Areas Of Nonperfusion Research Articles

Macular Perfusion Deficits on OCT Angiography Correlate with Nonperfusion on Ultrawide-field Fluorescein Angiography in Diabetic Retinopathy

To evaluate the correlation between nonperfusion parameters on OCT angiography (OCTA) and ultrawide-field fluorescein angiography (UWF-FA) in subjects with diabetes mellitus (DM). Prospective, cross-sectional study. Subjects with DM and a wide range of diabetic retinopathy (DR) severity seen at a tertiary referral center. We used averaged 3× 3 mm OCTA scans to measure geometric perfusion deficit (GPD), vessel density, and vessel length density in the full retina, superficial capillary plexuses (SCPs), and deep capillary plexuses (DCPs). Nonperfusion was manually delineated on UWF-FA to quantify central, peripheral, and total retinal nonperfusion (mm2 and % area). Correlation between OCTA parameters and UWF-FA nonperfusion, and accuracy of these OCTA and UWF-FA parameters in detecting clinically referable eyes, using receiver operating characteristic (ROC) curve analysis, sensitivity, specificity, and area under the ROC curve (AUC). The study included 67 eyes (12 eyes with no signs of DR, 8 mild, 22 moderate, 14 severe nonproliferative DR, and 11 treatment-naive proliferative DR). There was a fair-to-moderate correlation between either central or total retinal nonperfusion on UWF-FA (mm2) and GPD in the SCP (r= 0.482 and r= 0.464, respectively) and DCP (r= 0.470 and r= 0.456, respectively). Receiver operating characteristic analysis showed the DCP GPD significantly superior to other OCTA parameters at the DCP with the largest overall AUC on OCTA for distinguishing referable DR (0.905). Furthermore, the GPD parameter had the largest AUC in each respective capillary layer compared with other parameters. Overall, the total UWF-FA nonperfusion area showed a comparable AUC (0.907) and performed significantly better than peripheral nonperfusion (P= 0.041). Comparing the AUC values between GPD and UWF-FA nonperfusion parameters showed no significant difference in discerning referable DR. Nonperfusion as quantified on OCTA (3× 3 mm) correlated with UWF-FA parameters and both were comparable in detecting referable DR. These macular OCTA metrics, particularly DCP GPD, have the potential for gauging the overall ischemic status of the retina, with an important clinical role in identifying eyes with clinically referable DR. Proprietary or commercial disclosure may be found after the references.

Особенности и закономерности течения фотоиндуцированного тромбоза ретинальных вен в эксперименте

Central retinal vein occlusion (CRVO) was first described in the 19th century, but some aspects of the pathogenesis of the disease remain controversial to this day [1]. In the development of retinal vein obturation hemorheological, coagulation, hemodynamic and immune-inflammatory factors are important [2, 3]. Creation of an experimental model of CRVO and its branches (BRVO) as close as possible to the natural course of the disease, will provide new knowledge about the pathogenesis of retinal vein obturation, which may help in the development of a new method for treating this pathology. Purpose. To study patterns of the course of photoinduced retinal vein occlusion in an in vivo experiment. Materials and methods. The experiment was carried out on 40 rabbits, which reproduced photoinduced CRVO and BRVO by introducing «Photoditazine» and laser irradiation of the retinal vessels of the right eye. The left eye of the animals remained intact and constituted the comparison group. On days 1, 3, 7, and 14 after the intervention, ophthalmoscopy, optical coherence tomography of the retina was performed, and 10 rabbits were taken out of the experiment, followed by enucleation, hematoxylin-eosin staining, and light microscopy of the structures of the posterior segment of the eyeball. Fluorescein angiography retinal vessels was performed on days 3 and 7 after modeling thrombosis of the retinal vein. Statistical processing of the obtained results was carried out using the IBM SPSS Statistics 27 program. Differences were considered statistically significant at p < 0.05. Results. With experimental photoinduced CRVO and BRVO, a mixed thrombus is formed in the vessel, occupying more than half of the retinal vein diameter, which causes an increase in the time of venous perfusion by 2.0 times (p = 0.047) compared with the intact eyes of rabbits, as well as pronounced microcirculation disorders, leading to the development of cystic macular edema and the appearance of non-perfused areas of the retina. Conclusions. An experimental study of photoinduced thrombosis of the retinal veins confirmed the feasibility of early treatment before the occurrence of complications of occlusion of the CRVO and BRVO, since changes in chorioretinal structures and hemodynamic disturbances in the retinal vessels microvasculature appear as early as 1-3 days after the formation of a thrombus in the retinal vessel lumen. Keywords: experimental model, central retinal vein occlusion, branch retinal vein occlusion, pathogenesis, microcirculation

En-face widefield optical coherence tomography angiography for understanding vascular networks changes in two cases of acute retinal necrosis

PurposeThe present study assesses the utility of en-face widefield optical coherence tomography angiography (OCTA) imaging for evaluating the retinal vascular network during the course of treatment in acute retinal necrosis(ARN).ObservationsOCTA images of two cases of acute retinal necrosis were analyzed. Case 1 was a 15-year-old male with visual crowding in his right eye who had best-corrected visual acuity of 16/20 and intraocular pressure of 25 mmHg in his right eye on initial evaluation. Case 2 was a 57-year-old male with visual crowding in his left eye who had best-corrected visual acuity of 20/20 in his left eye on initial examination and intraocular pressure of 19.3 mmHg.In both patients, dynamic changes could be tracked by en-face ultra-widefield OCTA imaging before and up to 1 year after surgical treatment. The images showed arteriovenous anastomosis and the nonperfused area on the surface of the retina.Conclusions and importanceEn-face widefield OCTA is useful for monitoring the structure of retinal vessels over time in acute retinal necrosis. Wide-angle OCTA is used to non-invasively examine retinal vascular dynamic changes in ARN. OCTA artifacts due to intraocular inflammation appeared, making interpretation difficult. These will remain as issues in the future. It seems difficult for a while to completely replace FA due to the problem of image clarity.

Retinal neovascularization as self-organized criticality on ultra-widefield fluorescein angiography imaging of diabetic retinopathy.

Do the distributions of surface area of non-perfusion (NP) and neovascularization (NV) on ultra-widefield fluorescein angiography (UWF FA) in patients with diabetic retinopathy (DR) differ significantly? Inclusion criteria were patients who had a UWF FA taken for DR at the Kellogg Eye Center from January 2009 to May 2018. Exclusion criteria included previous panretinal photocoagulation and significant media opacity (e.g., vitreous haemorrhage or significant cataract). UWF FAs were manually segmented for surface areas of NP and NV. The total areas per patient were organized in a histogram, and logarithmically binned to test against power law and exponential distributions. Then, a computational model was constructed in Python 3.7 to suggest a mechanistic explanation for the observed distributions. Analysis of areas of NV across 189 images demonstrated a superior fit by the least squares method to a power law distribution (p = 0.014) with an R2 fit of 0.9672. Areas of NP over 794 images demonstrated a superior fit with an exponential distribution instead (p = 0.011). When the far periphery was excluded, the R2 fit for the exponential distribution was 0.9618. A computational model following the principles of self-organized criticality (SOC), akin to earthquake and forest fire models, matched these datasets. These distributions inform what useful statistics may be applied to study of these imaging characteristics. Further, the difference in event distribution between NV and NP suggests that the two phenomena are mechanistically distinct. NV may follow SOC, propagating as a catastrophic event in an unpredictable manner.

Ultra-Wide-Field Fluorescein Angiography Assessment of Non-Perfusion in Patients with Diabetic Retinopathy Treated with Anti-Vascular Endothelial Growth Factor Therapy

Purpose: To follow the evolution of peripheral ischemia by fluorescein angiography (FA) on ultra-wide-field (UWF) images in diabetic patients treated with anti-vascular endothelial growth factor (anti-VEGF) for macular edema. Methods: Prospective, non-interventional cohort study analyzing UWF-FA images of 48 patients with diabetic retinopathy (48 eyes) treated for diabetic macular edema. UWF-FA was performed at baseline and after one year of anti-VEGF therapy (M12). The primary endpoint was the change in the non-perfusion index. Results: Of the 48 patients included in this study, 25 completed the one-year follow-up, and 20 had FA images of sufficient quality to be interpreted. The non-perfusion index did not significantly change from baseline after one year of anti-VEGF treatment (0.7% of the non-perfused area at baseline versus 0.5% at M12; p = 0.29). In contrast, the diabetic retinopathy severity score improved significantly between baseline and M12. Conclusions: Anti-VEGF treatment with aflibercept for diabetic macular edema had no impact on the retinal perfusion assessed by FA, but it allowed for artificially improving diabetic retinopathy severity scores.

Artifact-Removed Quantitative Analysis of Choriocapillaris Flow Voids.

To investigate choriocapillaris flow voids (FV) with a new optical coherence tomography angiography (OCTA) image processing strategy that can eliminate artifacts caused by vitreous opacities, sub-retinal pigment epithelium fluid and deposits, and subretinal fluid (SRF) by thresholding the en-face OCT image of the outer retina. We retrospectively reviewed medical records of patients with drusen and patients with active central serous chorioretinopathy (CSC). FV number (FVn), average area (FVav), and maximum area (FVmax) and the percentage of nonperfused choriocapillaris area (PNPCA) obtained using the proposed strategy were compared with those obtained by removing only artifacts caused by the superficial capillary plexus (SCP). The SRF group included 21 eyes with active CSC and the drusen group included 29 eyes with nonexudative age-related macular degeneration. FVav, FVmax, FVn, and PNPCA obtained using the algorithm were significantly lower than those obtained by removing only SCP-related artefacts in both groups (all p<0.05). The algorithm was also able to remove 96.9% of artifacts secondary to vitreous opacities and all artifacts secondary to serous pigment epithelial detachments. Choriocapillaris nonperfusion areas on OCTA images may be overestimated in eyes with RPE abnormalities and SRF due to artifacts. These artifact areas on choriocapillaris OCTA images can be removed using thresholded images of the outer retina en-face OCT scans. Our new artifact-removal strategy is useful in the assessment of choriocapillaris FV in eyes with SRF, drusen, drusen-like deposits, and pigment epithelial detachment.

Prevalence of venous loops and association with retinal ischemia in diabetic retinopathy using widefield swept-source OCT angiography.

To investigate the prevalence and clinical characteristics of diabetic patients with retinal venous loops (RVLs) and to assess the association with retinal ischemia using widefield swept-source optical coherence tomography angiography (WF SS-OCTA). In this retrospective, cross-sectional study, a total of 195 eyes of 132 diabetic patients (31 eyes with no diabetic retinopathy (DR), 76 eyes with nonproliferative DR (NPDR), and 88 eyes with proliferative DR (PDR)) were imaged with WF SS-OCTA using Angio 6 × 6mm and Montage 15 × 15mm scans. Quantitative ischemia-related parameters, including ischemia index (ratio of nonperfusion area to total retinal area), foveal avascular zone (FAZ), and neovascularization features, were evaluated. RVLs were classified as type I or type II according to the branching level of the feeder vessel. A multivariate generalized estimating equations (GEE) logistic regression model was used to analyze the association of systemic parameters and ischemia-related metrics with RVLs in PDR eyes. Forty-eight RVLs were identified in 22 eyes (11.28%). The prevalence of RVLs was higher in PDR compared to NPDR eyes (21.59% vs. 3.95%, P < 0.05). Type II RVLs accounted for a higher proportion than type I (89.58% vs. 10.42%, P < 0.001). RVLs were more likely to originate from superior (vs. inferior) and temporal (vs. nasal) veins (P < 0.05). The GEE model showed that neovascularization (NV) flow area and diastolic blood pressure were associated with RVLs in the PDR group (P < 0.05). WF SS-OCTA is useful for the identification of RVLs in patients with DR. NV flow area and diastolic blood pressure were associated with the presence of RVLs in eyes with PDR. Ischemia index, FAZ, and other WF SS-OCTA parameters were not associated with RVLs. Further longitudinal studies are needed to identify the role of RVLs in DR progression.

Predictive factors for microvascular recovery after treatments for diabetic retinopathy

BackgroundTo identify factors associated with microvascular recovery after intravitreal bevacizumab or panretinal photocoagulation (PRP) in diabetic retinopathy (DR).MethodsWe retrospectively reviewed 320 eyes/patients with DR treated with intravitreal bevacizumab and/or PRP. Two consecutive fluorescein angiographies (FAs) of each eye were compared. The number of microaneurysms and the area of capillary non-perfusion were calculated automatically using ImageJ software. Microvascular recovery was defined as a marked reduction in the numbers of microaneurysms (< 20%) or a marked reduction in the area of capillary non-perfusion (< 50%) in 45-degree fields or a complete regression of new vessels in ETDRS 7 standard fields. Baseline FA findings and changes in the ocular and systemic factors were analyzed.ResultsTwenty-eight (8.8%) of the 320 total eyes were found to meet the criteria of microvascular recovery after the treatments. Multivariate analysis revealed the presence of diffuse capillary telangiectasis (P = .003) and late disc leaking (P = .007) on baseline FA and a reduction of glycated hemoglobin (P = .005) during the follow-up period were predictive factors of microvascular recovery after the treatments. Although the microvascular recovery group presented with a significant improvement of BCVA after the treatments, the baseline BCVA could not predict the microvascular recovery after the treatments.ConclusionsDiffuse capillary telangiectasis or late disc leaking on baseline FA and improved glycemic control positively predicted the microvascular recovery after treatments for DR.

Clinical features of retinal amyloid angiopathy with transthyretin Gly83Arg variant.

To report on the clinical features of patients with retinal amyloid angiopathy (RAA) who were identified to be caused by the transthyretin (TTR) Gly83Arg variant. Case series of five patients diagnosed with RAA was collected at Affiliated Hospital of Zunyi Medical University from January 2010 to December 2021. The clinical features, therapeutic strategies, and prognoses of all patients were reviewed. Five patients with a mean age of 52.00±7.23y were diagnosed as RAA. These patients were previously diagnosed with hereditary transthyretin amyloidosis caused by the TTR Gly83Arg variant. Vitreous opacity was found in all 10 eyes, and 7 eyes developed RAA 2 to 20y after the onset of hereditary transthyretin amyloidosis. The clinical manifestations were recurrent vitreous hemorrhage in 2 eyes (29%), neovascular glaucoma in 2 eyes (29%), and iris neovascularization in 1 eye (14%). Microangioma lesions were found in all affected eyes that underwent fundus fluorescein angiography (FFA) in this group of cases, and the incidence of the retinal non-perfusion area was 67%. Although no cases of retinal neovascularization were found, the prognosis of visual acuity was not ideal. This is the first report of RAA in patients with the TTR Gly83Arg variant. Complications such as RAA and glaucoma will seriously affect the visual prognosis of patients. Thereafter, regular ophthalmic follow-up of patients with hereditary transthyretin amyloidosis is essential. And FFA after vitrectomy is very important, which can help ophthalmologists detect RAA earlier and treat it in time.

Healing rate of macular edema secondary to branch retinal vein occlusion in two years after initiation of intravitreal ranibizumab later combined with other treatment as needed and characteristics of refractory cases.

To investigate the 2-year healing rate of macular edema (ME) secondary to branch retinal vein occlusion (BRVO) treated initially with intravitreal ranibizumab (IVR) and later combined with other treatment as needed, and the characteristics of refractory cases. 130 patients (130 eyes) with BRVO-ME who received IVR initially were studied. Anti-vascular endothelial growth factor drug was additionally administered when ME relapsed or persisted. Photocoagulation was performed when the non-perfusion area (NPA) was ≥5 disc diameter (DD), and/or when ME relapsed due to microaneurysm. Patients were classified into a healed group [ME resolved in <2 years or mild ME remained without best-corrected visual acuity (BCVA) loss for ≥6 months] or refractory group (ME persisted for ≥2 years). 110 eyes were classified into the healed group, and 20 eyes into the refractory group. The healed group and refractory group had, respectively, mean follow-up periods of 21.2 and 37.4 months, and frequencies of NPA ≥5 DD of 55.5 and 25.0% (p = 0.015). In the healed group, mean BCVA (logMAR) improved significantly compared to baseline in all the periods until 24 months after treatment initiation and at the last visit (p<0.001). In the refractory group, mean BCVA improved significantly compared to baseline until 12 months after treatment initiation (p<0.05 for all periods), but was not significantly different at 18 or 24 months or at the last visit. In patients with BRVO-ME treated initially with IVR and later given additional treatments as needed, the healing rate was 84.6%. In eyes that healed within 2 years, BCVA improved relative to baseline throughout 24 months and at the last visit. In refractory eyes, BCVA improved only until 12 months, and thereafter deteriorated to baseline level at the last examination.

Quantitative Wide-Field Swept-Source Optical Coherence Tomography Angiography and Visual Outcomes in RAO.

Retinal artery occlusion (RAO) is an ophthalmic emergency that can lead to poor visual outcomes and is associated with an increased risk of stroke and cardiovascular events. Wide-field swept-source OCT-A (WF SS-OCTA) can provide quick and non-invasive angiographic information with a wide field of view. Here, we looked for associations between OCT-A vascular imaging metrics and vision in RAO patients. Patients with diagnoses of central (CRAO) or branched retinal artery occlusion (BRAO) were included. 6mm × 6mm Angio and 15mm × 15mm AngioPlex Montage OCT-A images were obtained for both eyes in each patient using Zeiss Plex Elite 9000 WF SS-OCTA device. Each 6mm × 6mm image was divided into nine Early Treatment Diabetic Retinopathy Study (ETDRS) subfields. Non-perfusion area (NPA) was manually measured using 15mm × 15mm images. A linear regression model was utilized to identify correlation between imaging metrics and vision. P-values less than 0.05 were considered as statistically significant. Twenty-five subjects were included. For RAO eyes, there was a statistically significant inverse correlation between retinal thickness as well as superficial capillary plexus (SCP) vessel density (VD) and vision. An inverse correlation was found between deep capillary plexus (DCP) VD and vision without statistical significance. There was a positive correlation between choroidal thickness as well as choroidal volume and vision without statistical significance. No significant correlation was found between the metrics and vision in contralateral eyes. For NPA and vision, no significant correlation was identified. This is the first study to investigate the utility of WF SS-OCTA in RAO and to demonstrate correlations between retinal vascular imaging metrics and visual outcomes. The results of this study provide a basis to understand the structural changes involved in vision in RAO and may guide management of RAO and prevention of cerebral stroke and cardiovascular accidents.

Retinal Capillary Nonperfusion in Preclinical Diabetic Retinopathy

Introduction: The aim of the study was to identify retinal microvascular changes using optical coherence tomography angiography (OCTA) in type 2 diabetes (T2D) patients with preclinical retinopathy identified by ultra-widefield fundus photography (UWF-FP). Methods: This is a cross-sectional observational study. All patients underwent UWF-FP 200° examinations with OPTOS California (Optos, Dunfermline, UK) and Cirrus AngioPlex® spectral-domain (SD)-OCTA 3 × 3 mm acquisitions (ZEISS, Dublin, CA, USA). The absence of visible lesions was identified using UWF-FP. Results: One hundred and ninety three eyes of individuals with T2D with no visible lesions in the fundus and identified in a screening setting were included in the study. Skeletonized vessel density (SVD), perfusion density (PD), and areas of capillary nonperfusion (CNP) values on SD-OCTA were significantly decreased when compared with healthy population (p < 0.001). SVD and CNP values of the superficial capillary plexus (SCP) were more frequently decreased (35% and 45%, respectively) than SVD values of the deep capillary plexus (DCP) (9% and 15%, respectively), demonstrating that diabetic microvascular changes occur earlier in the SCP than in the DCP. The ischemic phenotype, identified by a definite decrease in SVD or CNP in the SCP may, therefore, be identified in the preclinical stage of diabetic retinal disease. Conclusions: Retinal capillary nonperfusion detected by OCTA metrics of SVD and CNP can be identified in the central retina in eyes with T2D before development of visible lesions in the retina. Our findings confirm the relevance of OCTA to identify macular microvascular changes in the initial stages of diabetic retinopathy, allowing the identification of its ischemic phenotype very early in the disease process.

A rare case of unilateral traumatic peripheral retinal arteriolar occlusions and neovascularization of optic disc

A young adult Asian Indian male presented to us with a 1-month history of trauma to the right eye (RE) with a tennis ball. He had intraocular pressure (IOP) of 32 mmHg while on three topical antiglaucoma drugs and oral acetazolamide, with uncontrolled inflammation in the anterior chamber (AC) and arteriolar occlusions in the periphery. His best corrected visual acuity was 20/20 in RE. Fluorescein angiography of the RE showed the presence of neovascularization of disc (NVD). Magnetic resonance angiography of the head and neck, and blood investigations ruled out the embolic origin of arteriolar occlusion and systemic causes for inflammation. Intra ocular pressure (IOP) and inflammation were controlled with appropriate treatment. NVD resolved with photocoagulation treatment (PRP) for capillary non-perfusion areas in 4 weeks. This case documents the occurrence of arteriolar occlusion, with neovascularization after arteriolar occlusion post blunt trauma, and successful adjunct use of topical cyclosporine in the management of AC inflammation and high IOP.

Diffusion-weighted imaging as a non-gadolinium alternative for immediate assessing nonperfused area of adenomyosis after magnetic resonance-guided focused ultrasound (MRgFUS) ablation: a potential technique but with slightly overestimate

Diffusion-weighted imaging as a non-gadolinium alternative for immediate assessing nonperfused area of adenomyosis after magnetic resonance-guided focused ultrasound (MRgFUS) ablation: a potential technique but with slightly overestimate

Neuroprotective Effects of Human Adipose–Derived Mesenchymal Stem Cells in Oxygen-Induced Retinopathy

This study was designed to provide evidence of the neuroprotective of human adipose–derived mesenchymal stem cells (hADSCs) in oxygen-induced retinopathy (OIR). In vivo, hADSCs were intravitreally injected into OIR mice. Various assessments, including HE (histological evaluation), TUNEL (terminal deoxynucleotidyl transferase dUTP nick end labeling) staining, electroretinogram (ERG) analysis, and retinal flat-mount examination, were performed separately at postnatal days 15 (P15) and 17 (P17) to evaluate neurological damage and functional changes. Western blot analysis of ciliary neurotrophic factor (CNTF), glial cell line–derived neurotrophic factor (GDNF), and brain-derived neurotrophic factor (BDNF) was conducted at P17 to elucidate the neuroprotective mechanism. The P17 OIR group exhibited a significant increase in vascular endothelial cell nuclei and neovascularization that breached the ILM (inner limiting membrane) to the P17 control group. In addition, the retinal nonperfusion areas in the P17 OIR group and the number of apoptotic retinal cells in the P15 OIR group were significantly higher than in the corresponding hADSCs treatment group and control group. There was no significant thickness change in the inner nuclear layer (INL) but the outer nuclear layer (ONL) in the P17 OIR treatment group compared with the P17 OIR group. The cell density in the INL and ONL at P17 in the hADSCs treatment group was not significantly different from the OIR group. The amplitude of a-wave and b-wave in scotopic ERG analysis for the P17 OIR group was significantly lower than in the P17 hADSCs treatment group and the P17 control group. Furthermore, the latency of the a-wave and b-wave in the P17 OIR group was significantly longer than in the P17 hADSCs treatment group and the P17 control group. In addition, the expression levels of CNTF and BDNF in the P17 OIR group were statistically higher than those in the P17 control group, whereas the expression of GDNF was statistically lower in the P17 OIR group, compared with the P17 control group. The expression of CNTF and GDNF in the P17 hADSCs treatment group was statistically higher than in the P17 OIR group. However, the expression of BDNF in the P17 hADSCs treatment group was statistically lower than in the P17 OIR group. This study provides evidence for the neuroprotective effects of hADSCs in OIR.

Retinal haemorrhages on ultra-widefield red channel images and perfusion status in central retinal vein occlusion.

To evaluate the relationship between retinal haemorrhages detected on Ultra-widefield (UWF) red channel images and perfusion status in eyes with acute central retinal vein occlusion (CRVO). UWF fundus images were split into green and red channels using ImageJ software. The retinal haemorrhages were calculated quantitatively with both the green and red channel images, resulting in green channel haemorrhages (GCH) and red channel haemorrhages (RCH). The nonperfusion area (NPA) was also calculated from fluorescein angiography in each eye. The relationships between both the GCH and RCH with the NPA were investigated. Thirty-two eyes of 32 patients with acute CRVO (18 men, 14 women) were included. The mean GCH and RCH values were 10.4% ± 8.2% and 1.7% ± 1.7%, respectively. The mean NPA was 39.2% ± 28.8%. Significant correlations were seen between the GCH and NPA (r = 0.38; P = 0.022) and RCH and NPA (r = 0.44; P = 0.010, linear regression analysis). Multivariate analysis suggested that only the RCHs were correlated significantly with the NPA. Retinal haemorrhages detected by UWF red channel imaging were less compared to green channel imaging and associated closely with retinal NPAs in eyes with acute CRVO. UWF red channel imaging allowed us to identify ischaemia-related haemorrhage.

Neuropathologic findings in a young woman 4years following declaration of brain death: case analysis and literature review.

Brain death (death by neurologic criteria) is declared in 2% of all in-hospital deaths in the United States. Published neuropathology studies of individuals maintained on cardiorespiratory support are generally decades old, and notably include only 3 cases with long intervals between brain and "somatic" death (68 days, 101 days, 20 years). Here, we share our observations in a young woman supported for nearly 4½ years following declaration of brain death after oropharyngeal surgery. While limited by tissue availability and condition, we found evidence of at least partial perfusion of the superficial cerebral and cerebellar cortices by external carotid and vertebral arteries (via meningeal and posterior pharyngeal branches), characterized by focal cellular reaction and organization. Dural venous sinuses had thrombosis and recanalization, as well as iron deposition. In nonperfused brain areas, tissue "mummification," akin to that seen in certain postmortem conditions, including macerated stillbirths and saponification (adipocere formation), was identified, and are reviewed herein. Unfortunately, correlation with years-earlier clinical and radiographic observations was not possible. Nevertheless, we feel that our careful neuropathologic inspection of this case expands the understanding of the spectrum of human brain tissue alterations possible in a very rarely seen set of conditions.

Deep-learning-based AI for evaluating estimated nonperfusion areas requiring further examination in ultra-widefield fundus images

We herein propose a PraNet-based deep-learning model for estimating the size of non-perfusion area (NPA) in pseudo-color fundus photos from an ultra-wide-field (UWF) image. We trained the model with focal loss and weighted binary cross-entropy loss to deal with the class-imbalanced dataset, and optimized hyperparameters in order to minimize validation loss. As expected, the resultant PraNet-based deep-learning model outperformed previously published methods. For verification, we used UWF fundus images with NPA and used Bland–Altman plots to compare estimated NPA with the ground truth in FA, which demonstrated that bias between the eNPA and ground truth was smaller than 10% of the confidence limits zone and that the number of outliers was less than 10% of observed paired images. The accuracy of the model was also tested on an external dataset from another institution, which confirmed the generalization of the model. For validation, we employed a contingency table for ROC analysis to judge the sensitivity and specificity of the estimated-NPA (eNPA). The results demonstrated that the sensitivity and specificity ranged from 83.3–87.0% and 79.3–85.7%, respectively. In conclusion, we developed an AI model capable of estimating NPA size from only an UWF image without angiography using PraNet-based deep learning. This is a potentially useful tool in monitoring eyes with ischemic retinal diseases.

Retinal and intracranial arteriovenous malformations in Wyburn–Mason syndrome

A 12-year-old female presented with left exotropia for 1 year. The left eye fundus revealed dilation and tortuosity of the retinal arteries and veins consistent with group 3 retinal arteriovenous malformation (AVM; Fig. 1A). Fundus fluorescein angiography showed AVM filling without leakage but with a temporal nonperfusion area (Fig. 1B). Magnetic resonance angiogram of the head and cerebral angiography showed left orbital and suprasellar AVMs (Fig. 1C, D). The patient was diagnosed with Wyburn–Mason syndrome. No treatment was recommended for the intracranial AVMs because of the associated surgical risk to the perforators and the visual pathway.

WF SS-OCTA for detecting diabetic retinopathy and evaluating the effect of photocoagulation on posterior vitreous detachment.

This study aimed to assess the clinical usefulness of widefield swept source optical coherence tomography angiography (WF SS-OCTA) for detecting microvasculature lesions in diabetic retinopathy (DR) by comparing it with ultra-widefield fluorescein angiography (UWFFA) and to investigate the effect of panretinal photocoagulation (PRP) on posterior vitreous detachment (PVD) status. Patients with severe non-proliferative DR (NPDR) or proliferative DR (PDR) who were initially treated with PRP were enrolled. They underwent WF SS-OCTA with a 12×12-mm scan pattern of five visual fixations at baseline and at least a 3-month follow-up after PRP treatment. Patients with no contraindications underwent imaging with UWFFA within a week. Images were evaluated using two methods for the areas of the visible field of view (FOV), non-perfusion area (NPA), presence of neovascularization of the disc (NVD), neovascularization elsewhere (NVE), and PVD status. In total, 44 eyes of 28 patients with DR that were initially treated with PRP were analyzed. The FOV of the UWFFA was significantly wider than that of the WF SS-OCTA. The quantitative measurement of the NPAs was consistent between the two methods. NPAs more than 5DA outside the panoramic OCTA imaging area were detected in 1 eye with NPDR (8.3%) and in 10 eyes with PDR (47.8%). WF SS-OCTA had high detection rates for NVDs and NVEs, with a low rate of false positives. After PRP treatment, no eyes indicated progression in the PVD stages around the macula, optical disc, or NVEs at the short follow-up. WF SS-OCTA is clinically useful for evaluating NPAs and neovascularization in DR. PRP treatment does not induce PVD development in the short term.