Showing papers on "Optical coherence tomography published in 1997"
TL;DR: Optical coherence tomography was adapted to allow high-speed visualization of tissue in a living animal with a catheter-endoscope 1 millimeter in diameter, and was used to obtain cross-sectional images of the rabbit gastrointestinal and respiratory tracts at 10-micrometer resolution.
Abstract: Current medical imaging technologies allow visualization of tissue anatomy in the human body at resolutions ranging from 100 micrometers to 1 millimeter. These technologies are generally not sensitive enough to detect early-stage tissue abnormalities associated with diseases such as cancer and atherosclerosis, which require micrometer-scale resolution. Here, optical coherence tomography was adapted to allow high-speed visualization of tissue in a living animal with a catheter-endoscope 1 millimeter in diameter. This method, referred to as "optical biopsy," was used to obtain cross-sectional images of the rabbit gastrointestinal and respiratory tracts at 10-micrometer resolution.
1,415 citations
TL;DR: Using a low-coherence Michelson interferometer, the authors measured two-dimensional images of optical birefringence in bovine tendon as a function of depth, which allowed rapid noncontact investigation of tissue structural properties.
Abstract: Using a low-coherence Michelson interferometer, we measure two-dimensional images of optical birefringence in bovine tendon as a function of depth. Polarization-sensitive detection of the signal formed by interference of backscattered light from the sample and a mirror in the reference arm give the optical phase delay between light that is propagating along the fast and slow axes of the birefringent tendon. Images showing the change in birefringence in response to laser irradiation are presented. The technique permits rapid noncontact investigation of tissue structural properties through two-dimensional imaging of birefringence.
963 citations
TL;DR: In this article, a simple wide-optical-bandwidth, high-resolution system for performing rapid optical frequency domain reflectometry measurements and applied it to multidimensional tomographic imaging is presented.
Abstract: We have developed a simple, wide-optical-bandwidth, high-resolution system for performing rapid optical frequency domain reflectometry measurements and applied it to multidimensional tomographic imaging. The source is a grating-tuned external cavity semiconductor laser with a tuning capability of 25 nm in 100 ms. We discuss system performance and show a two-dimensional optical coherence tomography image of a thin glass sandwich structure as a preliminary demonstration of the systems depth and resolution capabilities.
841 citations
TL;DR: In this article, a color Doppler optical coherence tomography (CDOCT) was proposed for in vivo image of blood flow in a hamster subdermal tissue.
Abstract: We describe a novel optical system for bidirectional color Doppler imaging of flow in biological tissues with micrometer-scale resolution and demonstrate its use for in vivo imaging of blood flow in an animal model. Our technique, color Doppler optical coherence tomography (CDOCT), performs spatially localized optical Doppler velocimetry by use of scanning low-coherence interferometry. CDOCT is an extension of optical coherence tomography (OCT), employing coherent signal-acquisition electronics and joint time-frequency analysis algorithms to perform flow imaging simultaneous with conventional OCT imaging. Cross-sectional maps of blood flow velocity with <50-µm spatial resolution and <0.6-mm/s velocity precision were obtained through intact skin in living hamster subdermal tissue. This technology has several potential medical applications.
643 citations
TL;DR: The grating-based phase-control delay line is discussed, which is especially well suited for applications such as optical coherence tomography that require high-speed, repetitive, linear delay line scanning with a high duty cycle.
Abstract: A rapid-scanning optical delay line that employs phase control has several advantages, including high speed, high duty cycle, phase- and group-delay independence, and group-velocity dispersion compensation, over existing optical delay methods for interferometric optical ranging applications. We discuss the grating-based phase-control delay line and its applications to interferometric optical ranging and measurement techniques such as optical coherence domain reflectometry and optical coherence tomography. The system performs optical ranging over an axial range of 3 mm with a scanning rate of 6m/s and a repetition rate of 2 kHz. The device is especially well suited for applications such as optical coherence tomography that require high-speed, repetitive, linear delay line scanning with a high duty cycle.
585 citations
TL;DR: The development of an optical technique for noninvasive imaging of in vivo blood flow dynamics and tissue structures with high spatial resolution (2-10 microm) in biological systems based on optical Doppler tomography (ODT).
Abstract: We report the development of an optical technique for noninvasive imaging of in vivo blood flow dynamics and tissue structures with high spatial resolution (2-10 microm) in biological systems. The technique is based on optical Doppler tomography (ODT), which combines Doppler velocimetry with optical coherence tomography to measure blood flow velocity at discrete spatial locations. The exceptionally high resolution of ODT permits noninvasive in vivo imaging of both blood microcirculation and tissue structures surrounding the vessel, which has significance for biomedical research and clinical applications. Tomographic imaging of in vivo blood flow velocity in the chick chorioallantoic membrane and in rodent skin is demonstrated.
579 citations
TL;DR: An optical Doppler tomography (ODT) system that permits imaging of fluid flow velocity in highly scattering media is described andTomographic imaging of particle flow velocity within a circular conduit submerged 1 mm below the surface in a highly scattering phantom of Intralipid is demonstrated.
Abstract: An optical Doppler tomography (ODT) system that permits imaging of fluid flow velocity in highly scattering media is described. ODT combines Doppler velocimetry with the high spatial resolution of low-coherence optical interferometry to measure fluid flow velocity at discrete spatial locations. Tomographic imaging of particle flow velocity within a circular conduit submerged 1 mm below the surface in a highly scattering phantom of Intralipid is demonstrated.
485 citations
TL;DR: OCT is a promising new imaging method for visualization of morphologic changes of superficial layers of the human skin that may be useful for noninvasive diagnosis of bullous skin diseases, skin tumors, and in vivo investigation of pharmacologic effects.
Abstract: Background: Optical coherence tomography (OCT) is a new diagnostic method for tissue characterization. Objective: We investigated normal and pathologic structures in human skin in several locations to evaluate the potential application of this technique to dermatology. Methods: Based on the principle of low-coherence interferometry, cross-sectional images of the human skin can be obtained in vivo with a high spatial resolution of about 15 μm. Within a penetration depth of 0.5 to 1.5 mm, structures of the stratum corneum, the living epidermis, and the papillary dermis can be distinguished. Results: Different layers could be detected that were differentiated by induction of experimental blisters and by comparison with corresponding histologic sections. Furthermore, OCT images of several skin diseases and tumors were obtained. Conclusion: OCT is a promising new imaging method for visualization of morphologic changes of superficial layers of the human skin. It may be useful for noninvasive diagnosis of bullous skin diseases, skin tumors, and in vivo investigation of pharmacologic effects. (J Am Acad Dermatol 1997;37:958-63.)
429 citations
TL;DR: In this paper, the authors compared OCT and intravascular ultrasound (IVUS) imaging of in vitro atherosclerotic plaques and found that OCT yielded superior structural information in all plaques examined.
Abstract: BACKGROUND: OCT can image plaque microstructure at a level of resolution not previously demonstrated with other imaging techniques because it uses infrared light rather than acoustic waves. OBJECTIVES: To compare optical coherence tomography (OCT) and intravascular ultrasound (IVUS) imaging of in vitro atherosclerotic plaques. METHODS: Segments of abdominal aorta were obtained immediately before postmortem examination. Images of 20 sites from five patients were acquired with OCT (operating at an optical wavelength of 1300 nm which was delivered to the sample through an optical fibre) and a 30 MHz ultrasonic transducer. After imaging, the microstructure of the tissue was assessed by routine histological processing. RESULTS: OCT yielded superior structural information in all plaques examined. The mean (SEM) axial resolution of OCT and IVUS imaging was 16 (1) and 110 (7), respectively, as determined by the point spread function from a mirror. Furthermore, the dynamic range of OCT was 109 dB compared with 43 dB for IVUS imaging. CONCLUSIONS: OCT represents a promising new technology for intracoronary imaging because of its high resolution, broad dynamic range, and ability to be delivered through intravascular catheters.
364 citations
TL;DR: In this article, a comprehensive model of optical coherence tomography (OCT) is described that includes the interference effects that produce speckle in images of dense heterogeneous tissue.
Abstract: A comprehensive model of optical coherence tomography (OCT) is described that includes the interference effects that produce speckle in images of dense heterogeneous tissue. It is based on the extended Huygens–Fresnel formulation of beam propagation in a turbulent atmosphere, adapted to the analysis of OCT. Incorporated in the model is a fractal description of the size distribution of scatterers in tissue. We demonstrate its application in the simulation of images of tissue volumes containing high-contrast targets embedded in a mixture of two sizes of particles. The simulated images show the degradation of image quality caused by speckle noise, along with the benefits of employing a light source with a short coherence time and an objective lens with a high numerical aperture. Based on model results, an estimate of the maximum probing depth is given in terms of the design variables of an OCT scanner and the optical properties of the tissue.
297 citations
TL;DR: The design and implementation of forward-imaging instruments for optical coherence tomography (OCT), which require the delivery, scanning, and collection of single-spatial-mode optical radiation, are discussed.
Abstract: We discuss the design and implementation of forward-imaging instruments for optical coherence tomography (OCT), which require the delivery, scanning, and collection of single-spatial-mode optical radiation. A hand-held surgical probe for use in open surgery can provide cross-sectional images of subsurface tissue before surgical incisions are made. A rigid laparoscope for minimally invasive surgical OCT imaging provides a simultaneous en face view of the area being imaged. OCT imaging is demonstrated on in vitro human specimens.
TL;DR: A reconstruction method which overcomes fundamental limitations on Doppler flow mapping associated with both high- and low-speed imaging and is successful in retaining the high velocity resolution of CDOCT while eliminating motion artifact caused by slow image acquisition in samples which exhibit repetitive motion.
Abstract: Color Doppler optical coherence tomography (CDOCT) is a noninvasive technique for simultaneous high spatial resolution (~20 μm) imaging and high velocity resolution (~500 μm/s) imaging flowmetry in living tissues. In this paper, we demonstrate a reconstruction method which overcomes fundamental limitations on Doppler flow mapping associated with both high- and low-speed imaging. This algorithm is successful in retaining the high velocity resolution of CDOCT while eliminating motion artifact caused by slow image acquisition in samples which exhibit repetitive motion. We demonstrate reconstruction of blood flow throughout a beating Xenopus laevis heart and surrounding vasculature using gated CDOCT reconstruction.
Journal Article•
TL;DR: The ability of OCT to provide high-resolution in situ imaging of gastrointestinal microstructure, without the need for excisional biopsy, suggests the feasibility of using OCT as a powerful diagnostic imaging technology, which can be integrated with conventional endoscopy.
TL;DR: Comparing cross-sectional images of primate retinal morphology obtained by optical coherence tomography with light microscopy to determine the retinal components represented in OCT images demonstrated reproducible patterns ofretinal morphology that corresponded to the location of retinal layers seen on light microscopic overlays.
Abstract: Objective: To compare the cross-sectional images of primate retinal morphology obtained by optical coherence tomography (OCT) with light microscopy to determine the retinal components represented in OCT images. Methods: Laser pulses were delivered to the retina to create small marker lesions in a Macaca mulatta . These lesions were used to align in vivo OCT scans and ex vivum histologic cross sections for image comparison. Results: The OCT images demonstrated reproducible patterns of retinal morphology that corresponded to the location of retinal layers seen on light microscopic overlays. Layers of relative high reflectivity corresponded to horizontally aligned retinal components such as the nerve fiber layer and plexiform layers, as well as to the retinal pigment epithelium and choroid. In contrast, the nuclear layers and the photoreceptor inner and outer segments demonstrated relative low reflectivity by OCT. Conclusions: Retinal morphology and macular OCT imaging correlate well, with alignment of areas of high and low reflectivity to specific retinal and choroidal elements. Resolution of retinal structures by OCT depends on the contrast in relative reflectivity of adjacent structures. Use of this tool will enable expanded study of retinal morphology, both normal and pathologic, as it evolves in vivo.
Patent•
31 Dec 1997TL;DR: In this paper, an optical coherence tomography (OCT) and spectral interferometry imaging probe for automatic screening and diagnosis of cervical and skin cancer in vivo was proposed.
Abstract: An optical coherence tomography(OCT) and spectral interferometry imaging probe for the automatic screening and diagnosis of cervical and skin cancer in vivo. The probe eliminates the old techniques of having to perform Pap smears followed by a biopsy, known as colposcopy. The novel probe is cylindrical in shape and has a disposable outer plastic shield. Inside the probe is a motor driven rotatable casing having a planar optical fiber bundle array therein. The fiber bundle array has plastic light coupling lenslet arrays on both ends. The exposed end of the probe has one lenslet array disc that couples light between the probe and an interior of the cervix area being examined. Both the casing and the bundle array rotate relative to the outer probe walls. Inside the casing is a rotatable motor driven scanning mirror which couples passes light from an incoming second fiber bundle array to the lenslet array on the inside end of the rotatable casing fiber bundle array. The incoming second fiber bundle array is attached to a detector located external and remote to the probe. The detector has a tunable light source and a spectrometer for providing 3-D images of the interior of the cervix. The proposed technique of simultaneous OCT imaging and spectral interferometry and analysis has potential use in either multi-layer optical disk read out using low coherence tomography and spectral interferometry. Alternatively, by employing spectral interferometry, the measured optical spectrum also provides a unique mapping of the recorded bits into the observed spectral modulation. The unique feature is that by simultaneously employing both spectral interferometry and low coherence tomography, the resultant data transfer rate is increased, but the combination also allows for error rate analysis.
01 Jan 1997
TL;DR: The ability of OCT to provide non-contact high resolution imaging of urologic tissue architectural morphology (i.e. optical biopsy), without the need for excisional biopsy, suggests the potential of using OCT to obtain information on tissue microstructure that could only previously be obtained with conventional biopsy.
TL;DR: In this paper, optical coherence tomography (OCT) was introduced for the high-resolution assessment of structure and function in the developing Xenopus laevis cardiovascular system.
Abstract: Studies investigating normal and abnormal cardiac development are frequently limited by an inability to assess cardiovascular function within the intact organism. In this work, optical coherence tomography (OCT), a new method of micron-scale, noninvasive imaging based on the measurement of backscattered infrared light, was introduced for the high resolution assessment of structure and function in the developing Xenopus laevis cardiovascular system. Microstructural details, such as ventricular size and wall positions, were delineated with OCT at 16-μm resolution and correlated with histology. Three-dimensional representation of the cardiovascular system also was achieved by repeated cross-sectional imaging at intervals of 25 μm. In addition to structural information, OCT provides high speed in vivo axial ranging and imaging, allowing quantitative dynamic activity, such as ventricular ejection fraction, to be assessed. The sensitivity of OCT for dynamic assessment was demonstrated with an inotropic agent that altered cardiac function and dimensions. Optical coherence tomography is an attractive new technology for assessing cardiovascular development because of its high resolution, its ability to image through nontransparent structures, and its inexpensive portable design. In vivo and in vitro imaging are performed at a resolution approaching that of histopathology without the need for animal killing.
TL;DR: Experimental results are presented showing that the size and distribution of small subsurface defects can be determined with depth and lateral resolutions of 10 and 4 microm, respectively.
Abstract: We use optical coherence tomography with a new configuration to determine the size and location of subsurface defects in solid ceramic and composite ceramic materials. Cross-sectional subsurface regions either parallel or perpendicular to the surface were examined. We present experimental results showing that the size and distribution of small subsurface defects can be determined with depth and lateral resolutions of 10 and 4 microm, respectively.
01 Jan 1997
TL;DR: In this paper, the authors used OCT for the high resolution assessment of structure and function in the developing mammalian cardiovascular system, and demonstrated the sensitivity of OCT for dynamic assessment with an inotropic agent that altered cardiac function and dimensions.
Abstract: Studies investigating normal and abnormal cardiac development are frequently limited by an inability to assess cardiovascular function within the intact organism. In thiswork,opticalcoherencetomography(OCT),anewmethod of micron-scale, noninvasive imaging based on the measure- ment of backscattered infrared light, was introduced for the high resolution assessment of structure and function in the developingXenopus laeviscardiovascular system. Microstruc- tural details, such as ventricular size and wall positions, were delineatedwithOCTat16-mmresolutionandcorrelatedwith histology.Three-dimensionalrepresentationofthecardiovas- cular system also was achieved by repeated cross-sectional imaging at intervals of 25 mm. In addition to structural information, OCT provides high speed in vivo axial ranging and imaging, allowing quantitative dynamic activity, such as ventricular ejection fraction, to be assessed. The sensitivity of OCT for dynamic assessment was demonstrated with an inotropic agent that altered cardiac function and dimensions. Opticalcoherencetomographyisanattractivenewtechnology for assessing cardiovascular development because of its high resolution, its ability to image through nontransparent struc- tures, and its inexpensive portable design.In vivoandin vitro imaging are performed at a resolution approaching that of histopathology without the need for animal killing.
TL;DR: A novel noninvasive second-harmonic-generation tomographic method of mapping the structure of animal tissues by use of 100-fs laser pulses at 625nm is described, which is potentially a symmetry-sensitive tool for optical histological reconstruction.
Abstract: A novel noninvasive second-harmonic-generation tomographic method of mapping the structure of animal tissues by use of 100-fs laser pulses at 625nm is described. Subsurface structures were measured with this approach, which is potentially a symmetry-sensitive tool for optical histological reconstruction.
Patent•
14 May 1997TL;DR: In optical coherence tomography, a light beam scans the object along a x-line on the surface, and the depth from which light of intensity I is reflected is measured by means of a partial-coherence interferometer as mentioned in this paper.
Abstract: In optical coherence tomography, a sectional image I(x,z) of an object is obtained in that a light beam scans the object along a x-line on the surface, and the depth z from which light of intensity I is reflected is measured by means of a partial-coherence interferometer In so doing, a strong medium intensity can cover and conceal small differences in adjacent object points The invention renders small differences in adjacent object points visible in that the object is illuminated by a dual beam which simultaneously illuminates the object at two adjacent points and whose two components are in opposite phase after traversing the arrangement, so that they cancel one another in a homogeneous object structure On the other hand, if changes are brought about in the two light bundles by means of the reflectance at the object structure, they do not cancel one another, but rather produce an image signal
TL;DR: Continuous-wave ultrasonic modulation of scattered laser light was used to image objects buried in tissue-simulating turbid media and the dependence of the ultrasound-modulated optical signal on the off-axis distance from the optic axis and the area of the detector was studied.
Abstract: Continuous-wave ultrasonic modulation of scattered laser light was used to image objects buried in tissue-simulating turbid media. The buried object had an absorption coefficient greater than the background turbid medium. The ultrasonic wave that was focused into the turbid media modulated the laser light that passed through the ultrasonic field. The modulated laser light that was collected by a photomultiplier tube reflected the local mechanical and optical properties in the zone of ultrasonic modulation. Objects buried in the middle plane of 5-cm-thick dense turbid media were imaged with millimeter resolution through the scanning and detecting alterations of the ultrasound-modulated optical signal. The optical properties of the dense turbid media included an absorption coefficient of 0.1 cm-1 and a reduced scattering coefficient of 10 cm-1 and were comparable with those of biological tissues in the visible and near-IR ranges. The dependence of the ultrasound-modulated optical signal on the off-axis distance of the detector from the optic axis and the area of the detector was studied as well.
TL;DR: The ability of OCT to provide micrometer-scale definition of tissue microstructure suggests a role in surgical diagnostics, and future in vivo investigations are merited to establish its utility for morbidity reduction associated with surgical intervention.
TL;DR: Novel coherence-domain imaging techniques provide the capability for rapid, noninvasive imaging of microscopic sub-surface structures and blood flows in living biological tissues in order to provide the medical profession with new diagnostic tools.
Abstract: Novel coherence-domain imaging techniques provide the capability for rapid, noninvasive imaging of microscopic sub-surface structures and blood flows in living biological tissues. The authors describe recent advances in optical coherence tomography (OCT), optical coherence microscopy (OCM), and color Doppler OCT (shown above) as means to provide the medical profession with new diagnostic tools.
TL;DR: The novel sequential imaging of rapidly evolving macular lesions with optical coherence tomography provides new insight into the patterns of acute tissue response by cross-sectional layer.
TL;DR: A short introduction to optical ocular tomography or optical coherence tomography (OCT) and a survey of recent applications and the basic principles are explained and the information content of OCT images is discussed.
Abstract: This paper gives a short introduction to optical ocular tomography or optical coherence tomography (OCT) and a survey of recent applications. The basic principles are explained and the information content of OCT images is discussed.
TL;DR: The imaging contrast is limited by multiple scattering and speckle effects in high-scattering media, and the measured effective penetration depth of optical coherence tomography is approximately equal to six mean free paths under the experimental conditions of a numerical aperture and a scattering anisotropy of approximately 0.8.
Abstract: The fundamental difference between time-resolved and coherence-gated imaging modalities in scattering media is analyzed in terms of their optical transfer functions. The effectiveness of coherence gating for multiple-scattering rejection is shown by imaging a 100-mum-thick razor blade hidden in the scattering phantoms (i.e., Intralipid suspensions) with different scattering coefficients. We found that the imaging contrast is limited by multiple scattering and speckle effects in high-scattering media, and the measured effective penetration depth of optical coherence tomography is approximately equal to six mean free paths under the experimental conditions of a numerical aperture of less than 0.1 and a scattering anisotropy of approximately 0.8.
22 May 1997
TL;DR: In this article, a near-infrared coherent imaging technique that can reveal scattering bodies embedded in highly scattering media is presented, which is extended from frequency modulated continuous wave radar systems.
Abstract: A new near-infrared coherent imaging technique that can reveal scattering bodies embedded in highly scattering media is presented. Its underlying principle is extended from frequency modulated continuous wave radar systems. This technique has advantages over low coherence tomography as it does not require the reference mirror to be scanned. The tunable laser is characterized and the system's performance is demonstrated on images recorded from solid scattering phantoms. Furthermore a combination of our chirp-tomography (C-OCT) and laser Doppler perfusion imaging (LDPI) is demonstrated. The influence of moving scatterers on the tomographic images are discussed.© (1997) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
TL;DR: In this article, the authors investigated the suitability and limits of OCT for measuring the cornea and the anterior segment of the eye, and determined the stromal expansion of thermally induced lesions in cornea directly after irradiation within the scope of laser thermokeratoplasty.
Abstract: TARGET The method of optical coherence tomography (OCT) was investigated regarding its suitability and limits for measuring the cornea and the anterior segment of the eye. Furthermore, the stromal expansion of thermally induced lesions in the cornea directly after irradiation was determined within the scope of the laser thermokeratoplasty (LTK). MATERIAL AND METHODS With the experimental scanning OCT system, x-z sections of the anterior eye segment were made with an optical resolution of about 20 microns axially and 25 microns laterally. Freshly enucleated, tonicized porcine eyes were used as model eyes. Thermal lesions were applied with a continuously emitting laser diode (lambda = 1.86 microns) and various radiation parameters. Before and after coagulation, the cornea was viewed from limbus to limbus in a central OCT scan and the individual coagulation source was measured. RESULTS Global and local changes of the thickness of the cornea as well as the distance between cornea and lens were measured with high precision. Thermal lesions in their expansion can be dearly presented and matching well with the histologically stained sections, but are not as exactly defined at the edges due to the limited optical resolution, as known from histological preparations. CONCLUSION With the OCT method quantitative measuring of the anterior eye segment can be performed in vitro and with reduced resolutions also in vivo. Due to the qualitatively good correspondence regarding the dimensions of thermal damage of the cornea with histologically obtained morphometric results, this method can be used for supervision of coagulation directly after LTK as well as for examination of the individual healing process.