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Optical coherence tomography angiography analysis of changes in the retina and the choroid after haemodialysis
摘要： The purpose of this study is to evaluate the effect of haemodialysis on perfused vessel density, choroidal thickness (CT), and retinal thickness in end-stage renal disease (ESRD) using swept-source optical coherence tomography angiography (SS-OCTA). We studied twenty-nine eyes of 29 ESRD patients by ophthalmologic examination and SS-OCTA before and after haemodialysis. The colour-coded perfusion density maps were generated and perfused vessel density was calculated. Changes in systemic and other ocular parameters such as retinal and choroidal thickness were measured and analysed. Total perfused vessel density decreased significantly after haemodialysis in the choriocapillaris; it was not significantly different in the superficial capillary plexus (SCP) and the deep capillary plexus (DCP). Total CT decreased significantly, but total retinal thickness was not significantly different. There was no significant correlation between choriocapillaris perfused vessel density and CT. The reduction in choriocapillaris perfused vessel density correlated with the decrease in systolic and mean arterial blood pressures. The decrease in CT correlated with the ultrafiltration volume. There were no significant systemic and ocular factors affecting change in retinal thickness and perfused vessel density of SCP and DCP. This is the first study to assess the effect of haemodialysis on blood flow changes using SS-OCTA; changes may be more prominent in the choroidal compared to the retinal layer.
关键词： angiography,choroidal thickness,haemodialysis,Optical coherence tomography,end-stage renal disease,perfused vessel density,retinal thickness
更新于2025-09-10 09:29:36
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Morphometrical evaluation of the choriocapillaris imaged by swept-source optical coherence tomography angiography
摘要： Purpose: To assess the reproducibility of quantitative morphometrical evaluation of the choriocapillaris imaged with swept-source optical coherence tomography angiography (SS-OCTA). Subjects and methods: This observational, cross-sectional case series included 35 eyes of healthy individuals and 32 eyes of 32 patients. Two images of the fovea were taken using SS-OCTA with 3×3 mm squares. Images of the choriocapillaris within 800×800 pixel squares centered at the fovea were analyzed morphometrically using open-source software “AngioTool” that applies a Gaussian recursive filter and multiscale Hessian enhancement. This program’s vessel thickness and intensity parameters can be changed to aid vessel detection. We measured the pairs of images per eye with different parameter sets and calculated the intraclass correlation (ICC) for the morphometrical results. After determining the parameters that produced high reproducibility, we evaluated regional variations in 800×800 pixel mm squares within the fovea. Results: The ICCs for vessel area, total vessel length, vessel diameter index, and mean lacunarity were over 0.9 using the parameters of “vessel thickness” 3–4 and intensity 15 in the group including all subjects. When measurements were performed using these same parameter values, the vessel density and mean vessel diameter index were 60.5% and 19.1±0.389, respectively. Vessel density, vessel length, vessel diameter index, and mean lacunarity did not change significantly within an 800×800 pixel square centered at the fovea except for the 200×200 pixel square at the foveal center. Conclusion: SS-OCTA images of the choriocapillaris can be measured with high reproducibility by morphometrical evaluation using open-source software with multiscale Hessian enhancement. Such automated morphometric analysis can provide an objective evaluation of the choriocapillaris.
关键词： choriocapillaris,swept-source optical coherence tomography angiography,morphometry,vessel density
更新于2025-09-10 09:29:36
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Evaluation of graft anastomosis using time–intensity curves and quantitative near-infrared fluorescence angiography during peripheral arterial bypass grafting
摘要： Near-infrared fluorescence angiography (NIR) visualizes blood perfusion using the fluorescence property of indocyanine green (ICG). This study aimed to retrospectively determine the usefulness of a quantitative analysis using NIR to predict the patency of peripheral arterial bypass grafts by measuring their fluorescence luminance intensities (FLIs). Thirteen grafts in 11 patients who underwent peripheral arterial bypass grafting were divided into a patent graft group (n = 7) and a failed graft group (n = 6). The changes in the FLIs of ICG opacification through the graft and distal host artery were retrospectively analyzed using stored NIR data. The time–intensity curves (TICs) of ICG opacification through the graft (Qgraft) and distal host artery (Qdistal) were measured. Two parameters, Δ(Qgraft ? Qdistal) and integral(Qgraft ? Qdistal), were also analyzed. Although not significant, decreases in Qgraft were observed in the failed graft groups. The Qdistal of the failed graft group was significantly attenuated as compared with that of the patent graft group. Δ(Qgraft ? Qdistal) increased only in the failed graft group, which indicates widening of the gap in FLI. Integral(Qgraft ? Qdistal) was higher in the failed graft group, as it reflects the accumulation of ICG opacification. The TICs were influenced by anastomotic stenosis in the distal site of the host arteries. Our results indicate that the comparison of Δ(Qgraft ? Qdistal) and integral (Qgraft ? Qdistal) quantitatively analyzed using NIR can potentially predict anastomotic stenosis.
关键词： Indocyanine green,Near-infrared fluorescence angiography,Peripheral arterial bypass graft
更新于2025-09-10 09:29:36
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New Interpretation of Multimodality Fundus Imaging for Retinal Cavernous Hemangioma
摘要： Objective: The aim of this study was to investigate the multimodality imaging features of retinal cavernous hemangiomas (RCHs). Materials and Methods: The clinical data of three patients with RCH were reviewed and the imaging findings were analyzed. Results: The color photographs of the fundus showed bead-like vesicles in the retina. Some vesicles showed plasma erythrocyte separation—with plasma on the top and erythrocytes at the bottom—which was consistently detected as high spontaneous fluorescence on fundus fluorescence angiography. Other vesicles were surrounded by thick walls and fibrous tissue, showing high spontaneous fluorescence, although they did not show any changes on fluorescence angiography. Optical coherence tomography (OCT) could not discriminate the different characteristics of the vesicles, but could clearly discriminate the appearance of the vesicles and their location on the retina, as well as other structural features. Conclusions: Fundus color photography, fundus fluorescein angiography, and OCT can aid in acquiring a better understanding of the structural features of cavernous hemangioma and its relationship with retinal vessels.
关键词： fluorescein angiography,fundus color photography,Fundus autofluorescence,Retinal cavernous hemangioma,OCT
更新于2025-09-10 09:29:36
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Optical coherence tomography angiography (OCTA) flow speed mapping technology for retinal diseases
摘要： Introduction: Optical coherence tomography angiography (OCTA) is a noninvasive imaging modality for depth-resolved visualization of retinal vasculature. Angiographic data couples with structural data to generate a cube scan, from which en-face images of vasculature can be obtained at various axial positions. OCTA has expanded understanding of retinal vascular disorders and has primarily been used for qualitative analysis. Areas covered: Recent studies have explored the quantitative properties of OCTA, which would allow for objective assessment and follow-up of retinal pathologies. Various quantitative metrics have been developed, such as foveal avascular zone area and vessel density. However, quantitative assessment of the characteristics of retinal blood flow remains limited, as OCTA provides an image depicting either the presence or absence of flow at a particular region without information of relative velocities. The development of variable interscan time analysis (VISTA) overcomes this limitation. The VISTA algorithm generates a color-coded map of relative blood flow speeds. VISTA has already demonstrated utility in furthering our understanding of various retinal pathologies, such as geographic atrophy, choroidal neovascularization, aneurysmal type 1 neovascularization, and diabetic retinopathy. Expert commentary: VISTA, an OCTA flow speed mapping technique, may have a role in developing the utility of OCTA as a screening tool.
关键词： flow speed mapping,diabetic retinopathy,age-related macular degeneration,VISTA,quantitative OCTA,OCTA,Optical coherence tomography angiography,variable interscan time analysis,OCT
更新于2025-09-10 09:29:36
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Special issue – Non-invasive vascular imaging
摘要： This special issue focusses on advances in non-invasive vascular imaging with some outstanding articles on cutting-edge imaging technologies and their clinical use. For many years, invasive catheter angiography with its attendant risks was the only method to obtain more detailed information on the vasculature than plain radiographs could provide, although only the outline of the lumen is visualised directly. Indeed, the risks of invasive angiography are such that they have had to be factored into risk assessment prior to embarking on imaging investigation. For example, the landmark NASCET trial of carotid endarterectomy was reported in terms of the number needed to both investigate and treat to provide bene?t in the secondary prevention of stroke since the investigation itself (invasive carotid arteriography) as well as the proposed surgical intervention could both cause precisely the morbidity/mortality that the strategy was intending to avoid, i.e., stroke. As such, a shift to non-invasive carotid imaging in this scenario if equally accurate would mean a lower number to treat for the same bene?t as the potential morbidity/mortality simply associated with investigation had been negated.
关键词： Non-invasive vascular imaging,angiography,CT,ultrasound,MRI
更新于2025-09-10 09:29:36
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Optical coherence tomography angiography in exudative age-related macular degeneration: a predictive model for treatment decisions
摘要： Aims To evaluate on optical coherence tomography angiography (OCT-A), the predictive role of different qualitative findings of choroidal neovascularisations (CNV) in assessing the status of exudative age-related macular degeneration (eAMD) and to develop a potential model to predict the CNV activity. Methods Retrospective review of the multimodal imaging records of patients with eAMD obtained during treatment for type 1 or type 2 CNV. The qualitative analysis of CNVs on OCT angiograms assessed the presence or absence of tiny branching vessels, loops, peripheral anastomotic arcades and choriocapillaris hypointense halo. These findings were then correlated with those of structural OCT scans. A score forecast was built and validated. results One hundred and twenty-six eAMD eyes were enrolled in the study. Exudation was observed in 90 eyes (71%) on structural OCT. The qualitative OCT-A analysis revealed: tiny branching vessels in 82.5% of the cases, vascular loops in 81.7%, peripheral anastomotic arcades in 66.7% and choriocapillaris hypointense halo in 54.8%. In the univariate analysis, each OCT-A parameter showed a statistically significant correlation with exudation on structural OCT (p<0.001). The overall analysis demonstrated a sensitivity of 96.7% and a positive predictive value of 87.9%. In the multivariate analysis, a model with four criteria predicted an exudative lesion in 97.6% of cases and one with two criteria (tiny branching vessels and peripheral anastomotic arcades) in 71.2%. Conclusions The presence of tiny branching vessels and a peripheral anastomotic arcade appears to predict the lesion activity with a good accuracy and the model based on four criteria enables optimal decisions regarding retreatment in eAMD.
关键词： exudative age-related macular degeneration,optical coherence tomography angiography,treatment decisions,choroidal neovascularisations,predictive model
更新于2025-09-10 09:29:36
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Improving visualization and quantitative assessment of choriocapillaris with swept source OCTA through registration and averaging applicable to clinical systems
摘要： Choriocapillaris (CC) visualization and quantification remains challenging. We propose an innovative three-step registration and averaging approach using repeated swept source optical coherence tomography angiography (SS-OCTA) scans to conduct automatic quantitative assessment on CC. Six subjects were enrolled, each imaged at several locations with SS-OCTA from macular to equatorial regions using 3 mm × 3 mm scanning pattern. Five repeated volumes were collected for each subject. The complex optical microangiography (OMAG) algorithm was applied to identify blood flow in CC slab. An automatic three-step registration of translation, affine and B-Spline was applied to en face OCTA images of CC, followed with averaging. A fuzzy clustering approach was used to segment vasculature and flow deficits from the averaged images. The improvement in visualization of CC was evaluated and the average intercapillary distance was estimated by calculating the averaged capillary lumen spacing. A series of quantitative indices of flow deficit density, number, size, complexity index and aspect ratio index (FDD, FDN, FDS, FDCI and FDARI) were designed and validated with the increase of repeated scan numbers for averaging. Quantitative assessment was applied and compared on CC in macular and equatorial regions. The intercapillary distance was observed to be around 24 μm at macula and increased toward equatorial regions. All five quantitative indices (FDD, FDN, FDS, FDCI and FDARI) showed significant changes with multiple averaging and tend to become stable with repeated number of 4. Our proposed registration and averaging algorithm significantly improved the visualization of CC with SS-OCTA. The designed five indices for CC provide more options in the quantitative assessment of CC and are of great potentials in assisting the understanding of disease pathology, early diagnosis and treatment monitoring.
关键词： quantitative assessment,optical coherence tomography angiography,choriocapillaris,averaging,registration
更新于2025-09-10 09:29:36
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Different Filling Patterns of the Choriocapillaris in Fluorescein and Indocyanine Green Angiography in Primate Eyes Under Elevated Intraocular Pressure
摘要： To investigate the hemodynamics of the choriocapillaris in primate eyes under elevated intraocular pressure. Indocyanine green angiography (ICGA) and fluorescein angiography (FA) were performed in two monkeys after elevation of the intraocular pressure (IOP) to 35 and 60 mm Hg. ICGA and FA showed no perfusion delays in the choriocapillaris at 35 mm Hg. The slow dye filling at 60 mm Hg made it possible to observe the early phase angiography sequence. During ICGA, C-shaped precapillary arterioles multiplied in numbers and emerged in the posterior pole, forming the outer rim of the numerous mosaics or lobules. Dye subsequently infiltrated into the lobules. During FA, after numerous hyperfluorescent spots emerged in the posterior pole, each of the spots enlarged and became numerous mosaics with a dark outer rim. When the FA and ICGA images were superimposed, the C-shaped arterioles observed during the ICGA were shown to correspond to the outer dark rim of the mosaics seen during the FA. The earliest dye emergence was delayed during FA compared to ICGA, with 13 seconds elapsing in monkey 1 and 4 seconds in monkey 2. The horizontal diameter of the optic disc contained three to four mosaics in both monkeys. The choriocapillaris lobules appear to be supplied from peripheral arterioles, not central. After blood perfuses the lobules, it drains into the venules at the center. Mosaic or lobular patterns during FA may reflect extravasated fluorescein from the fenestrated choriocapillaris.
关键词： central venule theory,angiography,choriocapillaris
更新于2025-09-10 09:29:36
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Comparison of Neovascular Lesion Area Measurements From Different Swept-Source OCT Angiographic Scan Patterns in Age-Related Macular Degeneration
摘要： PURPOSE. We compared area measurements for the same neovascular lesions imaged using swept source optical coherence tomography angiography (SS-OCTA) and enlarging scan patterns. METHODS. Patients with neovascular age-related macular degeneration were imaged using a 100-kHz SS-OCTA instrument (PLEX Elite 9000). The scanning protocols included the 3 3 3, 6 3 6, 9 3 9, and 12 3 12 mm ?elds of view. Two groups were studied. Group 1 included small lesions contained within the 3 3 3 mm scan, and Group 2 included larger lesions that were fully contained within the 6 3 6 mm scan. RESULTS. A total of 30 eyes of 26 patients were enrolled in Group 1 and 30 eyes of 25 patients were enrolled in Group 2. In Group 1, the automated mean lesion area measurements were 1.11 (SD ? 0.78), 1.14 (SD ? 0.80), and 1.27 (SD ? 0.82) mm2 for the 3 3 3, 6 3 6, and 12 3 12 mm scans, respectively (ANOVA P < 0.001; post hoc comparisons, P ? 0.184, 3 3 3 vs. 6 3 6 mm; P < 0.001 for the other two pairs). In Group 2, the automated mean lesion area measurements were 5.43 (SD ? 2.56), 5.53 (SD ? 2.48), and 5.49 (SD ? 2.65) mm2 for the 6 3 6, 9 3 9, and 12 3 12 mm scans, respectively (ANOVA P ? 0.435; post-hoc comparisons, P ? 0.062, 6 3 6 vs. 9 3 9 mm; P ? 0.553, 6 3 6 vs. 12 3 12 mm; P ? 0.654, 9 3 9 vs. 12 3 12 mm). CONCLUSIONS. The similarity in lesion area measurements across different scan patterns suggests that SS-OCTA imaging can be used to follow quantitatively the enlargement of choroidal neovascularization as the disease progresses.
关键词： neovascular AMD,optical coherence tomography angiography,swept-source OCTA,quantified measurement comparison,choroidal neovascularization
更新于2025-09-10 09:29:36