Abstract: Flow reduction hood systems are described which facilitate the visualization of tissue regions through a clear fluid. Such a system may include an imaging hood having one or more layers covering the distal opening and defines one or more apertures which control the infusion and controlled retention of the clearing fluid into the hood. In this manner, the amount of clearing fluid may be limited and the clarity of the imaging of the underlying tissue through the fluid within the hood may be maintained for relatively longer periods of time by inhibiting, delaying, or preventing the infusion of surrounding blood into the viewing field. The aperture size may be controlled to decrease or increase through selective inflation of the membrane or other mechanisms.

Abstract: This invention relates to method and apparatus for collection of the complete fluorescence emission spectrum and the transient decay of a selected spectral band simultaneously with data acquisition times of less that one second. This invention is useful for studying human tissues and cells in vivo.

Abstract: Biological thick tissue such as skeletal and cardiac muscle is imaged by inserting a probe into the tissue and scanning the tissue at a sufficiently fast rate to mitigate motion artifacts due to physiological motion. According to one example embodiment, such a probe is part of a system that is capable of reverse-direction high-resolution imaging without staining or otherwise introducing a foreign element used to generate or otherwise increase the sensed light. The probe includes a light generator for generating light pulses that are directed towards structures located within the thick tissue. The light pulses interact with intrinsic characteristics of the structures to generate a signal such as SHG or intrinsic fluorescence. Reliance on intrinsic characteristics of the structures is particularly useful for applications in which the introduction of foreign substances to the thick tissue is undesirable.

Abstract: Systems and methods for imaging the reflectance of a substrate, such as a tissue substrate, may include a light source, a light transport body configured to project light from the light source to an examination substrate and transmit light reflected by the examination substrate, and an analysis section in optical communication with the light transport body and having a reflectance avoidance imaging module and at least one of a reflectance spectrophotometry module and a fluorescence imaging module. Methods may include utilizing the microcirculatory flow information, oxygen availability information, and the adequacy of oxygenation of tissue cells information, making an early and sensitive determination regarding states of shock in patients.

Abstract: A fiber-delivered probe suitable for CARS imaging of thick tissues is practical. The disclosed design is based on two advances. First, a major problem in CARS probe design is the presence of a very strong anti-Stokes component in silica delivery fibers generated through a FWM process. Without proper spectral filtering, this component affects the CARS image from the tissue sample. The illustrated embodiments of the invention efficiently suppress this spurious anti-Stokes component through the use of a separate fiber for excitation delivery and for signal detection, which allows the incorporation of dichroic optics for anti-Stokes rejection. Second, the detection of backscattered CARS radiation from the sample is optimized by using a large core multi mode fiber in the detection channel. This scheme produces high quality CARS images free of detector aperture effects. Miniaturization of this fiber-delivered probe results in a practical handheld probe for clinical CARS imaging.

Abstract: An optical sensor that provides lateral viewing while maintaining light polarization is disclosed according to one embodiment of the invention. The sensor includes a sensor body, at least one waveguide and at least one refractive optical element. The sensor body may includes proximal end and a distal end. The waveguide includes a proximal end coincident near the proximal end of the sensor body and a distal end coincident at a point near the distal end of the sensor body. The waveguide may include one or more fiber optic. The waveguide may be positioned within the sensor body. The refractive optical element may be positioned within the sensor near the distal end of the waveguide and may be configured to refract light received from the distal end of the waveguide outward from the sensor. The refractive optical element may include one or more prisms.

Abstract: The invention relates to methods and devices for characterizing tissue in vivo, e.g., in walls of blood vessels, to determine whether the tissue is healthy or diseased, and include methods of displaying results with or without thresholds.

Abstract: Tissue visualization device and method variations are described herein where an imaging hood is temporarily sealed against a region of tissue to be treated while under direct visualization. Such a system may include a deployment catheter and an attached imaging hood deployable into an expanded configuration. The imaging hood is placed against or adjacent to the tissue to be imaged in a body lumen that is normally filled with an opaque bodily fluid such as blood. A translucent or transparent fluid is pumped into the hood until the fluid displaces any blood leaving a clear region of tissue to be imaged via an imaging element. Temporary sealing against the tissue can be achieved in a number of ways such as circumferential balloons inflatable within the hood or other sealing techniques. A field of view of the imaging element can be expanded by inflating the balloon beyond the imaging hood.

Abstract: A sentinel lymph node detecting apparatus 1 according to an embodiment of the present invention includes: a light source unit 2, illuminating an excitation light 10 and an illumination light 11 onto a biological observation location 20 that includes a sentinel lymph node 21 near a tumor, into which a fluorescent dye that emits fluorescence is injected; an optical filter 3, transmitting a fluorescence image 11 and a normal image 13; an image pickup device 5, disposed integral to the light source unit 2 and picking up the fluorescence image 11 and the normal image 13 transmitted through the optical filter 3; and an image display device 7, displaying the observation images that have been picked up. The wavelength of the illumination light 11 is set to a value close to the wavelength of the fluorescence emitted from the fluorescent dye.

Abstract: A method and apparatus for identifying tissue structures in advance of a mechanical medical instrument during a medical procedure. A mechanical tissue penetrating medical instrument (22) has a distal end for penetrating tissue in a penetrating direction. An optical wavefront analysis system (32-50) provides light to illuminate tissue ahead of the medical instrument and receives light returned by tissue ahead of the medical instrument. An optical fiber (30) is coupled at a proximal end to the wavefront analysis system and attached at a distal end to the medical instrument proximate the distal end of the medical instrument. The distal end of the fiber has an illumination pattern directed substantially in the penetrating direction for illuminating the tissue ahead of the medical instrument and receiving light returned therefrom. The wavefront analysis system provides information about the distance from the distal end of the medical instrument to tissue features ahead of the medical instrument.

Abstract: Needle interventions are widely used in the field of oncology for taking biopsies of tissue in order to inspect whether tissue is cancerous or not. To make these interventions more reliable feedback of what kind of tissue is in front of the needle is required. A way to achieve this is by making use of optical spectroscopy. This requires integration of fibers into the needle. These fibers are used to deliver light to illuminate the tissue in front of the needle and to collect back the reflected light from the tissue. The present invention proposes to integrate the fiber distal ends in the slanted bevel of the needle in such a way that at least one source-detector fiber pair has a distance that is larger than the outer diameter of the needle.

Abstract: A method for maintaining clear passageways in an extracorporeal blood flow system. The method comprises intermittently providing one or more anti-clotting agents to a passageway of the extracorporeal blood flow system. Also disclosed is an extracorporeal blood flow system. The system comprises a passageway, and a device operatively connected to provide one or more anti-clotting agents to a least a portion of said passageway.

Abstract: A catheter tip apparatus arranged in a catheter for the delivery and collection of a light-energy signal to permit subsequent computerized analysis of body tissue by the collected signal. The apparatus comprises an elongated housing supporting a first reflective surface and a second reflective surface. The first reflective surface and the second reflective surface are longitudinally spaced apart from one another. A first flexible, elongated energy bearing delivery fiber has a distalmost end arranged adjacent the first reflective surface. A second flexible, elongated energy bearing collection fiber has a distalmost end arranged adjacent the second reflective surface. The housing is rotatably supported on a flexible catheter sheath for insertion of the catheter into a mammalian body for tissue analysis thereof.

Abstract: Balloon probes, adapted for use in endoscopy and other medical procedures, are useful to obtain spectroscopic information reflected or emitted from a tissue of interest in the infrared spectral region. The information collected by the probe is useful in the diagnosis and treatment of disease. The invention also relates to methods utilizing these probes to analyze a surface of interest, in a minimally invasive manner, in connection with the diagnosis and treatment of disease.

Abstract: A method for analyzing mucosa structure with optical coherence tomography (OCT) is provided, and includes: (a) scanning a mucosa sample with optical coherence tomography; (b) choosing a lateral range from a two- or three-dimensional OCT image and analyzing all the A-scan intensity profiles in the lateral range; (c) calculating three indicators in each A-scan intensity profile, including the standard deviation for a certain depth range below the sample surface, the exponential decay constant of the spatial-frequency spectrum and the epithelium thickness under the condition that the basement membrane is identifiable; and (d) using the three indicators of each A-scan intensity profile within the lateral range to analyze the mucosa structure.

Abstract: A cannula can have a ferrule with two interspaced optical fiber passages extending therebetween, each securely housing an optical fiber therein having a first tip exposed at a connection end, and a second tip protruding from an opposite implant end by a penetration distance, and a bore extending into the ferrule from the connection end. The cannula can be removably connected by a patch cord having a ferrule with a guide pin, with a relatively high degree of optical alignment, by inserting both ferrules into corresponding ends of a sleeve and engaging the guide pin within the bore.

Abstract: A device for picture-providing diagnosis of tissue is selectively operated in a picture-providing white light diagnosis mode and a picture providing auto-fluorescence mode. A color camera having red, green, and blue sensors provides a monitor which picture signals. A light source emits fluorescence excitation light and additionally emits so much red light that the red light remitted by the tissue dominates the red fluorescence light in the picture providing auto-fluorescence mode. The signal from the red sensor of the camera is damped so that normal time appears green and pre-malignant and early malignant tissue appears red.

Abstract: Needles equipped with fibres allow tissue inspection based on optical spectroscopy to diagnose whether tissue is cancerous or not. This requires integration of optical fibers into needles. The problem is how to manufacture the needle having at least one fiber exit at the distal end of the needle, where the fiber does not obstruct the hollow part of the needle if present as well as does not extend beyond the outer cylinder geometry. To solve this problem we propose to manufacture the needle consisting of four parts: an inner cylinder tube, an outer hollow cylinder tube, a needle tip part with integrated fiber exit and a holder part, wherein the hollow spacing between the inner and the outer cylinder is larger or equal to the outer diameter of the fibers, the inner and the outer cylinder are mounted in the holder part and where the tip part is mounted on the two cylinders.

Abstract: A method of forming an optical fibre tip, the method including, roughening at least part of an end portion of the optical fibre; and, etching the roughed end portion to thereby form an optical fibre tip.

Abstract: A catheter with a fluorescent temperature sensor is shown and described. The catheter includes a lumen, a fiber-optic cable that extends through the lumen. A distal end of the fiber-optic cable is coated with a fluorescent material and a proximal end of the fiber-optic cable is connected to a console. The console includes a light source for transmitting light through the fiber-optic cable for exciting the fluorescent material. The console further includes a photo multiplier tube for converting light emitted by the excited fluorescent material to a plurality of analogue voltage signals. The console further includes a digital oscilloscope linked to the photo multiplier tube for converting the plurality of analogue voltage signals to at least one digital signal. The console further includes a processor linked to the digital oscilloscope for converting the at least one digital signal to a temperature value for the distal end of the fiber-optic cable.

Abstract: A method for sensitively diagnosing lower urinary tract disorders, particularly interstitial cystitis, is provided. The method can visually, simply, and clearly diagnose bladder ulcer without requirement of bladder hydrodistention under anesthesia. In the method, lower urinary tract disorders are diagnosed by observing an abnormality of a blood vessel and/or a newly formed blood vessel in a surface of bladder mucous membrane among abnormalities in blood vessels and/or newly formed blood vessels by visually comparing an image of the surface of the bladder mucous membrane and an image of a deep portion of the bladder mucous membrane obtained using a bladder endoscope system having a narrow band imaging device.

Abstract: An imaging transducer assembly is combined with a sensor of a medical positioning system, forming a transducer/sensor assembly. In one embodiment, the sensor includes a coil proximally coupled with the imaging transducer. A cable having first and second wires are proximally coupled to the coil. A non-conductive potting layer is wrapped around the coil. Traces are formed in the non-conductive potting layer that are used to electrically couple the imaging transducer with the first and second wires of the cable.

Abstract: A system and method for the in situ discrimination of healthy and diseased tissue. A fiberoptic based probe is employed to direct ultraviolet illumination onto a tissue specimen and to collect the fluorescent response radiation. The response radiation is observed at three selected wavelengths, one of which corresponds to an isosbestic point. In one example, the isosbestic point occurs at about 431 nm. The intensities of the observed signals are normalized using the 431 nm intensity. A score is determined using the ratios in a discriminant analysis. The tissue under examination is resected or not, based on the diagnosis of disease or health, according to the outcome of the discriminant analysis.

Abstract: A device elucidates reaction dynamics of photoreactive compounds present in a region of interest (ROI) of a tissue, the ROI being submitted to a controllably-varying and spatially homogenous magnetic field. The device includes at least one electrical coil or magnet for externally applying a magnetic field to the ROI. The device further includes light sources for probing the ROI with a probe optical beam and for illuminating the ROI with an optical beam having a wavelength and power level suitable for activating the photoreactive compounds. Collectors are also provided to collect the light emitted from various photoluminescence mechanisms that occur in the optically-activated ROI when the probe beam is incident on it and then to detect the collected light over predetermined wavelength bands. Finally, a computer is used to analyze the detected light for assessing the effects of the external magnetic field applied to the ROI.

Abstract: A spectroscope includes first and second beam redirectors in optical communication with first and second fibers respectively. The first and second beam redirectors are oriented to illuminate respective first and second areas. The second area is separated from the first area by a separation distance that exceeds the separation distance between the first and second beam redirectors.

Abstract: A pressure sensor (10 for medical applications comprises a silica optical fiber extrinsic Fabry-Perot interferometric (EFPI) pressure sensor (2) and an in-fiber Bragg grating (FBG, 3). The cavity of the EFPI pressure sensor (2) is formed by the end face of the FBG (3), a glass capillary (5) and a glass diaphragm (6). The glass diaphragm (6) is secured in place by a fusion splice (7) and the glass capillary (5) by a fusion splice (8). As illustrated, incident light is directed into the FBG 3 and there are reflections in the EFPI pressure sensor (2). Applied pressure causes a deflection of the glass diaphragm (6) and hence modulation of the EFPI sensor (2) cavity. The FBG (3) is used as a reference sensor to eliminate temperature cross-sensitivity of the EFPI pressure sensor (2). The EFPI cavity was fabricated using a 200 ?m silica glass fiber, a 133/220 ?m (inner/outer diameter) silica glass capillary and a standard telecommunication FBG.

Abstract: A portable device for observing a typological characteristic of the body. For example, the device can be used to observe at least one characteristic of the appearance of the skin or the hair. The device can generate at least two images of the zone under examination. The images differ from each other as to a feature other than magnification and the intensity of the light source.

Abstract: An optical coherence tomography system and method with integrated pressure measurement. In one embodiment the system includes an interferometer including: a wavelength swept laser; a source arm in communication with the wavelength swept laser; a reference arm in communication with a reference reflector; a first photodetector having a signal output; a detector arm in communication with the first photodetector, a probe interface; a sample arm in communication with a first optical connector of the probe interface; an acquisition and display system comprising: an A/D converter having a signal input in communication with the first photodetector signal output and a signal output; a processor system in communication with the A/D converter signal output; and a display in communication with the processor system; and a probe comprising a pressure sensor and configured for connection to the first optical connector of the probe interface, wherein the pressure transducer comprises an optical pressure transducer.

Abstract: The present invention provides an imaging probe for imaging mammalian tissues and structures using high resolution imaging, including ultrasound and optical coherence tomography. The imaging probe uses electrostatic discharge for actuating a metalized cantilever which holds the end portion of imaging assembly which emits energy in the imaging probe device by holding the cantilever at a potential such that it is neither grounded or charged such that the only electrical path to ground is through a dissipative polymer forming part of the device which is enveloped by a wire or coil held at ground potential. A high voltage electrode attracts the metalized cantilever and the dissipative polymer is used to connect to the cantilever to ground causing the cantilever to move about thereby scanning the region in front of the probe.

Abstract: Designs, implementations, and techniques for optically measuring a sample and integrated systems that provide CT-scan, optical probing and therapy by electromagnetic radiation treatment (e.g. laser, RF, or microwave). Light at different wavelength bands may be used to detect different absorption features in the sample. Multiple light sources may be used including tunable lasers.

Abstract: An exemplary system includes an implantable cochlear stimulator configured to be implanted within a patient, a sound processor communicatively coupled to the implantable cochlear stimulator and configured to direct the implantable cochlear stimulator to generate and apply electrical stimulation to one or more stimulation sites within a cochlea of the patient, and a displacement sensor assembly configured to measure a displacement of the stapedius of the patient that occurs in response to the application of the electrical stimulation and transmit displacement data representative of the measured displacement to the sound processor. Corresponding systems and methods are also disclosed.

Abstract: The present invention is directed to a two-dimensional scanning arrangement for a laser vein-illumination device that includes a base and a frame connected to the base using at least one flexible hinge. The hinge allows the frame to move angularly with respect to the base in a first direction. The invention further includes a means for exciting angular oscillations of the frame at or near said frame's resonant frequency. An elastic torsional element having a proximal end rigidly attached to said frame and a distal end rigidly attached to a mirror is also included. The torsional element allows the mirror to move angularly with respect to the frame in a second direction, generally perpendicular to the first direction. There may also be a means for exciting the angular oscillations of the mirror. The invention also includes a device for optically inspecting confined spaces having one or more small access orifices.

Abstract: The invention is a rotating tip catheter-imaging probe where electromagnetic energy is delivered to the distal end of a catheter and converted to mechanical energy using a light drive apparatus. The mechanical energy is then used to rotate a mirror that redirects light in fixed pattern on a sample. The rotating element of the light drive apparatus contains vanes, which rotate about an axis and positioned with bearings to minimize friction. A chamber encompasses the rotating element and is set to a vacuum pressure. The rotational speed of the catheter tip can be controlled by varying the optical power delivered to the vanes, the vacuum pressure in the chamber, or by a braking mechanism applied to the rotating element. The vanes may be shaped in a particular geometry to increase forces on the vanes from thermally driven gas flow.

Abstract: A fiber optic probe having one or more photodetectors bound thereto is provided. By directly integrating thin, flexible photodetectors with an optical fiber, the probes provide a compact structure that increases throughput and decreases cost, making it practical for a clinical use. In some embodiments, the fiber optic probes are small enough for insertion into the shaft of a needle, such as a biopsy needle.

Abstract: An optical probe, comprising: a sheath to be inserted into a body cavity; an optical fiber inside the sheath; an optical component attached to a distal end portion of the optical fiber inside the sheath; wherein a light beam transmitted through the optical fiber is emitted from the optical component toward a body tissue in the body cavity, and wherein the sheath comprises a plurality of balloons spaced at predetermined intervals on a part on the distal end portion side of an outer periphery and capable of inflating/deflating in a radial direction orthogonal to a longitudinal axis, a suction inlet located between the plurality of balloons to draw the body tissue at the part on the distal end portion side of the outer periphery by suction, a balloon inflation port connected to the balloons, and a suction port connected to the suction inlet, and the plurality of balloons are airtightly locked to an body cavity inner wall by supplying a fluid or a gas through the balloon inflation port to pressurize and inflat

Abstract: The present invention relates to fiberoptic sensors embedded within a surgical drain to monitor the condition of tissue proximate to the surgical drain and methods of processing data from the sensors. The light transmitting and collecting tips of the optical fibers are adapted to enable sideways interrogation of the adjacent tissues using optical techniques to measure the tissue condition. The light transmitting and collecting tips of the optical fibers may be bent at angle, disposed between a light absorbing and transmitting sheets, or uncladded to enable sideways emission and collection of light. Processing methods for reducing the site dependency of the measured data, maximizing the signal to noise ratio, and increasing the measurement sensitivity to changes in the tissue condition are described.

Abstract: Tissue closure systems are described herein. Such a system may include a deployment catheter and an attached imaging hood deployable into an expanded configuration. In use, the imaging hood is placed against or adjacent to a region of tissue to be imaged in a body lumen that is normally filled with an opaque bodily fluid such as blood. A translucent or transparent fluid, such as saline, can be pumped into the imaging hood until the fluid displaces any blood, thereby leaving a clear region of tissue to be imaged via an imaging element in the deployment catheter. Additionally, the system can be deployed in a number of various ways to effect the closure of wounds or openings in the patient body.

Abstract: Apparatus is provided for diagnosing or treating an organ or vessel, wherein a device having at optical fiber contact force sensors disposed in a distal extremity thereof and a deflection mechanism configured to deflect the elongate body at a location proximal of the distal extremity. The optical fiber contact force sensors are configured to be coupled to processing logic programmed which computes a force vector responsive to detected changes in the optical characteristics of the optical fiber contact force sensors arising from deflection of the distal extremity resulting from contact with the tissue of the wall of the organ or vessel.

Abstract: An optical scanning probe is provided and includes a housing, a diaphragm disposed in the housing, a rotor, a conduit, an optical fiber module, and a reflector disposed on the rotor, wherein the diaphragm and the housing forms a chamber. The rotor is movably disposed in the chamber and has several fans. The conduit is disposed in the housing to conduct fluid into the chamber, thus impelling the fans and the rotor. The optical fiber module is disposed in the housing and through the diaphragm to transmit a light beam. The reflector rotates with the rotor and reflects the light beam for 360° scanning.

Abstract: A method and system for determination and mapping the quantity of chromophores having a distinct spectrum attached to moving objects in an spectrally rich environment that may include multiple chromophores attached to stationary objects. Au area of interest is imaged at different times and different wavelengths, and the spectral properties of the chromophores attached to the moving objects are separated from the stationary spectral properties of the background, followed by spectral analysis of the moving objects to determine their quantity. Application to the retinal vasculature is illustrated, showing the imaging, analyzing and quantifying of the oxygen saturation of retinal blood, resolved for the different vascular compartments, including capillaries, arterioles, venules, arteries, and veins.

Abstract: Techniques, apparatus and systems that use an optical probe head to deliver light to a target and to collect light from the target for imaging and monitoring a target while a separate radiation is applied to treat the target.

Abstract: Systems and methods for marking a body cavity. In one embodiment, a system includes means for inspecting a body cavity, and means for visibly marking the body cavity so as to convey visual information regarding the body cavity. In one embodiment, a method includes inspecting a body cavity and marking the body cavity with a marking material to provide a visual indication regarding the cavity. In one embodiment, a marking material for marking a body cavity includes a radiopaque contrast agent that is viewable through fluoroscopy and a colored dye that is viewable using an internal viewing device.

Abstract: A photodynamic mapping device includes a shaft with a proximal end and a distal end, at least one optical electrode at the distal end of the shaft, and at least one optical fiber positioned inside the shaft. In embodiments, the at least one optical fiber extends from the distal end of the shaft and is coupled to the at least one optical electrode provided at or about an outer surface of the device. In an embodiment, at least one optical fiber is coupled, at or about the proximal end of the shaft, to a light source coupled and an optical sensor. An analyzer can be coupled to the optical sensor. Embodiments of such devices can be configured to deliver substances, such as photodynamic therapeutic substances.

Abstract: A rod lens is used for fitting in an endoscopes. The rod lens has a rod-shaped body which is made at least in a section of a flexible, transparent solid piece of plastic material.

Abstract: Catheter-based Optical Coherence Tomography (OCT) systems utilizing an optical fiber that is positioned off-axis of the central longitudinal axis of the catheter have many advantage over catheter-based OCT systems, particularly those having centrally-positioned optical fibers or fibers that rotate independently of the elongate body of the catheter. An OCT system having an off-axis optical fiber for visualizing the inside of a body lumen may be rotated with the body of the elongate catheter, relative to a handle portion. The handle may include a fiber management pathway for the optical fiber that permits the off-axis optical fiber to rotate with the catheter body relative to the handle. The system may also include optical processing elements adapted to prepare and process the OCT image collected by the off-axis catheter systems described herein.

Abstract: The invention relates to a method for the fabric using an acquisition system that includes at acquisition of in-vivo fluorescence imaging from a least one optical fibre exciting the fabric by scanning light beam. According to the invention, the system is used to detect fluorescence signals emitted by the Methylene Blue present in the fabric.

Abstract: Embodiments of the present invention include a laser catheter that includes a catheter body, a light guide, and a distal tip that extends beyond the exit aperture of the light guide. In some embodiments, an imaging device is disposed on the distal tip such that the imaging device is distal relative to the exit aperture of the light guide. In some embodiments, the imaging device can be gated to record images during and/or slightly beyond periods when the laser catheter is not activated.

Abstract: An endoscopic swept-source Fourier Domain optical coherence tomographic system (FDOCT system) for imaging of tissue structure includes a Fourier Domain mode locked (FDML), high speed, narrow line-width, wavelength swept source, an OCT interferometer having a sample arm, a reference arm, a detection arm, and a source arm coupled to the swept source, an endoscopic probe coupled to the sample arm, and a data processing circuit coupled to the detection arm. The swept source includes a long optic fiber functioning as a cavity, a high optical gain lasing module, and a tunable narrow bandwidth bandpass filter for wavelength selection combined to form a unidirectional ring laser cavity, where the tunable narrow bandwidth bandpass filter is driven synchronously with the optical round-trip time of a propagating light wave in the cavity.

Abstract: Methods for diagnosing vulnerable atherosclerotic plaque using optical coherence tomography to measure tissue optical properties, including backreflectance of heterogeneous layers, such as plaque cap, lipid pool composition and macrophage presence. Methods also include measurement of spatially and temporally dependent reflectance, measurement of multiple wavelength reflectance, low coherence interferometry, polarization and quantification of macrophage content.

Abstract: Tissue imaging and extraction systems are described herein. Such a system may include a deployment catheter and an attached imaging hood deployable into an expanded configuration. In use, the imaging hood is placed against or adjacent to a region of tissue to be imaged in a body lumen that is normally filled with an opaque bodily fluid such as blood. A translucent or transparent fluid, such as saline, can be pumped into the imaging hood until the fluid displaces any blood, thereby leaving a clear region of tissue to be imaged via an imaging element in the deployment catheter. Additionally, the extraction system can include features or instruments for procedures such as clearing blood clots, emboli, and other debris which may be present in a body lumen. Other variations may also be used for facilitating trans-septal access across tissue regions as well as for balancing body fluids during a procedure.