Optical Coherence Tomography Data Research Articles

Short-term results with faricimab in neovascular age-related macular degeneration resistant to both ranibizumab and aflibercept

PurposeSome patients with neovascular age-related macular degeneration (nAMD) do not respond to anti-VEGF treatment or develop tolerance or tachyphylaxis. If optimal treatment response is lacking with a given drug, switching to another is a common practice. The aim of this study was to report short-term outcomes of treatment switch to faricimab in real-world patients with nAMD resistant to both aflibercept and ranibizumab. DesignSingle-center, retrospective real-world cohort study. MethodsChart-review of 13 eyes of 13 multi-switch patients using electronic injection database, electronic medical records, and optical coherence tomography (OCT) data from May–September 2023. ResultsFaricimab treatment led to absence of fluid (subretinal, or both subretinal and intraretinal fluid) in 31% of the eyes and a reduction of fluid in 77% of the eyes at 4 weeks following the switch. The best-corrected visual acuity did not change significantly. No ocular or systemic safety events were observed. ConclusionsSwitching to faricimab seems a reasonable option in patients with nAMD who were previously resistant to both aflibercept and ranibizumab treatment. We noted a high rate of morphological response and improvement in anatomical parameters, with nearly one-third of the patients achieving dry macula after just one injection. No change in BCVA was seen. No safety issues were noted. The durability of these results warrants additional investigations. Trial registrationClinicalTrials.gov, registration number: NCT06231121, date of registration: 21/01/2024, retrospectively registered.

Probabilistic volumetric speckle suppression in OCT using deep learning.

We present a deep learning framework for volumetric speckle reduction in optical coherence tomography (OCT) based on a conditional generative adversarial network (cGAN) that leverages the volumetric nature of OCT data. In order to utilize the volumetric nature of OCT data, our network takes partial OCT volumes as input, resulting in artifact-free despeckled volumes that exhibit excellent speckle reduction and resolution preservation in all three dimensions. Furthermore, we address the ongoing challenge of generating ground truth data for supervised speckle suppression deep learning frameworks by using volumetric non-local means despeckling-TNode- to generate training data. We show that, while TNode processing is computationally demanding, it serves as a convenient, accessible gold-standard source for training data; our cGAN replicates efficient suppression of speckle while preserving tissue structures with dimensions approaching the system resolution of non-local means despeckling while being two orders of magnitude faster than TNode. We demonstrate fast, effective, and high-quality despeckling of the proposed network in different tissue types that are not part of the training. This was achieved with training data composed of just three OCT volumes and demonstrated in three different OCT systems. The open-source nature of our work facilitates re-training and deployment in any OCT system with an all-software implementation, working around the challenge of generating high-quality, speckle-free training data.

The effect of silicone oil on the anatomical and functional parameters of the retina during surgery of regmatogenic retinal detachment

Vitrectomy followed by endotamponade of the vitreal cavity with silicone oil (SO) is one of the main techniques of treating severe forms of regmatogenic retinal detachment (RRD). Endotamponade with SO, having numerous advantages and a huge potential, carries the risk of a number of complications arising at various times of application. The literature review analyzes the published data on the effect of tamponade SO on the retina and the function of central vision in RRD surgery: visual acuity, indicators of light and color sensitivity, data of electrophysiological test results. Possible causes of deteriorated central vision functions directly or indirectly related to tamponade with SO are discussed: changes in the thickness and structure of the retina or its individual layers as shown by optical coherence tomography (OCT) data, microcirculation disorders according to OCT angiography, fluorescein angiography, Doppler laser scanning, as well as pathohistological findings related to SO migration into the fundus of eye tissues.

Computationally efficient adaptive optimization of vector-method parameters for phase-sensitive strain estimation in optical coherence elastography

A new method for automatic adaptive optimization of strain estimation in phase-sensitive optical coherence tomography (OCT) is introduced. More specifically, this paper focuses on optimizing the estimation of strain using the vector method, in which OCT signals are treated as vectors in the complex plane. In phase-sensitive optical coherence elastography, the tissue strain is extracted from the interframe phase variation between the complex-valued scans acquired for the initial and deformed tissue. This phase variation is proportional to interframe displacements of scatterers and corresponds to the argument of the pixel-by-pixel product of the initial OCT scan and complex-conjugate deformed scan. Measurement noises and the so-called ‘speckle noise’ that are intrinsic to OCT scans cause degradation of the derived scan obtained by such multiplication. To mitigate the noise influence, complex-valued pixel amplitudes in the derived scan are usually averaged over a certain window. The interframe strain is found by estimating the gradient of the interframe phase difference. The noise influence on the strain estimation can also be reduced by increasing the scale over which the phase-variation gradient is estimated. However, choosing a too large window for preliminary averaging may significantly distort the reconstructed strain distribution. Similarly, a too large scale for gradient estimation may also cause errors in the estimated-strain magnitude and even its sign (because of possible phase wrapping). Therefore, appropriately performed adaptive choice of the strain-estimation parameters can greatly improve the quality of strain estimation. Here, we present a unified approach for adaptive choice of both the averaging-window size and gradient-estimation scale that were initially considered separately. The new method is computationally simplified but enables approximately the same strain-estimation quality, as demonstrated using both simulated and experimental OCT data.

A Practical Framework for the Integration of Structural Data Into Perimetric Examinations.

We sought to develop and evaluate a practical framework that supports structurally enhanced perimetric examinations. Two perimetric strategies were compared: standard Zippy Estimation through Sequential Testing (ZEST) procedure, a traditional visual field test with population-based prior distributions, and structural-ZEST (S-ZEST), enhanced with individual optical coherence tomography data to determine the starting parameters. The integration and collection of data was facilitated by a bespoke application developed in Shiny R (R Studio). The test was implemented using the Open Perimetry Interface on the Compass perimeter (CentreVue-iCare, Italy). The strategies were evaluated via simulations and on 10 visually healthy participants. The usability of the application was assessed in a simulated environment with 10 test users. In simulations, the S-ZEST improved test speed in patients with glaucoma. In the practical implementation, there was a statistically significant decrease in the testing time (approximately 26%) and in the number of presentations per test with S-ZEST (P < 0.001). The structure-function relationship was similar between the two strategies. The time taken for users to complete the sequence of actions on the application was 52.9 ± 11.5 seconds (mean ± standard deviation). Structurally enhanced perimetric examination can significantly improve test time in healthy subjects and can be delivered through a user-friendly interface. Further testing will need to assess feasibility and performance of S-ZEST in patients with glaucoma. We have developed a user-friendly web application based within the Shiny environment for R, which implements an automated extraction of optical coherence tomography data from raw files and performs real-time calculations of structural features to inform the perimetric strategy.

Approved AI-based fluid monitoring to identify morphological and functional treatment outcomes in neovascular age-related macular degeneration in real-world routine

AimTo predict antivascular endothelial growth factor (VEGF) treatment requirements, visual acuity and morphological outcomes in neovascular age-related macular degeneration (nAMD) using fluid quantification by artificial intelligence (AI) in a real-world...

Simulation of coronary fractional flow reserve and whole-cycle flow based on optical coherence tomography in individual patients with coronary artery disease

Computer simulations of coronary fractional flow reserve (FFR) based on coronary imaging have emerged as an attractive alternative to invasive measurements. However, most methods are proprietary and employ non-physiological assumptions. Our aims were to develop and validate a physiologically realistic open-source simulation model for coronary flow, and to use this model to predict FFR based on intracoronary optical coherence tomography (OCT) data in individual patients. We included patients undergoing elective coronary angiography with angiographic borderline coronary stenosis. Invasive measurements of coronary hyperemic pressure and absolute flow and OCT imaging were performed. A computer model of coronary flow incorporating pulsatile flow and the effect of left ventricular contraction was developed and calibrated, and patient-specific flow simulation was performed. Forty-eight coronary arteries from 41 patients were included in the analysis. Average FFR was 0.79 ± 0.14, and 50% had FFR ≤ 0.80. Correlation between simulated and measured FFR was high (r = 0.83, p < 0.001). Average difference between simulated FFR and observed FFR in individual patients was − 0.009 ± 0.076. Overall diagnostic accuracy for simulated FFR ≤ 0.80 in predicting observed FFR ≤ 0.80 was 0.88 (0.75–0.95) with sensitivity 0.79 (0.58–0.93) and specificity 0.96 (0.79–1.00). The positive predictive value was 0.95 (0.75–1.00) and the negative predictive value was 0.82 (0.63–0.94). In conclusion, realistic simulations of whole-cycle coronary flow can be produced based on intracoronary OCT data with a new, computationally simple simulation model. Simulated FFR had moderate numerical agreement with observed FFR and a good diagnostic accuracy for predicting hemodynamic significance of coronary stenoses.

Прогностические критерии функциональных исходов хирургического лечения идиопатического эпиретинального фиброза, основанные на оптической когерентной томографии

Abstrakt Prognostic criteria of epiretinal membrane surgery functional outcomes, based on optical coherencetomography A.A. Shpak, A.S. Zhuravlev, S.V. Kolesnik, A.I. Kolesnik, F.A. Avakyan, E.A. Shikhalieva S. Fyodorov Eye Microsurgery Federal State Institution, Moscow, Russian Federation Relevance. Surgery for epiretinal fibrosis is currently a routineprocedure in vitreoretinal surgery. However, in some cases, the functionalresults of the surgery are unsatisfactory. With the widespread introductionof optical coherence tomography (OCT) into clinical practice, manyprognostic criteria for the functional outcomes of surgery for thispathology have been proposed, the description of which is the purposeof this review. Purpose. To describe prognostic criteria of idiopathicepiretinal fibrosis surgery functional outcomes based on opticalcoherence tomography data. Material and methods. To perform thisreview, clinical studies were searched through the eLibrary, PubMed, andScopus database, using the keywords «epiretinal fibrosis», «prognosticcriteria», «optical coherence tomography» (in the eLibrary database),«prognostic criteria», «epiretinal membrane» and «optical coherencetomography» (in the PubMed and Scopus databases). A total of 39 articlesrelevant to the topic of the review were selected. Results. A large numberof OCT criteria have been proposed to predict functional outcomes ofepiretinal membrane surgery, some of which remain understudied. Conclusion. Сone outer segment tips and ellipsoid zone appear to be the most informative and easy-to-use prognostic criteria. Further studiesare needed to determine the best set of prognostic parameters. Key words: optical coherence tomography, epiretinal fibrosis, epiretinalmembrane, classification, prognostic criteria

Microstructural changes in the retina in children with retinopathy of prematurity according to optical coherence tomography. Literature review

Retinopathy of prematurity (ROP) is a crucial problem in modern ophthalmology. ROP is a vasoproliferative disease of the eyes in premature infants. Approximately 50,000 children worldwide have become blind because of ROP. The determining indicator in the development of visual acuity is the morphofunctional state of the macula, structural changes of which can lead to disturbances in its functions and, consequently, decreased vision. The present review analyzed available OCT (optical coherence tomography) data on the morphometric and structural state of the retina in children with ROP. Morphometric features of the macular zone in children in the scar period of ROP can be presented by an increase in retinal thickness in the center of the fovea and changes in the profile of the macula by smoothness or absence of foveal depression. These are more pronounced in children after laser coagulation of the retina in the active phase of ROP and in very premature babies. In some cases with increased retinal thickness in the center of the fovea, the presence of internal layers and an increase in the thickness of the outer nuclear layer are noted. Structural features of the macula with favorable outcomes of RP can be expressed by traction displacement of the foveola, photoreceptor layer thinning and pigment epithelium unevenness, intra and epiretinal fibrosis, choriocapillaris layer atrophy, discontinuity of the connection of the outer and internal segments of the photoreceptors and the pigment epithelium–choriocapillaris complex, and central retinoschisis. Furthermore, this review presents mixed results from studies on the impact of structural changes in the macula in cicatricial ROP on visual function.

Разработка программы для персонализированного подхода в лечении субретинальных кровоизлияний

Abctract Software development for a personalized approach in the treatment of subretinal hemorrhages R.R. Fayzrakhmanov, E.D. Вosov, V.A. Bogdanova, I.I. Tumanov, G.O. Karpov N.I. Pirogov National Medical Surgical Center, Moscow, Russian Federation Institute of Advanced Training of Physicians N.I. Pirogov National Medical Surgical Center, Moscow, Russian Federation Design Bureau «Rus’», Moscow, Russian Federation Purpose. Development and clinical application of software for individual calculation of the volume of fibrinolytic infusion solution for surgical treatment of submacular hemorrhages. Material and methods. Based on the processing of optical coherence tomography data using threedimensional visualization, the program 3D volume calculator was developed. As a vitreoretinal intervention, a two-port 27G surgery was performed with controlled subretinal administration of a calculated recombinant prourokinase solution through a 38G cannula and hexafluoroethane tamponade at 20% of the volume of the vitreal cavity. Results. Developed software makes it possible to measure the volume of submacular hemorrhage, and also calculates an individualized amount of subretinal infusion solution for reliable displacement of the blood clot to the periphery. 2 weeks after surgery for submacular hemorrhage, complete dislocation was observed in 40 cases (93%). Conclusion. Сurrently, minimally invasive surgery and a personalized approach are the fundamental directions in modern ophthalmology. Application of the proposed software in clinical practice has proven its effectiveness in relation to morphological and functional perspectives in the treatment of submacular hemorrhages. Key words: submacular hemorrhage, software, calculation of fibrinolytic volume, minimally invasive surgery

Influencing Factors on Pupillary Light Responses as a Biomarker for Local Retinal Function in a Large Normative Cohort.

Investigating influencing factors on the pupillary light response (PLR) as a biomarker for local retinal function by providing epidemiological data of a large normative collective and to establish a normative database for the evaluation of chromatic pupil campimetry (CPC). Demographic and ophthalmologic characteristics were captured and PLR parameters of 150 healthy participants (94 women) aged 18 to 79 years (median = 46 years) were measured with L-cone- and rod-favoring CPC protocols. Linear-mixed effects models were performed to determine factors influencing the PLR and optical coherence tomography (OCT) data were correlated with the pupillary function volume. Relative maximal constriction amplitude (relMCA) and latency under L-cone- and rod-favoring stimulation were statistically significantly affected by the stimulus eccentricity (P < 0.0001, respectively). Iris color and gender did not affect relMCA or latency significantly; visual hemifield, season, and daytime showed only minor influence under few stimulus conditions. Age had a statistically significant effect on latency under rod-specific stimulation with a latency prolongation ≥60 years. Under photopic and scotopic conditions, baseline pupil diameter declined significantly with increasing age (P < 0.0001, respectively). Pupillary function volume and OCT data were not correlated relevantly. Stimulus eccentricity had the most relevant impact on relMCA and latency of the PLR during L-cone- and rod-favoring stimulation. Latency is prolonged ≥60 years under scotopic conditions. Considering the large study collective, a representative normative database for relMCA and latency as valid readout parameters for L-cone- and rod-favoring stimulation could be established. This further validates the usability of the PLR in CPC as a biomarker for local retinal function.

Assessing the efficacy of 2D and 3D CNN algorithms in OCT-based glaucoma detection

Glaucoma is a progressive neurodegenerative disease characterized by the gradual degeneration of retinal ganglion cells, leading to irreversible blindness worldwide. Therefore, timely and accurate diagnosis of glaucoma is crucial, enabling early intervention and facilitating effective disease management to mitigate further vision deterioration. The advent of optical coherence tomography (OCT) has marked a transformative era in ophthalmology, offering detailed visualization of the macula and optic nerve head (ONH) regions. In recent years, both 2D and 3D convolutional neural network (CNN) algorithms have been applied to OCT image analysis. While 2D CNNs rely on post-prediction aggregation of all B-scans within OCT volumes, 3D CNNs allow for direct glaucoma prediction from the OCT data. However, in the absence of extensively pre-trained 3D models, the comparative efficacy of 2D and 3D-CNN algorithms in detecting glaucoma from volumetric OCT images remains unclear. Therefore, this study explores the efficacy of glaucoma detection through volumetric OCT images using select state-of-the-art (SOTA) 2D-CNN models, 3D adaptations of these 2D-CNN models with specific weight transfer techniques, and a custom 5-layer 3D-CNN-Encoder algorithm. The performance across two distinct datasets is evaluated, each focusing on the macula and the ONH, to provide a comprehensive understanding of the models’ capabilities in identifying glaucoma. Our findings demonstrate that the 2D-CNN algorithm consistently provided robust results compared to their 3D counterparts tested in this study for glaucoma detection, achieving AUC values of 0.960 and 0.943 for the macular and ONH OCT test images, respectively. Given the scarcity of pre-trained 3D models trained on extensive datasets, this comparative analysis underscores the overall utility of 2D and 3D-CNN algorithms in advancing glaucoma diagnostic systems in ophthalmology and highlights the potential of 2D algorithms for volumetric OCT image-based glaucoma detection.

Evaluation of optical coherence tomography findings in patients with multiple sclerosis and glaucoma.

Glaucoma and multiple sclerosis (MS) can cause optic disc pathology and, in this way, affect optical coherence tomography (OCT) data. In this context, the objective of this study is to investigate the changes in the mean, quadrant, and sector data measured by OCT in glaucoma and MS patients. The sample of this prospective cohort study consisted of 42 MS patients (84 eyes), 34 Primary open-angle glaucomas patients (67 eyes), and 24 healthy control subjects (48 eyes). The MS group was divided into two groups according to the presence of a history of optic neuritis. Accordingly, those with a history of optic neuritis were included in the MS ON group, and those without a history of optic neuritis were included in the MS NON group. The differences between these groups in the mean, quadrant, and sector data related to the retinal nerve fiber layer (RNFL) and ganglion cell complex (GCC) were evaluated. Superior nasal (SN), superior temporal (ST), inferior nasal (IN), and superior quadrant (SUP) values were significantly lower in the glaucoma group than in the MS group (p < 0.05). The mean superior GCC (GCC SUP) value was significantly lower in the MS ON group than in the glaucoma group (p < 0.05). On the other hand, SN, ST, inferior temporal (IT), IN, average RNFL (AVE RNFL), semi-average superior RNFL (SUP AVE RNFL), semi-average inferior RNFL (INF AVE RNFL), SUP, and inferior quadrant RNFL (INF) values were significantly lower in the glaucoma group than in the MS NON group (p < 0.05). RNFL and GCC parameters get thinner in MS and glaucoma patients. While the inferior and superior RNFL quadrants are more frequently affected in glaucoma patients, the affected quadrants vary according to the presence of a history of optic neuritis in MS patients. It is noteworthy that the GCC superior quadrant was thin in MS ON patients. The findings of this study indicate that OCT data may be valuable in the differential diagnosis of glaucoma and MS.

Total variation regularized tensor ring decomposition for OCT image denoising and super-resolution

This paper suggests a novel hybrid tensor-ring (TR) decomposition and first-order tensor-based total variation (FOTTV) model, known as the TRFOTTV model, for super-resolution and noise suppression of optical coherence tomography (OCT) images. OCT imaging faces two fundamental problems undermining correct OCT-based diagnosis: significant noise levels and low sampling rates to speed up the capturing process. Inspired by the effectiveness of TR decomposition in analyzing complicated data structures, we suggest the TRFOTTV model for noise suppression and super-resolution of OCT images. Initially, we extract the nonlocal 3D patches from OCT data and group them to create a third-order low-rank tensor. Subsequently, using TR decomposition, we extract the correlations among all modes of the grouped OCT tensor. Finally, FOTTV is integrated into the TR model to enhance spatial smoothness in OCT images and conserve layer structures more effectively. The proximal alternating minimization and alternative direction method of multipliers are applied to solve the obtained optimization problem. The effectiveness of the suggested method is verified by four OCT datasets, demonstrating superior visual and numerical outcomes compared to state-of-the-art procedures.

Plaque Ruptures Are Related to High Plaque Stress and Strain Conditions: Direct Verification by Using In Vivo OCT Rupture Data and FSI Models.

While it has been hypothesized that high plaque stress and strain may be related to plaque rupture, its direct verification using in vivo coronary plaque rupture data and full 3-dimensional fluid-structure interaction models is lacking in the current literature due to difficulty in obtaining in vivo plaque rupture imaging data from patients with acute coronary syndrome. This case-control study aims to use high-resolution optical coherence tomography-verified in vivo plaque rupture data and 3-dimensional fluid-structure interaction models to seek direct evidence for the high plaque stress/strain hypothesis. In vivo coronary plaque optical coherence tomography data (5 ruptured plaques, 5 no-rupture plaques) were acquired from patients using a protocol approved by the local institutional review board with informed consent obtained. The ruptured caps were reconstructed to their prerupture morphology using neighboring plaque cap and vessel geometries. Optical coherence tomography-based 3-dimensional fluid-structure interaction models were constructed to obtain plaque stress, strain, and flow shear stress data for comparative analysis. The rank-sum test in the nonparametric test was used for statistical analysis. Our results showed that the average maximum cap stress and strain values of ruptured plaques were 142% (457.70 versus 189.22 kPa; P=0.0278) and 48% (0.2267 versus 0.1527 kPa; P=0.0476) higher than that for no-rupture plaques, respectively. The mean values of maximum flow shear stresses for ruptured and no-rupture plaques were 145.02 dyn/cm2 and 81.92 dyn/cm2 (P=0.1111), respectively. However, the flow shear stress difference was not statistically significant. This preliminary case-control study showed that the ruptured plaque group had higher mean maximum stress and strain values. Due to our small study size, larger scale studies are needed to further validate our findings.

A non-invasive capacitive sensor to investigate the Leidenfrost phenomenon: a proof of concept study

A volatile sessile liquid droplet or a sublimating solid manifests levitation on its own vapor when placed on a sufficiently heated surface, illustrating the Leidenfrost phenomenon. In this study, we introduce a non-invasive capacitance method for investigating this phenomenon, offering a potentially simpler alternative to existing optical techniques. The designed sensor features in-plane miniaturized electrodes forming a double-comb structure, also known as an interdigitated capacitor. Initially, the sensor’s capacitance is characterized for various distances between the sensor and a dielectric material. The influence of the sensor substrate material and the spacing between the electrodes on the sensor’s capacitance is also investigated. To demonstrate the feasibility of the method, a sublimating dry ice pellet is placed on the capacitive sensor, and its performance is evaluated. We present results for the dimensionless vapor layer thickness and the pellet’s lifetime at different substrate temperatures, derived from the capacitance output. The results are compared with Optical Coherence Tomography (OCT) data, serving as a benchmark. While the temporal evolution of the sensor’s output, variation in the dimensionless vapor layer thickness, and the lifetime of the dry ice pellet align with expected results from OCT, notable quantitative deviations are observed. These deviations are attributed to practical experimental limitations rather than shortcoming in the sensor’s working principle. Although this necessitates further investigation, the methodology presented in this paper can potentially serve as an alternative for the detection and measurement of Leidenfrost vapor layers.

Unveiling Key Pathological Indicators for Disease Progression in Vogt Koyanagi Harada Disease and Sympathetic Ophthalmia Through Advanced Choroidal Volume Analysis

ABSTRACT Purpose To evaluate the association between quantitative parameters derived from volume analysis of optical coherence tomography (OCT) data and disease worsening in Vogt-Koyanagi-Harada disease (VKHD) and sympathetic ophthalmia (SO). Methods This retrospective study, conducted at Osaka University Hospital, employed swept-source OCT scans from patients diagnosed with VKHD or SO between October 2012 and January 2021. The choroidal vessel structure was segmented and visualized in three dimensions, generating quantitative vessel volume maps. Region-specific choroidal vessel volume (CVV), choroidal volume (CV), and vessel index (VI) were scrutinized for their potential correlation with disease severity. Results Thirty-five eyes of 18 VKHD and 2 SO patient (8 females, 10 males) were evaluated. OCT-derived CVV maps revealed regional CV alterations in VKHD and SO patients. Two parameters, i.e. CV at 3- and 6-month follow-ups (p = 0.044, p = 0.040, respectively, with area under the ROC curve of 0.70) and CVV at 6 months (p = 0.046, area under the ROC curve of 0.71), were significantly higher in recurrent VKHD and SO compared to effectively treated cases. Conclusions The volume analysis of OCT images facilitates a three-dimensional visualization of choroidal alterations, which may serve as a reflection of disease severity in VKHD and SO patients. Furthermore, noninvasive initial CVV or CV measurements may serve as potential biomarkers for predicting disease recurrence in VKHD and SO.

K-Space Approach in Optical Coherence Tomography: Rigorous Digital Transformation of Arbitrary-Shape Beams, Aberration Elimination and Super-Refocusing beyond Conventional Phase Correction Procedures.

For the most popular method of scan formation in Optical Coherence Tomography (OCT) based on plane-parallel scanning of the illuminating beam, we present a compact but rigorous K-space description in which the spectral representation is used to describe both the axial and lateral structure of the illuminating/received OCT signals. Along with the majority of descriptions of OCT-image formation, the discussed approach relies on the basic principle of OCT operation, in which ballistic backscattering of the illuminating light is assumed. This single-scattering assumption is the main limitation, whereas in other aspects, the presented approach is rather general. In particular, it is applicable to arbitrary beam shapes without the need for paraxial approximation or the assumption of Gaussian beams. The main result of this study is the use of the proposed K-space description to analytically derive a filtering function that allows one to digitally transform the initial 3D set of complex-valued OCT data into a desired (target) dataset of a rather general form. An essential feature of the proposed filtering procedures is the utilization of both phase and amplitude transformations, unlike conventionally discussed phase-only transformations. To illustrate the efficiency and generality of the proposed filtering function, the latter is applied to the mutual transformation of non-Gaussian beams and to the digital elimination of arbitrary aberrations at the illuminating/receiving aperture. As another example, in addition to the conventionally discussed digital refocusing enabling depth-independent lateral resolution the same as in the physical focus, we use the derived filtering function to perform digital "super-refocusing." The latter does not yet overcome the diffraction limit but readily enables lateral resolution several times better than in the initial physical focus.

Ultrawidefield Fluorescein Angiography and OCT Findings in Children and Young Adults with Autosomal Dominant Neovascular Inflammatory Vitreoretinopathy

PurposeAutosomal dominant neovascular inflammatory vitreoretinopathy (ADNIV) is a rare genetic (CAPN5) autoimmune condition typically diagnosed in adulthood and characterized by a triad of inflammation, retinal degeneration and neovascularization. We report novel multimodal imaging findings in children and young adults with ADNIV and early treatment response to short-duration local and/or systemic corticosteroids. DesignRetrospective consecutive case series. ParticipantsTen patients under the age of 25 with ADNIV and available multimodal imaging. MethodsThe medical records of patients under the age of 25 with a diagnosis of ADNIV with ultra-widefield fluorescein angiography (UWFFA) and optical coherence tomography (OCT) data were reviewed. Main Outcome MeasuresUWFFA and OCT findings at baseline and following local corticosteroids. ResultsMedian age at presentation was 14 years (range 9-24 years). OCT on presentation demonstrated CME in 8/20 eyes and symptomatic vitreoretinal interface disease in 2/20 eyes. Initial UWFFA demonstrated retinal vascular leakage (20/20 eyes, 100%), peripheral non-perfusion (13/20 eyes, 65%), and retinal neovascularization (6/20 eyes, 30%). Retinal vascular leakage improved with local corticosteroids and neovascularization regressed with anti-VEGF therapy. ConclusionsUWFFA findings of prefibrotic ADNIV reported in adults were also present in children and young adults. Early testing for a pathogenic CAPN5 variant in at-risk children and regularly scheduled screening for uveitis and retinal vasculitis with UWFFA and OCT may prompt earlier intervention. Short duration local steroids are effective at treating retinal vascular leakage and macular edema but are not durable suggesting a potential role for steroid-sparing immunosuppressive therapy. Early treatment may alter the natural history of disease.

Impact of residual stress on coronary plaque stress/strain calculations using optical coherence tomography image-based multi-layer models.

Mechanical stress and strain conditions play an important role in atherosclerosis plaque progression, remodeling and potential rupture and may be used in plaque vulnerability assessment for better clinical diagnosis and treatment decisions. Single layer plaque models without residual stress have been widely used due to unavailability of multi-layer image segmentation method and residual stress data. However, vessel layered structure and residual stress have large impact on stress/strain calculations and should be included in the models. In this study, intravascular optical coherence tomography (OCT) data of coronary plaques from 10 patients were acquired and segmented to obtain the three-layer vessel structure using an in-house automatic segmentation algorithm. Multi- and single-layer 3D thin-slice biomechanical plaque models with and without residual stress were constructed to assess the impact of residual stress on stress/strain calculations. Our results showed that residual stress led to a more uniform stress distribution across the vessel wall, with considerable plaque stress/strain decrease on inner wall and increase on vessel out-wall. Multi-layer model with residual stress inclusion reduced inner wall maximum and mean plaque stresses by 38.57% and 59.70%, and increased out-wall maximum and mean plaque stresses by 572.84% and 432.03%. These findings demonstrated the importance of multi-layer modeling with residual stress for more accurate plaque stress/strain calculations, which will have great impact in plaque cap stress calculation and plaque rupture risk assessment. Further large-scale studies are needed to validate our findings.