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BACKGROUND: Multi-contrast Jones matrix optical coherence tomography (JM-OCT) can provide quantitative depth-resolved local optical properties by improving the measurement algorithm. MATERIALS AND METHODS: We examined the relationship between depth-resolved local optical properties of eye-corner skin measured by JM-OCT and corresponding wrinkle morphology of aged women (n = 21; age range, 71.7 ± 1.7 years). Wrinkle morphology was analyzed by measuring the surface topography of three-dimensional replicas. The same regions were measured three-dimensionally by JM-OCT, and the local optical properties at each depth were computed. RESULTS: Birefringence (BR) and mean wrinkle depth correlated significantly at a depth of 88.2-138.6 µm from the skin surface, and attenuation coefficient (AC) and mean wrinkle depth correlated significantly at a depth of 12.6-18.9 µm and 189-459.9 µm from the skin surface, although a degree of polarization uniformity (DOPU) did not. Stepwise multiple regression analysis demonstrated that a significant regression equation (R2 = 0.649, P < .001) for predicting mean wrinkle depth was determined by BR at 107.1 µm depth (BR 107.1 µm ), DOPU at 170.1 µm (DOPU 170.1µm ), and AC at 252 µm (AC 252 µm ) as independent variables and that these standardized beta regression coefficients were -0.860, -0.593, and -0.440, respectively, suggesting that BR, DOPU, and AC sufficiently explained mean wrinkle depth. CONCLUSION: These results suggest that BR 107.1 µm , DOPU 170.1 µm, and AC 252 µm may indicate collagen-related structure in the papillary, upper-reticular dermis, and microstructure or tissue density in reticular dermis, respectively, and may be involved in wrinkle formation.
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Envejecimiento de la Piel , Tomografía de Coherencia Óptica , Anciano , Algoritmos , Humanos , Piel/diagnóstico por imagenRESUMEN
Current compression-based optical coherence elastography (OCE) only measures the axial displacement of a tissue, although the tissue also undergoes lateral displacement and microstructural alteration by the compression. In this Letter, we demonstrate a new compression-based OCE method that visualizes not only axial displacement, but also lateral displacement and microstructural decorrelation (MSD). This method employs complex correlation-based displacement and MSD measurements. It is implemented in a swept-source optical coherence tomography system with an active submicrometer compression. The performance of the method was demonstrated by measuring the porcine carotid artery and esophagus. The results showed significant axial and lateral displacements in the tissues by compression. An MSD map demonstrates high-contrast mechanical-property imaging.
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A quantitative signal amplitude estimator for optical coherence tomography (OCT) is presented. It is based on a statistical model of OCT signal and noise, using a Bayesian maximum a posteriori (MAP) estimation framework. Multiple OCT images are used for estimation, similar to the widely utilized intensity averaging method. The estimator is less biased especially at low-intensity regions, where intensity averaging approaches the noise power and hence is biased. The estimator is applied to posterior ocular OCT images and provides high-contrast visualization of pathologies. In addition, histogram analysis objectively shows the superior performance of the estimator compared with intensity averaging.
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Procesamiento de Imagen Asistido por Computador/métodos , Relación Señal-Ruido , Tomografía de Coherencia Óptica , Teorema de BayesRESUMEN
We propose a method to measure the in-plane and out-of-plane displacements of tissue using the correlation coefficients of optical coherence tomography (OCT) signals. The displacements are determined by the local correlation coefficients between digitally shifted reference OCT images and a target image. The method achieves sub-micron displacement measurement with an accuracy better than 0.32 µm and repeatability better than 0.36 µm. The feasibility of the method was examined by measuring the displacement field of a laser irradiated porcine retina. This method successfully visualized the dynamic change of the displacement field during laser irradiation.
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Procesamiento de Imagen Asistido por Computador/métodos , Tomografía de Coherencia Óptica/métodos , Animales , Ojo/citología , Fantasmas de Imagen , PorcinosRESUMEN
BACKGROUND: To describe Doppler optical coherence tomography (OCT) imaging of ruptured retinal arterial macroaneurysms (RAMs). METHODS: Four eyes of four patients with ruptured RAMs were prospectively studied. Vascular imaging was obtained using swept-source Doppler OCT, and compared with indocyanine green angiography images. RESULTS: En face projection of Doppler OCT images clearly showed RAMs at the corresponding locations of lesions in the indocyanine green angiography images. In Doppler OCT images, RAMs were located in the inner retina in three eyes and in the medium layer of the retina in one eye. In one eye, detection of RAMs by standard OCT was difficult because of the presence of inner retinal hemorrhage. In one eye, disappearance of blood flow after direct laser photocoagulation could be confirmed by Doppler OCT images. CONCLUSIONS: Doppler OCT imaging may potentially function as a noninvasive complementary procedure with indocyanine green angiography.
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Aneurisma Roto/diagnóstico , Efecto Doppler , Arteria Retiniana/patología , Hemorragia Retiniana/diagnóstico , Tomografía de Coherencia Óptica , Anciano , Anciano de 80 o más Años , Aneurisma Roto/cirugía , Colorantes , Femenino , Angiografía con Fluoresceína , Humanos , Imagenología Tridimensional , Verde de Indocianina , Coagulación con Láser , Masculino , Estudios Prospectivos , Hemorragia Retiniana/cirugíaRESUMEN
Noise statistics of phase-resolved optical coherence tomography (OCT) imaging are complicated and involve noises of OCT, correlation of signals, and speckles. In this paper, the statistical properties of phase shift between two OCT signals that contain additive random noises and speckle noises are presented. Experimental results obtained with a scattering tissue phantom are in good agreement with theoretical predictions. The performances of the dual-beam method and conventional single-beam method are compared. As expected, phase shift noise in the case of the dual-beam-scan method is less than that for the single-beam method when the transversal sampling step is large.
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This paper presents the theory and numerical implementation of a maximum likelihood estimator for local phase retardation (i.e., birefringence) measured using Jones-matrix-based polarization sensitive optical coherence tomography. Previous studies have shown conventional mean estimations of phase retardation and birefringence are significantly biased in the presence of system noise. Our estimator design is based on a Bayes' rule that relates the distributions of the measured birefringence under a particular true birefringence and the true birefringence under a particular measured birefringence. We used a Monte-Carlo method to calculate the likelihood function that describes the relationship between the distributions and numerically implement the estimator. Our numerical and experimental results show that the proposed estimator was asymptotically unbiased even with low signal-to-noise ratio and/or for the true phase retardations close to the edge of the measurement range. The estimator revealed detailed clinical features when applied to the in vivo anterior human eye.
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Algoritmos , Teorema de Bayes , Interpretación de Imagen Asistida por Computador/métodos , Tomografía de Coherencia Óptica/métodos , Birrefringencia , Humanos , Funciones de Verosimilitud , Relación Señal-RuidoRESUMEN
A new metric representing polarization uniformity is presented. Noise corrected degree of polarization uniformity (DOPU) is computed from polarization-sensitive optical coherence tomography (OCT), and selectively visualizes tissue with the multiple scattering, such as highly pigmented tissues. The new metric is designed to be minimally sensitive to systematic additive noise. The performance of this new metric is analyzed by numerical simulation and in vivo human retinal imaging, using Jones matrix OCT. The new metric exhibited only a small dependency on the signal-to-noise ratio. Selective in vivo visualization of pigmented tissues in the human retina is demonstrated, with cross sectional and en-face images.
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Relación Señal-Ruido , Tomografía de Coherencia Óptica/métodos , Humanos , Procesamiento de Imagen Asistido por Computador , Pigmentos Biológicos/metabolismo , Retina/metabolismoRESUMEN
We demonstrate a method that reduces the noise caused by multi-scattering (MS) photons in an in vivo optical coherence tomography image. This method combines a specially designed image acquisition (i.e., optical coherence tomography scan) scheme and subsequent complex signal processing. For the acquisition, multiple cross-sectional images (frames) are sequentially acquired while the depth position of the focus is altered for each frame by an electrically tunable lens. In the signal processing, the frames are numerically defocus-corrected, and complex averaged. Because of the inconsistency in the MS-photon trajectories among the different electrically tunable lens-induced defocus, this averaging reduces the MS signal. Unlike the previously demonstrated volume-wise multi-focus averaging method, our approach requires the sample to remain stable for only a brief period, approximately 70 ms, thus making it compatible with in vivo imaging. This method was validated using a scattering phantom and in vivo unanesthetized small fish samples, and was found to reduce MS noise even for unanesthetized in vivo measurement.
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We demonstrate a deep-learning-based scatterer density estimator (SDE) that processes local speckle patterns of optical coherence tomography (OCT) images and estimates the scatterer density behind each speckle pattern. The SDE is trained using large quantities of numerically simulated OCT images and their associated scatterer densities. The numerical simulation uses a noise model that incorporates the spatial properties of three types of noise, i.e., shot noise, relative-intensity noise, and non-optical noise. The SDE's performance was evaluated numerically and experimentally using two types of scattering phantom and in vitro tumor spheroids. The results confirmed that the SDE estimates scatterer densities accurately. The estimation accuracy improved significantly when compared with our previous deep-learning-based SDE, which was trained using numerical speckle patterns generated from a noise model that did not account for the spatial properties of noise.
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RATIONALE: Autosomal recessive bestrophinopathy (ARB) is a subtype of bestrophinopathy caused by biallelic mutations of the BEST1 gene, which affect the retinal pigment epithelium (RPE). Studying RPE abnormalities through imaging is essential for understanding ARB. This case series involved the use of multimodal imaging techniques, namely autofluorescence (AF) imaging at 488 nm [short-wavelength AF] and 785 nm [near-infrared AF (NIR-AF)] and polarization-sensitive optical coherence tomography (PS-OCT), to investigate RPE changes in 2 siblings with ARB. PATIENT CONCERNS: Two Japanese siblings (Case 1: male, followed for 20-23 years; Case 2: female, followed for 13-17 years) carried compound heterozygous mutations of the BEST1 gene. DIAGNOSIS: Both siblings were diagnosed with ARB. INTERVENTIONS AND OUTCOMES: Multimodal imaging techniques were used to evaluate RPE changes. Both siblings had funduscopic changes similar to those seen in the vitelliruptive stage of Best vitelliform macular dystrophy during the follow-up period. NIR-AF imaging showed hypo-AF of the entire macular lesion in both cases, and this hypo-AF remained stable over time. PS-OCT confirmed reduced RPE melanin content in these hypo-AF areas. Additionally, hyper-NIR-AF dots were observed within hypo-NIR-AF areas. Concomitant identification of focally thickened RPE melanin on PS-OCT imaging and hyper-AF on short-wavelength AF imaging at the sites containing hyper-NIR-AF dots indicated that the hyper-NIR-AF dots had originated from either stacked RPE cells or RPE dysmorphia. LESSONS: We confirmed RPE abnormalities in ARB, including diffuse RPE melanin damage in the macula alongside evidence of RPE activity-related changes. This case series demonstrates that multimodal imaging, particularly NIR-AF and PS-OCT, provides detailed insights into RPE alterations in ARB.
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Bestrofinas , Enfermedades Hereditarias del Ojo , Imagen Multimodal , Enfermedades de la Retina , Epitelio Pigmentado de la Retina , Tomografía de Coherencia Óptica , Humanos , Imagen Multimodal/métodos , Masculino , Femenino , Tomografía de Coherencia Óptica/métodos , Enfermedades Hereditarias del Ojo/genética , Enfermedades Hereditarias del Ojo/diagnóstico por imagen , Enfermedades de la Retina/genética , Enfermedades de la Retina/diagnóstico por imagen , Epitelio Pigmentado de la Retina/diagnóstico por imagen , Epitelio Pigmentado de la Retina/patología , Bestrofinas/genética , Adulto Joven , Imagen Óptica/métodos , Adolescente , HermanosRESUMEN
Polarization-sensitive optical coherence tomography (PS-OCT) is a promising biomedical imaging tool for the differentiation of various tissue properties. However, the presence of multiple-scattering (MS) signals can degrade the quantitative polarization measurement accuracy. We demonstrate a method to reduce MS signals and increase the measurement accuracy of Jones matrix PS-OCT. This method suppresses MS signals by averaging multiple Jones matrix volumes measured using different focal positions. The MS signals are decorrelated among the volumes by focus position modulation and are thus reduced by averaging. However, the single scattering signals are kept consistent among the focus-modulated volumes by computational refocusing. We validated the proposed method using a scattering phantom and a postmortem medaka fish. The results showed reduced artifacts in birefringence and degree-of-polarization uniformity measurements, particularly in deeper regions in the samples. This method offers a practical solution to mitigate MS-induced artifacts in PS-OCT imaging and improves quantitative polarization measurement accuracy.
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We demonstrate label-free dynamic optical coherence tomography (D-OCT)-based visualization and quantitative assessment of patterns of tumor spheroid response to three anti-cancer drugs. The study involved treating human breast adenocarcinoma (MCF-7 cell-line) with paclitaxel (PTX), tamoxifen citrate (TAM), and doxorubicin (DOX) at concentrations of 0 (control), 0.1, 1, and 10 µM for 1, 3, and 6 days. In addition, fluorescence microscopy imaging was performed for reference. The D-OCT imaging was performed using a custom-built OCT device. Two algorithms, namely logarithmic intensity variance (LIV) and late OCT correlation decay speed (OCDS[Formula: see text]) were used to visualize the tissue dynamics. The spheroids treated with 0.1 and 1 µM TAM appeared similar to the control spheroid, whereas those treated with 10 µM TAM had significant structural corruption and decreasing LIV and OCDS[Formula: see text] over treatment time. The spheroids treated with PTX had decreasing volumes and decrease of LIV and OCDS[Formula: see text] signals over time at most PTX concentrations. The spheroids treated with DOX had decreasing and increasing volumes over time at DOX concentrations of 1 and 10 µM, respectively. Meanwhile, the LIV and OCDS[Formula: see text] signals decreased over treatment time at all DOX concentrations. The D-OCT, particularly OCDS[Formula: see text], patterns were consistent with the fluorescence microscopic patterns. The diversity in the structural and D-OCT results among the drug types and among the concentrations are explained by the mechanisms of the drugs. The presented results suggest that D-OCT is useful for evaluating the difference in the tumor spheroid response to different drugs and it can be a useful tool for anti-cancer drug testing.
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Antineoplásicos , Neoplasias de la Mama , Humanos , Femenino , Tomografía de Coherencia Óptica/métodos , Esferoides Celulares , Antineoplásicos/farmacología , Antineoplásicos/uso terapéutico , Neoplasias de la Mama/diagnóstico por imagen , Neoplasias de la Mama/tratamiento farmacológico , Doxorrubicina/farmacología , Doxorrubicina/uso terapéutico , Paclitaxel/farmacología , Paclitaxel/uso terapéuticoRESUMEN
We demonstrate deep-learning neural network (NN)-based dynamic optical coherence tomography (DOCT), which generates high-quality logarithmic-intensity-variance (LIV) DOCT images from only four OCT frames. The NN model is trained for tumor spheroid samples using a customized loss function: the weighted mean absolute error. This loss function enables highly accurate LIV image generation. The fidelity of the generated LIV images to the ground truth LIV images generated using 32 OCT frames is examined via subjective image observation and statistical analysis of image-based metrics. Fast volumetric DOCT imaging with an acquisition time of 6.55 s/volume is demonstrated using this NN-based method.
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[This corrects the article on p. 168 in vol. 13, PMID: 35154862.].
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An automated choroidal vessel segmentation and quantification method for high-penetration optical coherence tomography (OCT) was developed for advanced visualization and evaluation of the choroidal vasculature. This method uses scattering OCT volumes for the segmentation of choroidal vessels by using a multi-scale adaptive threshold. The segmented choroidal vessels are then processed by multi-scale morphological analysis to quantify the vessel diameters. The three-dimensional structure and the diameter distribution of the choroidal vasculature were then obtained. The usefulness of the method was then evaluated by analyzing the OCT volumes of normal subjects.
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Automatización , Coroides/anatomía & histología , Coroides/irrigación sanguínea , Procesamiento de Imagen Asistido por Computador , Tomografía de Coherencia Óptica/métodos , Algoritmos , Angiografía , Coroides/diagnóstico por imagen , Humanos , Verde de Indocianina/metabolismoRESUMEN
An advanced version of Jones matrix optical coherence tomography (JMT) is demonstrated for Doppler and polarization sensitive imaging of the posterior eye. JMT is capable of providing localized flow tomography by Doppler detection and investigating the birefringence property of tissue through a three-dimensional (3-D) Jones matrix measurement. Owing to an incident polarization multiplexing scheme based on passive optical components, this system is stable, safe in a clinical environment, and cost effective. Since the properties of this version of JMT provide intrinsic compensation for system imperfection, the system is easy to calibrate. Compared with the previous version of JMT, this advanced JMT achieves a sufficiently long depth measurement range for clinical cases of posterior eye disease. Furthermore, a fine spectral shift compensation method based on the cross-correlation of calibration signals was devised for stabilizing the phase of OCT, which enables a high sensitivity Doppler OCT measurement. In addition, a new theory of JMT which integrates the Jones matrix measurement, Doppler measurement, and scattering measurement is presented. This theory enables a sensitivity-enhanced scattering OCT and high-sensitivity Doppler OCT. These new features enable the application of this system to clinical cases. A healthy subject and a geographic atrophy patient were measured in vivo, and simultaneous imaging of choroidal vasculature and birefringence structures are demonstrated.
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Efecto Doppler , Tomografía de Coherencia Óptica/métodos , Anciano , Análisis de Fourier , Fondo de Ojo , Atrofia Geográfica/patología , Humanos , Mácula Lútea/patología , Masculino , Disco Óptico/patologíaRESUMEN
Spectral-domain optical coherence tomography (SD-OCT) is an interferometric optical tomography technique and provides high resolution and noninvasive visualization of retinal morphology. The purpose of this study was to assess the utility of thickness maps and quantitative thickness measurements of the ganglion cell complex (GCC: retinal nerve fiber layer, ganglion cell layer, and inner plexiform layer) obtained by SD-OCT of a mouse model of N-methyl-d-aspartate (NMDA)-induced retinal damage. SD-OCT imaging was performed in ddY mice at 1, 3, and 7 days and 1 month after intravitreal injection of NMDA. GCC thickness maps and circle cross-sectional OCT images were made from volumetric OCT images. The GCC thickness was measured on a cross-sectional OCT image on a circle with a radius 300 µm from the center of the optic nerve disc. Histological analysis was conducted by measuring the GCC thickness at the same time intervals. The thickness maps and the quantitative thickness values of GCC showed thickness changes at each time point in the NMDA-treated mice when compared with normal and vehicle-treated mice. Both the OCT sectional images and the histological images revealed increases in GCC thickness at 1 day, followed by decreases from 3 days to 1 month after NMDA injection. The GCC thickness measured using OCT sectional images correlated with the thickness measured using histological images. In conclusion, GCC thickness mapping is a useful method for evaluating NMDA-induced retinal degeneration in mice.
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Agonistas de Aminoácidos Excitadores/toxicidad , N-Metilaspartato/toxicidad , Retina/efectos de los fármacos , Degeneración Retiniana/patología , Células Ganglionares de la Retina/patología , Tomografía de Coherencia Óptica/métodos , Animales , Tamaño de la Célula , Masculino , Ratones , Disco Óptico/patología , Degeneración Retiniana/inducido químicamenteRESUMEN
PURPOSE: To study the choroidal thickness profile using high-penetration optical coherence tomography in central serous chorioretinopathy (CSC). METHODS: Thirty-five eyes of 27 subjects with CSC and 35 healthy, age-matched control eyes were included. We observed the choroid using the prototype high-penetration optical coherence tomography. Fluorescein angiography and indocyanine green angiography were performed to identify the CSC location and activity. The choroidal thicknesses was measured manually in various conditions or locations, and the choroidal thickness maps were obtained from cube scans and calculating software and composed of nine sectors in the Early Diabetic Retinopathy Study chart. RESULTS: The subfoveal choroidal thicknesses in all eyes with CSC were significantly (P < 0.01) greater than that in the control eyes. The choroidal thickness at the fovea and the fluorescein points of leakage were significantly (P < 0.01 for both comparisons) greater in eyes with CSC than the corresponding locations in the fellow eyes in patients with unilateral disease. Dilatation of the choroidal large vessels was significantly (P < 0.01) more common in CSC. The foveal choroidal thickness was significantly greater in eyes with venous dilatation (P < 0.01) than those without. The mean choroidal thickness was significantly (P < 0.05) greater in all sectors of the Early Diabetic Retinopathy Study chart except for the inner (P = 0.087) and outer (P = 0.053) inferior sectors. The percent mean choroidal thicknesses compared with the normal controls in the nasal sector were significantly (P < 0.05 and P < 0.01, respectively) greater in the inner and outer circles than in the superior, temporal, and inferior sectors. CONCLUSION: The choroid is diffusely thickened in CSC likely because of the choroidal vascular dilatation. The nasal macula undergoes the greatest alterations in choroidal thickness compared with the other areas.
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Coriorretinopatía Serosa Central/complicaciones , Coroides/patología , Coriorretinopatía Serosa Central/diagnóstico , Colorantes , Femenino , Angiografía con Fluoresceína , Humanos , Verde de Indocianina , Presión Intraocular/fisiología , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Tomografía de Coherencia Óptica , Agudeza Visual/fisiologíaRESUMEN
We propose a single-step method appropriated for a fiber-optic probe-based full-range spectral domain optical coherence tomography (OCT). The fiber-optic probe was scanned over a sample with a magnetically driven actuator. In the reference arm, a phase shift of π/2 was applied during two neighbor axial scanning, from which the complex spectral interferogram was directly reconstructed. Since the complex-conjugate-free OCT image is obtained by doing just one Fourier transform on the complex interferogram, obtaining the full-range image is simple in algorithm and effective in computation time. Some full-range images of biological samples created with the proposed method are presented and the processing time is analyzed.