashmemory and storing information in an array of memory cells include floating-gatetransistors. Methods of writing a file are well-known in the art and, for example, can beinvoked automatically by a program or by a save command from software or a writecommand from a programming language.In certain embodiments, display 380 is rendered within a computer operating systemenvironment, such as Windows, Mac OS, or Linux or within a display or GUI of aspecialized system. Display 380 can include any standard controls associated with a display(e.g., within a windowing environment) including minimize and close buttons, scroll bars,menus, and window resizing controls. Elements of display 380 can be provided by anoperating system, windows environment, application programming interface (API), webbrowser, program, or combination thereof (for example, in some embodiments a computerincludes an operating system in which an independent program such as a web browser runsand the independent program supplies one or more of an API to render elements of a GUI). 2024PF00044Display 380 can further include any controls or information related to viewing images (e.g.,zoom, color controls, brightness / contrast) or handling files comprising three-dimensionalimage data (e.g., open, save, close, select, cut, delete, etc.). Further, display 380 can includecontrols (e.g., buttons, sliders, tabs, switches) related to operating a three dimensional imagecapture system (e.g., go, stop, pause, power up, power down).In certain embodiments, display 380 includes controls related to three dimensionalimaging systems that are operable with different imaging modalities. For example, display380 may include start, stop, zoom, save, etc., buttons, and be rendered by a computerprogram that interoperates with IVUS, OCT, or angiogram modalities. Thus display 380 candisplay an image derived from a three-dimensional data set with or without regard to theimaging mode of the system.Alternatively, an imaging data set may be assessed, analyzed, and transformed witha system such as the system shown in FIG. 14, comprising CPU 1510, storage 1520, andmonitor 1530. Storage 1520 may contain instructions for carrying out methods of theinvention, e.g., to configure CPU 1510 to analyze the imaging data set for a parameter,assign an indicator to the medical device based on the presence of the parameter, anddisplay the indicator on monitor 1530. For example CPU 1510 may direct monitor 1530 todisplay a longitudinal image of a lumen with a color-coded stent. In some embodiments, asystem of the invention will additionally comprise graphical user interface (GUI) 1540,which allows a user to interact with the images. In some embodiments, CPU 1510, storage1520, and monitor 1530 may be encompassed within system 2400. The systems and methods of use described herein can be performed using any typeof computing device, such as a computer, that includes a processor or any combination ofcomputing devices where each device performs at least part of the process or method. Insome embodiments, systems and methods described herein may be performed with ahandheld device, e.g., a smart tablet, or a smart phone, or a specialty device produced forthe system. In some embodiments, a device of the invention includes an OCT imaging systemand obtains a three-dimensional data set through the operation of OCT imaging hardware. Insome embodiments, a device of the invention is a computer device such as a laptop, desktop,or tablet computer, and obtains a three-dimensional data set by retrieving it from a tangible 2024PF00044storage medium, such as a disk drive on a server using a network or as an email attachment.Methods of the invention can be performed using software, hardware, firmware,hardwiring, or combinations of any of these. Features implementing functions can also bephysically located at various positions, including being distributed such that portions offunctions are implemented at different physical locations (e.g., imaging apparatus in one roomand host workstation in another, or in separate buildings, for example, with wireless or wiredconnections). Any target can be imaged by methods and systems of the invention including, forexample, bodily tissue. In certain embodiments, systems and methods of the inventionimage within a lumen of tissue. Various lumen of biological structures may be imagedincluding, but not limited to, blood vessels, vasculature of the lymphatic and nervoussystems, various structures of the gastrointestinal tract including lumen of the smallintestine, large intestine, stomach, esophagus, colon, pancreatic duct, bile duct, hepatic duct,lumen of the reproductive tract including the vas deferens, vagina, uterus and fallopiantubes, structures of the urinary tract including urinary collecting ducts, renal tubules, ureter,and bladder, and structures of the head and neck and pulmonary system including sinuses,parotid, trachea, bronchi, and lungs. Incorporation by ReferenceReferences and citations to other documents, such as patents, patent applications, patentpublications, journals, books, papers, web contents, have been made throughout thisdisclosure. All such documents are hereby incorporated herein by reference in their entiretyfor all purposes.Equivalents The invention may be embodied in other specific forms without departing from thespirit or essential characteristics thereof. The foregoing embodiments are therefore to beconsidered in all respects illustrative rather than limiting on the invention described herein.Scope of the invention is thus indicated by the appended claims rather than by the foregoingdescription, and all changes which come within the meaning and range of equivalency of theclaims are therefore intended to be embraced therein.

Claims

2024PF00044 CLAIMS 1. A system, comprising a processor circuit configured for communication with an intravascular imaging catheter, wherein the processor circuit is configured to: control the intravascular imaging catheter to obtain a plurality of intravascular images along a blood vessel, wherein each intravascular image comprises a radial cross-sectional view of the blood vessel; identify at least one of a vessel border or a lumen border within the plurality of intravascular images; determine, based on at least one of the vessel border or the lumen border, a center of the blood vessel within the plurality of intravascular images; generate a longitudinal view of the blood vessel using the plurality of intravascular images, wherein the center of the blood vessel within the plurality of intravascular images is aligned in the longitudinal view; and output the longitudinal view to a display in communication with the processor.

2. The system of claim 1, wherein the plurality of intravascular images are obtained during movement of the intravascular imaging catheter through the blood vessel.

3. The system of claim 1, wherein the longitudinal view is successively generated while the plurality of intravascular are obtained.

4. The system of claim 1, wherein the longitudinal view directly comprises image content from the plurality of intravascular images.

5. The system of claim 1, wherein the longitudinal view is not a stylized representation generated using a dimension of at least one of the vessel border or the lumen border.

6. The system of claim 1, wherein a shape of the vessel such that the lumen contour or the vessel contour is not attributable to a location of the intravascular imaging catheter within in the blood vessel.

7. The system of claim 1, wherein at least one of shape of a lumen contour or a vessel contour in the longitudinal view is representative of the shape of the blood vessel.

8. The system of claim 1, wherein the plurality of intravascular images is acquired withoptical coherence tomography (OCT).

9. The system of claim 1, wherein the plurality of intravascular images is acquired withintravenous ultrasound imaging (IVUS).2024PF00044 10. A method, comprising: obtaining a plurality of intravascular images along a blood vessel from an intravascularcatheter, wherein each intravascular image comprises a radial cross-sectional view of the blood vessel; identifying at least one of a vessel border or a lumen border within the plurality ofintravascular images; determining, based on at least one of the vessel border or the lumen border, a center of the blood vessel within the plurality of intravascular images; generating a longitudinal view of the blood vessel using the plurality of intravascularimages, wherein the center of the blood vessel within the plurality of intravascular images is aligned in the longitudinal view; and outputting the longitudinal view to a display.

11. The method of claim 10, wherein the plurality of intravascular images are obtainedduring movement of the intravascular imaging catheter through the blood vessel.

12. The method of claim 10, wherein the longitudinal view is successively generated whilethe plurality of intravascular are obtained.

13. The method of claim 10, wherein the longitudinal view directly comprises imagecontent from the plurality of intravascular images.

14. The method of claim 10, wherein the longitudinal view is not a stylized representationgenerated using a dimension of at least one of the vessel border or the lumen border.

15. The method of claim 10, wherein a shape of the vessel such that the lumen contour orthe vessel contour is not attributable to a location of the intravascular imaging catheter within in the blood vessel.

16. The method of claim 10, wherein at least one of shape of a lumen contour or a vesselcontour in the longitudinal view is representative of the shape of the blood vessel.

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