Conventional Optical Coherence Tomography Images Research Articles

Enhancement of OCT en face images by unsupervised deep learning

Objective. The quality of optical coherence tomography (OCT) en face images is crucial for clinical visualization of early disease. As a three dimensional and coherent imaging, defocus and speckle noise are inevitable, which seriously affect evaluation of microstructure of bio-samples in OCT images. The deep learning has demonstrated great potential in OCT refocusing and denoising, but it is limited by the difficulty of sufficient paired training data. This work aims to develop an unsupervised method to enhance the quality of OCT en face images. Approach. We proposed an unsupervised deep learning-based pipeline. The unregistered defocused conventional OCT images and focused speckle-free OCT images were collected by a home-made speckle modulating OCT system to construct the dataset. The image enhancement model was trained with the cycle training strategy. Finally, the speckle noise and defocus were both effectively improved. Main results. The experimental results on complex bio-samples indicated that the proposed method is effective and generalized in enhancing the quality of OCT en face images. Significance. The proposed unsupervised deep learning method helps to reduce the complexity of data construction, which is conducive to practical applications in OCT bio-sample imaging.

Vitreous mobility during the posterior vitreous detachment initiation demonstrated by pseudo-motion optical coherence tomography

PurposeTo document the anatomical changes occurring at the vitreoretinal interface during early posterior vitreous detachment (PVD). MethodsWide-angle and pseudo-motion optical coherence tomography (OCT) were obtained on 27 normal eyes during the early stages of age-related PVD. The wide-angle examination in a static phase consisted of montaged conventional OCT images. GIF-formatted pseudo-animation was generated with OCT images acquired initially in a static eye state, followed by scans immediately after ocular excursions. ResultsInitial stages of PVD included peripheral PVD with (stage 1a) or without (stage 1b) interposed material between the posterior vitreous cortex and the retina, and perifoveal PVD expanding to the periphery (stage 2). All stage 1 PVDs presented anterior to the papillomacular vitreous liquefaction. All eyes demonstrated mobility of the vitreous gel at the anterior face of the vitreous liquefaction; however, the adherent cortical vitreous layer comprising the posterior wall of the lacuna showed no mobility. Mobility of the posterior vitreous cortex was not present in eyes with stage 1a PVD and increased with the progression of the stage of PVD (p = 3.60×10−6). ConclusionDuring nonpathological PVD, macula is protected from tractional insults conveyed by mobile vitreous due to overlying vitreous liquefaction. However, the vitreoretinal interface anterior to the lacunae experiences tractional forces until vitreoretinal separation occurs. These observations reinforce the hypothesis that vitreous liquefaction, vitreous mobility, and vitreoschisis formation contribute to PVD initiation and support that premacular lacunae protect the macula during PVD initiation and early progression.

Plaque burden estimated from optical coherence tomography with deep learning: In vivo validation using co-registered intravascular ultrasound.

The objective of the present study was to compare plaque burden (PB) calculated from optical coherence tomography (OCT) using deep learning (DL) with PB derived from co-registered intravascular ultrasound (IVUS). A DL algorithm was developed for automated plaque characterization and PB quantification from OCT images. However, the performance of this algorithm for PB quantification has not been validated. Five-year follow-up OCT and IVUS images from 15 patients implanted with bioresorbable vascular scaffold (BVS) at baseline were analyzed. Precise co-registration for 72 anatomical slices was achieved utilizing unique BVS radiopaque markers. PB derived from OCT DL and IVUS were compared. OCT cross-sections were divided into four subgroups with different media visibility level. The impact of media visibility on the numerical difference between OCT-derived and IVUS-derived PB was investigated. The stent sizes selected by OCT DL and IVUS were compared. Sixty-four paired OCT and IVUS cross-sections were compared. OCT DL showed good concordance with IVUS for PB assessment (ICC = 0.81, difference = -3.53 ± 6.17%, p < 0.001). The numerical difference between OCT DL-derived PB and IVUS-derived PB was not substantially impacted by missing segments of media visualization (p = 0.21). OCT DL showed a diagnostic accuracy of 92% in identifying PB > 65%. The stent sizes selected by OCT DL were smaller compared to the ones selected by IVUS (difference = 0.30 ± 0.34 mm, p < 0.001). The DL algorithm provides a feasible and reliable method for automated PB estimation from OCT, irrespective of media visibility. OCT DL showed good diagnostic accuracy in identifying PB > 65%, revealing its potential to complement conventional OCT imaging.

Intravascular optical coherence elastography.

Optical coherence elastography (OCE), a functional extension of optical coherence tomography (OCT), visualizes tissue strain to deduce the tissue's biomechanical properties. In this study, we demonstrate intravascular OCE using a 1.1 mm motorized catheter and a 1.6 MHz Fourier domain mode-locked OCT system. We induced an intraluminal pressure change by varying the infusion rate from the proximal end of the catheter. We analysed the pixel-matched phase change between two different frames to yield the radial strain. Imaging experiments were carried out in a phantom and in human coronary arteries in vitro. At an imaging speed of 3019 frames/s, we were able to capture the dynamic strain. Stiff inclusions in the phantom and calcification in atherosclerotic plaques are associated with low strain values and can be distinguished from the surrounding soft material, which exhibits elevated strain. For the first time, circumferential intravascular OCE images are provided side by side with conventional OCT images, simultaneously mapping both the tissue structure and stiffness.

Magnetic Field-Modulated Plasmonic Scattering of Hybrid Nanorods for FFT-Weighted OCT Imaging in NIR-II.

We report a method for fast Fourier transform (FFT)-weighted optical coherence tomography (OCT) in the second biological tissue transparency window by actively modulating the plasmonic scattering of Fe3O4@Au hybrid nanorods using magnetic fields. Instead of tracking the nanoparticles' lateral displacement in conventional magnetomotive OCT imaging, we monitor the nanorod rotation and optical signal changes under an alternating magnetic field in real time. The coherent rotation of the nanorods with the field produces periodic OCT signals, and the FFT is then used to convert the periodic OCT signals in the time domain to a single peak in the frequency domain. This allows automatic screening of nanorod signals from the random biological noises and reconstruction of FFT-weighted images using a computer program based on a time-sequence image set. Compared with conventional magnetomotive OCT, the FFT-weighted imaging technique creates enhanced OCT images with dB-scale contrast over an order of magnitude higher than the original images.

In vitro detection of structural changes in chondrogenic mesenchymal stem cell pellets at the nano-scale using nano-sensitive optical coherance tomography

In vitro detection of structural changes in chondrogenic mesenchymal stem cell pellets at the nano-scale using nano-sensitive optical coherance tomography

Spatio-temporal alterations in retinal and choroidal layers in the progression of age-related macular degeneration (AMD) in optical coherence tomography

Age-related macular degeneration (AMD) is the predominant cause of vision loss in the elderly with a major impact on ageing societies and healthcare systems. A major challenge in AMD management is the difficulty to determine the disease stage, the highly variable progression speed and the risk of conversion to advanced AMD, where irreversible functional loss occurs. In this study we developed an optical coherence tomography (OCT) imaging based spatio-temporal reference frame to characterize the morphologic progression of intermediate age-related macular degeneration (AMD) and to identify distinctive patterns of conversion to the advanced stages macular neovascularization (MNV) and macular atrophy (MA). We included 10,040 OCT volumes of 518 eyes with intermediate AMD acquired according to a standardized protocol in monthly intervals over two years. Two independent masked retina specialists determined the time of conversion to MNV or MA. All scans were aligned to a common reference frame by intra-patient and inter-patient registration. Automated segmentations of retinal layers and the choroid were computed and en-face maps were transformed into the common reference frame. Population maps were constructed in the subgroups converting to MNV (n=135), MA (n=50) and in non-progressors (n=333). Topographically resolved maps of changes were computed and tested for statistical significant differences. The development over time was analysed by a joint model accounting for longitudinal and right-censoring aspect. Significantly enhanced thinning of the outer nuclear layer (ONL) and retinal pigment epithelium (RPE)–photoreceptorinner segment/outer segment (PR-IS/OS) layers within the central 3 mm and a faster thinning speed preceding conversion was documented for MA progressors. Converters to MNV presented an accelerated thinning of the choroid and appearance changes in the choroid prior to MNV onset. The large-scale automated image analysis allowed us to distinctly assess the progression of morphologic changes in intermediate AMD based on conventional OCT imaging. Distinct topographic and temporal patterns allow to prospectively determine eyes with risk of progression and thereby greatly improving early detection, prevention and development of novel therapeutic strategies.

Double diversity optical coherence tomography

ABSTRACT This article provides theoretical analysis for a new generation of optical coherence tomography (OCT) scanners to overcome some main limitations of the technology. In the new design, exposure and detection are not limited to plane-waves that enter or reflect back from the sample exclusively orthogonally. Instead, the sample is scanned by more complex radiation patterns such as spherical or partially spherical light waves. Images that are generated based on this data acquisition strategy can reveal some structural features of the sample that usually remain hidden in conventional OCT imaging. Coherence tomography is based on wide-band reflectometry. Therefore, wavelength diversity is an essential element of technology. The proposed system adds a second form of diversity to the conventional OCT design, which is the angle of incidence for exposure and detection. Since the exposing beam is not necessarily orthogonal to the sample's surface, the propagation wave-vector of the beam has a component in the transverse plane. The amplitude and direction of this transverse component is the second diversity dimension added to the new design. Here, the forward problem is formulated for the most general case, and an efficient image reconstruction algorithm is offered based on the theory of singular value decomposition in continuous space. It is proved mathematically that at the limit, when the amplitude of the transverse component of the wave-vector approaches zero, the formulation of the forward and inverse problems converge to the case of conventional OCT.

False Color Method for Retinal Oximetry

Oximetry is a method for measuring the oxygen saturation of haemoglobin in blood. Particularly, retinal oximetry based in the measurement of oxygen saturation in retinal vessels has acquired great interest to gather information on blood oxygenation from said vessels within inner and outer retina. Non-invasive spectrophotometric retinal oximetry has been studied for over five decades based on imaging spectroscopy. However, Optical Coherence Tomography (OCT) is an alternative to analyze the absorption difference between oxyhaemoglobin (HbO2) and deoxyhaemoglobin (Hb) in the retinal vessels and the choroidal structure. We propose in this paper an alternative process to manipulate conventional OCT images to evaluate changes in the relative haemoglobin oxygen saturation. Conventional OCT images from 570 nm and 600 nm in gray scale are converted to a corresponding color scale to be compared to the oxygenation information involved in the original gray scale OCT images.

Macrophagic enhancement in optical coherence tomography imaging by means of superparamagnetic iron oxide nanoparticles.

The ability of optical coherence tomography (OCT) to visualise macrophages in vivo in coronary arteries is still controversial. We hypothesise that imaging of macrophages in OCT could be enhanced by means of superparamagnetic nanoparticles. We compared the optical backscattering and attenuation of cell pellets containing RAW 264.7 macrophages with those of macrophagic cell pellets labelled with very small superparamagnetic oxydised nanoparticles (VSOP) by means of light intensity analysis in OCT. The labelled macrophages were incubated with VSOP at a concentration of 1 mM Fe, corresponding to intracellular iron concentrations of 8.8 pg/cell. To study the effect of intracellular accumulation on the backscattering, VSOP dilutions without cells were also compared. OCT pullbacks of the PCR tubes containing the cell pellets were obtained and light intensity analysis was performed on raw OCT images in polar view, after normalisation by the backscattering of the PCR tube. The backscattering was estimated by the peak normalised intensity, whilst the attenuation was estimated by the number of pixels between the peak and the normalised intensity 1 (peak-to-one). VSOP-loaded macrophages have higher backscattering than the corresponding unlabelled macrophages (peak normalised intensity 6.30 vs. 3.15) with also slightly higher attenuation (peak-toone 61 vs. 66 pixels). The backscattering of the nanoparticles in suspension was negligible in the light intensity analysis. VSOP increase significantly the optical backscattering of macrophages in the nearinfrared region, with minimal increase in signal attenuation. This finding enables the enhancement of macrophages in conventional OCT imaging with an easily implementable methodology.

Collaborative effects of wavefront shaping and optical clearing agent in optical coherence tomography

We demonstrate that simultaneous application of optical clearing agents (OCAs) and complex wavefront shaping in optical coherence tomography (OCT) can provide significant enhancement of penetration depth and imaging quality. OCA reduces optical inhomogeneity of a highly scattering sample, and the wavefront shaping of illumination light controls multiple scattering, resulting in an enhancement of the penetration depth and signal-to-noise ratio. A tissue phantom study shows that concurrent applications of OCA and wavefront shaping successfully operate in OCT imaging. The penetration depth enhancement is further demonstrated for <italic<ex vivo</italic< mouse ears, revealing hidden structures inaccessible with conventional OCT imaging.

High-resolution contrast-enhanced optical coherence tomography in mice retinae.

Optical coherence tomography (OCT) is a noninvasive interferometric imaging modality providing anatomical information at depths of millimeters and a resolution of micrometers. Conventional OCT images limit our knowledge to anatomical structures alone, without any contrast enhancement. Therefore, here we have, for the first time, optimized an OCT-based contrast-enhanced imaging system for imaging single cells and blood vessels in vivo inside the living mouse retina at subnanomolar sensitivity. We used bioconjugated gold nanorods (GNRs) as exogenous OCT contrast agents. Specifically, we used anti-mouse CD45 coated GNRs to label mouse leukocytes and mPEG-coated GNRs to determine sensitivity of GNR detection in vivo inside mice retinae. We corroborated OCT observations with hyperspectral dark-field microscopy of formalin-fixed histological sections. Our results show that mouse leukocytes that otherwise do not produce OCT contrast can be labeled with GNRs leading to significant OCT intensity equivalent to a 0.5 nM GNR solution. Furthermore, GNRs injected intravenously can be detected inside retinal blood vessels at a sensitivity of ∼0.5 nM, and GNR-labeled cells injected intravenously can be detected inside retinal capillaries by enhanced OCT contrast. We envision the unprecedented resolution and sensitivity of functionalized GNRs coupled with OCT to be adopted for longitudinal studies of retinal disorders.

In vivo deep tissue imaging using wavefront shaping optical coherence tomography.

Multiple light scattering in tissue limits the penetration of optical coherence tomography (OCT) imaging. Here, we present in vivo OCT imaging of a live mouse using wavefront shaping (WS) to enhance the penetration depth. A digital micromirror device was used in a spectral-domain OCT system for complex WS of an incident beam which resulted in the optimal delivery of light energy into deep tissue. Ex vivo imaging of chicken breasts and mouse ear tissues showed enhancements in the strength of the image signals and the penetration depth, and in vivo imaging of the tail of a live mouse provided a multilayered structure inside the tissue.

Application of Extended Field Imaging to Optical Coherence Tomography

Since its invention, optical coherence tomography (OCT) has made remarkable advancements in both image resolution and acquisition speed. 1 Huang D. Swanson E.A. Lin C.P. et al. Optical coherence tomography. Science. 1991; 254: 1178-1181 Crossref PubMed Scopus (12098) Google Scholar , 2 Hangai M. Ojima Y. Gotoh N. et al. Three-dimensional imaging of macular holes with high-speed optical coherence tomography. Ophthalmology. 2007; 114: 763-773 Abstract Full Text Full Text PDF PubMed Scopus (164) Google Scholar With improvements in both hardware and software, higher resolution and less noisy retinal cross-sectional images can be obtained noninvasively. 3 Drexler W. Morgner U. Ghanta R.K. et al. Ultrahigh-resolution ophthalmic optical coherence tomography. Nat Med. 2001; 7: 502-507 Crossref PubMed Scopus (844) Google Scholar Recent improvements to commercially available OCT systems have also included increasing scan length. For example, most spectral-domain OCT machines provide line scans that are approximately 9 mm in length. Therefore, a single scan can include the macula and part of the optic disc. The new DRI OCT-1 (Topcon, Tokyo, Japan), a commercially available, swept-source OCT system, is capable of producing a 12-mm scan that allows the entire optic disc to be imaged with macula. 4 Akagi T. Hangai M. Kimura Y. et al. Peripapillary scleral deformation and retinal nerve fiber damage in high myopia assessed with swept-source optical coherence tomography. Am J Ophthalmol. 2013; 155: 927-936 Abstract Full Text Full Text PDF PubMed Scopus (38) Google Scholar Wide-field OCT imaging is advantageous over conventional OCT imaging because a more comprehensive assessment of the posterior pole can be made with fewer scans. In this study, we examined the use and efficacy of obtaining wide-field OCT images with a novel extended field imaging (EFI) technique. Not only is this technique easy to use, it can be done with readily available items and with existing, unmodified OCT systems.

Peripapillary Rat Sclera Investigated In Vivo With Polarization-Sensitive Optical Coherence Tomography

To demonstrate polarization-sensitive (PS) optical coherence tomography (OCT) for noninvasive, volumetric, and quantitative imaging of the birefringent properties of the peripapillary rat sclera; to compare the findings from PS-OCT images to state-of-the-art histomorphometric analysis of the same tissues. A high-speed PS-OCT prototype operating at 840 nm was modified for imaging the rat eye. Densely sampled PS-OCT raster scans covering an area of ~1.5 × 1.5 mm centered at the papilla were acquired in the eyes of anesthetized male Sprague-Dawley rats. Cross-sectional PS-OCT images were computed, and fundus maps displaying the birefringent properties of the sclera were analyzed. Postmortem histomorphologic analysis was performed. Polarization-sensitive OCT enables visualization of the polarization properties of ocular tissues in vivo. The birefringent characteristics of the rat sclera were quantitatively assessed. Scleral birefringence formed a donut-shaped pattern around the papilla with significantly increased values of 0.703 ± 0.089°/μm (i.e., 1.64 × 10(-3) ± 0.2 × 10(-3); mean ± standard deviation) and 0.721 ± 0.084°/μm (i.e., 1.68 × 10(-3) ± 0.2 × 10(-3)) at an eccentricity of 0.4 mm for the left and right eyes, respectively. Birefringent axis orientation maps revealed a ring-shaped distribution around the optic nerve. Postmortem PS-OCT micrographs provided access to retinal and scleral microstructure and were compared to standard histomorphologic analysis. Polarization-sensitive OCT enables quantitative imaging of tissue polarization properties in addition to conventional OCT imaging based on reflectivity. In the rat sclera, in vivo PS-OCT provides access to volumetric mapping of birefringence. Scleral birefringence is associated with microstructural tissue organization. Therefore, PS-OCT should prove a valuable tool for the in vivo investigation of peripapillary sclera in glaucoma.

Photothermal optical coherence tomography based on the localized surface plasmon resonance of Au nanoring.

The conventional optical coherence tomography (OCT) images based on enhanced scattering and the photothermal (PT) images based on enhanced absorption of the localized surface plasmon (LSP) resonance of Au nanorings (NRIs) in a bio-tissue sample are demonstrated with the scans of an OCT system (1310-nm system), in which the spectral range covers the LSP resonance peak wavelength, and another OCT system (1060-nm system), in which the spectral range is away from the LSP resonance peak wavelength. A PT image is formed by evaluating the modulation frequency (400 Hz) response of an excitation laser with its wavelength (1308 nm) close to the LSP resonance peak at 1305 nm of the Au NRI solution. With the scan of the 1310-nm OCT system, the Au NRI distribution in the bio-tissue sample can be observed in both conventional OCT and PT images. However, with the scan of the 1060-nm OCT system, the Au NRI distribution can be clearly observed only in the PT image. The diffusion process of Au NRIs in the bio-tissue sample can be traced with the scan of either OCT system. Based on phantom experiments, it is shown that the PT image can help in resolving the ambiguity of a conventional OCT image between the enhanced scattering of Au NRIs and the strong scattering of a tissue structure in the 1310-nm OCT scanning. Also, under the condition of weak intrinsic sample scattering, particularly in the scan of the 1060-nm system, the PT signal can be lower than a saturating level, which is determined by the excitation power. By increasing OCT system signal-to-noise ratio or M-mode scan time, the PT signal level can be enhanced.

Morphology of basal cell carcinoma in high definition optical coherence tomography: en‐face and slice imaging mode, and comparison with histology

Optical coherence tomography (OCT) allows real-time, in vivo examination of basal cell carcinoma (BCC). A new high definition OCT with high lateral and axial resolution in a horizontal (en-face) and vertical (slice) imaging mode offers additional information in the diagnosis of BCC and may potentially replace invasive diagnostic biopsies. To define the characteristic morphologic features of BCC by using high definition optical coherence tomography (HD-OCT) compared to conventional histology. A total of 22 BCCs were examined preoperatively by HD-OCT in the en-face and slice imaging mode and characteristic features were evaluated in comparison to the histopathological findings. The following features were found in the en-face mode of HD-OCT: lobulated nodules (20/22), peripheral rimming (17/22), epidermal disarray (21/22), dilated vessels (11/22) and variably refractile stroma (19/22). In the slice imaging mode the following characteristics were found: grey/dark oval structures (18/22), peripheral rimming (13/22), destruction of layering (22/22), dilated vessels (7/22) and peritumoural bright stroma (11/22). In the en-face mode the lobulated structure of the BCC was more distinct than in the slice mode compared to histology. HD-OCT with a horizontal and vertical imaging mode offers additional information in the diagnosis of BCC compared to conventional OCT imaging and enhances the feasibility of non-invasive diagnostics of BCC.

Near Infrared Spectroscopy in Optical Coherence Tomography

Optical coherence tomography (OCT) is a technique that is able to provide cross section views of tissue layers. This fast and non-invasive method is widely used in clinical applications for the diagnosis and treatment of certain diseases. Although conventional OCT is derived from the theory of interferometric imaging, emerging developments, including spectroscopic OCT and related techniques such as dual-band OCT and Raman spectroscopy–OCT, have resulted in significantly improved clinical capabilities for observing the tissue layers through enhanced tissue definition, image resolution, image contrast and scanning speed. This paper reviews the state-of-the-art developments of OCT. It starts with a general introduction of conventional interferometric OCT imaging methods including the time-domain and frequency-domain techniques. The second section explores the advances introduced from spectroscopy techniques in OCT, especially with spectroscopic OCT, dual-band OCT and Raman spectroscopy combined OCT. The final section discusses the current challenges in the application of approaches based on computer-aided diagnosis (CAD) for retinal imaging, for example automated segmentation of tissue layers and tracking disease progression. This task is currently limited by the quality of the recorded data from OCT systems but will be improved by adopting spectroscopic techniques. Finally, we analyse and discuss the improvements that are expected in retinal CAD from the adoption of newly emerging near infrared spectroscopy OCT at multiple wavelengths.

Three-dimensional Imaging of Macular Holes with High-speed Optical Coherence Tomography

To demonstrate the advantages of 3-dimensional imaging of macular hole pathology using new-generation high-speed optical coherence tomography (OCT). Prospective observational case series. Twenty-one eyes from 20 consecutive patients diagnosed with a macular hole. A prototype high-speed OCT system was built based on a Fourier-domain OCT (FD OCT) technology for patient examination. The system has achieved sensitivity of approximately 98 decibels, axial resolution of approximately 4.3 mum in tissue, and an acquisition rate of approximately 18,700 axial scans per second. Three-dimensional imaging of macular hole pathology was performed based on a raster scan protocol consisting of 256x256 axial scans. All patients were imaged with 3-dimensional OCT, Stratus OCT, and OCT Ophthalmoscope C7. Images of macular hole pathologies obtained by 3-dimensional OCT and standard OCT instruments. The 3-dimensional OCT imaging successfully generated realistic 3-dimensional images of the vitreofoveal interface and intraretinal microstructures associated with a macular hole. The 3-dimensional overview of the vitreofoveal interface was helpful in gaining an immediate understanding of the dynamic interactions of the vitreous and fovea. Observations of consecutive en face images in combination with conventional longitudinal images and of cross-sectional images in combination with sectioned volume images enabled identification of intraretinal microstructures and their 3-dimensional extension associated with a macular hole, such as subfoveal structural changes after vitreous traction, connection of the flap to intraretinal structures, the external limiting membrane (ELM) and its disruption, and elevated photoreceptor inner and outer segments delineated by the ELM. The appearance of inner-wall images of a macular hole produced by photoreceptor inner and outer segment backreflection varied throughout macular hole stages. Three-dimensional imaging of macular holes with high-speed OCT based on FD OCT technology offers 3-dimensional overviews that facilitate understanding of the abnormalities in the vitreofoveal interface. It also provides consecutive orthogonal images that allow much more precise and minute observation of 3-dimensionally extending intraretinal structural changes associated with a macular hole than conventional OCT imaging, especially in the photoreceptor inner and outer segments.

Texture analysis of speckle in optical coherence tomography images of tissue phantoms

Optical coherence tomography (OCT) is an imaging modality capable of acquiring cross-sectional images of tissue using back-reflected light. Conventional OCT images have a resolution of 10–15 µm, and are thus best suited for visualizing tissue layers and structures. OCT images of collagen (with and without endothelial cells) have no resolvable features and may appear to simply show an exponential decrease in intensity with depth. However, examination of these images reveals that they display a characteristic repetitive structure due to speckle.The purpose of this study is to evaluate the application of statistical and spectral texture analysis techniques for differentiating living and non-living tissue phantoms containing various sizes and distributions of scatterers based on speckle content in OCT images. Statistically significant differences between texture parameters and excellent classification rates were obtained when comparing various endothelial cell concentrations ranging from 0 cells/ml to 25 million cells/ml. Statistically significant results and excellent classification rates were also obtained using various sizes of microspheres with concentrations ranging from 0 microspheres/ml to 500 million microspheres/ml. This study has shown that texture analysis of OCT images may be capable of differentiating tissue phantoms containing various sizes and distributions of scatterers.