Areas Of Nonperfusion Research Articles

Retinal hypoperfusion detected by wide-field optical coherence tomographic angiography in a case of retinal racemose hemangioma.

Retinal racemose hemangioma (RRH) is a rare, non-hereditary arteriovenous malformation characterized by the appearance of dilated and tortuous retinal vessels. RRH can develop complications associated with retinal ischemia, such as vitreous hemorrhage, retinal vein occlusion and neovascular glaucoma. Here, we report a case of RRH with retinal hypoperfusion detected by wide-field swept source optical coherence tomography angiography (OCTA), which was not unambiguously illustrated by fluorescein angiography (FA). Case report. A 57-year-old woman was referred to our hospital for the evaluation of severe retinal vascular tortuosity, dilation and retinal hemorrhages in the left eye. Fundus examination revealed arteriovenous communications temporal to the fovea and multiple microaneurysms surrounded by retinal hemorrhages at the midperipheral temporal fundus. In FA, multiple hyperfluorescent lesions with leakage corresponding to microaneurysms were observed in the temporal and lower midperipheral areas; however, non-perfused areas were apparently absent. By contrast, wide-field OCTA clearly showed low-density retinal capillaries in the superotemporal quadrant in comparison with those in the inferotemporal quadrant. Wide-field OCTA detected sparse retinal capillaries, which were not well illustrated by FA, in a patient with RRH. This indicates the presence of low-grade retinal hypoperfusion caused by altered retinal hemodynamics, potentially leading to ischemia-related retinal disorders during a prolonged course, in patients with clinically quiescent RRH.

Relationship between nonperfusion area from widefield optical coherence tomography angiography and macular vascular parameters in diabetic retinopathy

PurposeTo evaluate the relationship between the nonperfusion area (NPA) from widefield optical coherence tomography angiography (OCTA) and macular vascular parameters in diabetic retinopathy (DR).MethodsIn total, 51 eyes from 51 patients with proliferative DR (PDR) or moderate/severe non-PDR were included. Widefield OCTA using the Zeiss Plex Elite 9000 was performed. A semi-automatic algorithm calculated the percentages of the NPA within the total image. Macular OCTA (3 × 3 mm and 6 × 6 mm area) was scanned using the RTVue-XR Avanti. Vessel density (VD) was automatically separated into the superficial (SCP) and deep capillary plexus (DCP), and foveal avascular zone (FAZ) measurements were computed according to the parafoveal (1–3 mm) and perifoveal (3–6 mm) regions.ResultsA negative correlation was found between the average VD of the SCP and DCP obtained 3 × 3 mm and 6 × 6 mm area and the NPA. Multiple regression analysis revealed that the temporal–perifoveal region most negatively correlated with the NPA (r = − 0.55, p < 0.0001). No correlation was found between FAZ measurements and DR severity (area, p = 0.07; perimeter, p = 0.13).ConclusionDiabetic macular nonperfusion was significantly associated with the NPA from widefield OCTA. In particular, the temporal–perifoveal DCP disorder may be a sensitive indicator of wide NPA.

Inference of Capillary Nonperfusion Progression on Widefield OCT Angiography in Diabetic Retinopathy.

The purpose of this study was to explore the spatial patterns of the nonperfusion areas (NPAs) on widefield optical coherence tomography angiography (OCTA) images in diabetic retinopathy (DR) and to investigate their associations with NPA progression and DR severity. We prospectively enrolled 201 eyes from 158 patients with DR. Widefield images were obtained using a swept-source OCTA device (Xephilio OCT-S1), followed by the creation of 20-mm (1614 pixels) en face images. Nonperfusion squares (NPSs) were defined as 10 × 10-pixel squares without retinal vessels. Eyes with high-dimensional spatial data were mapped onto a two-dimensional space using the uniform manifold approximation and projection algorithm and divided by clustering. The patterns of NPA distribution were statistically compared between clusters. All eyes were mapped onto a two-dimensional space and divided into six clusters based on the similarity of NPA distribution. Eyes in clusters 1 and 2 had minimal and small NPAs, respectively. Eyes in clusters 3 and 4 exhibited NPAs in the temporal and inferotemporal regions, respectively. Eyes in cluster 5 displayed NPAs in both superonasal and inferonasal areas. The unique NPA distributions in each cluster encouraged us to propose eight possible pathways of NPA progression. DR severity was not equal between clusters (P < 0.001), for example, 8 (15.7%) of 51 eyes and 15 (65.2%) of 23 eyes had PDR in clusters 1 and 5, respectively. Dimensionality reduction and subsequent clustering based on the NPA distribution on widefield OCTA enabled the inference of possible NPA progression in DR.

Influence of Remote Ischemic Conditioning and Nitrogen Monoxide on Angiogenesis and Microcirculation in a Mouse Ear Burn Model

IntroductionRemote ischemic conditioning (RIC) has been shown to improve tissue resilience against ischemia. The aim of this study was to investigate the influence of RIC and its key factor, nitrogen monoxide (NO), on angiogenesis in a burn wound. Materials and methodsA unilateral burn injury on the ear of hairless mice (n = 48) was generated via a hot air jet in a contact-free manner. In four randomized groups, including the control (NoRIC group), RIC alone (RIConly group), RIC plus NO donor (ISDN group), and RIC plus NO synthase inhibitor (L-NAME group), the impact on angiogenesis, vessel diameter, blood flow, edema formation, and leukocyte-endothelial-cell interaction was evaluated over a 12-d period using intravital fluorescence microscopy. ResultsTissue perfusion was significantly improved by RIC (Day 3: ISDN group showed 182% and RIConly group showed 200% of baseline [BL], P < 0.001), while angiogenesis was not improved by RIC (nonperfused area on Day 12: mean 52% of BL in all groups, P >0.05). The application of ISDN did not further enhance the positive effect of RIC, whereas the application of L-NAME neutralized the effect of RIC. The most pronounced edema formation was observed in the RIConly group (mean 145% of BL, P ≤0.001), while the NoRIC group showed the least edema formation (Day 12: 117% of BL). ConclusionsRIC led to increased tissue perfusion, which did not result in improved angiogenesis, which may have been due to increased edema formation after RIC performance. The results of the present study do not support the establishment of a causal therapy strategy for burn wounds, including RIC.

An Analysis of Optical Coherence Tomography Angiography (OCT-A) Perfusion Density Maps in Patients Treated for Retinal Vein Occlusion with Intravitreal Aflibercept.

The primary goal of this study was to evaluate the reduction in non-perfusion area and improvement in blood flow as well as the reduction in retinal edema on optical coherence tomography angiography (OCT-A) in patients with retinal vein occlusion treated with 2 mg intravitreal injections of aflibercept. Fifty eyes of nine patients with central retinal vein occlusion (CRVO) and sixteen patients with branch retinal vein occlusion (BRVO), aged 50 to 75 years, were collectively analyzed as retinal vein occlusion (RVO). The following parameters were analyzed: superficial vessel density (VDSF), deep vessel density (VDD), flow area in the outer retina (FAOR), choriocapillaris flow area (FACC), non-flow area (NFA) and the foveal avascular zone (FAZ). OCT-A revealed a reduction in macular edema. The most significant change in central retinal thickness (CRT) was observed between measurement timepoint "5" and the baseline (46%). The non-flow area was also reduced. Following a significant decrease in superficial vessel density 30 days after the first dose of aflibercept, a non-significant increase was noted at the subsequent timepoints. An increase was also found in deep vessel density and choriocapillaris flow area. Improvements in the above OCT-A parameters resulted in increased retinal blood flow and improved visual acuity. Patients with retinal vein occlusion treated with 2 mg aflibercept exhibited reduced macular edema and FAZ, increased vessel density, improved blood flow, and better visual acuity.

Analysis of clinical progression of diabetic retinopathy in pregnant women with type 1 diabetes

This article presents clinical cases of progression of diabetic retinopathy (DR) in pregnant women with type 1 diabetes. The manifestation of pre-proliferative DR was related to the formation of focal macular edema in both eyes with nonperfusion areas of perimacular localization. Both eyes underwent laser coagulation of the retina. Following one month, the regression of macular edema in the left eye and hemorrhagic phenomena in both eyes with the appearance of new nonperfusion areas were observed. DR progression during pregnancy and in the postpartum period is determined by a number of factors, including compensation for diabetes mellitus, stabilization of retinopathy, and the presence of concomitant pathologies. In the aggressive course of proliferative DR, local traction retinal detachment and partial hemophthalmos of the left eye were revealed. Three stages of panretinal laser coagulation of both eyes were conducted, along with an endovitreal intervention with silicone tamponade on the left eye. At 28 weeks of gestation, progression of retinal neovascularization with extensive areas of nonperfusion in the posterior pole was observed in the right eye. Compaction of the laser coagulation areas of the retina in the right eye was performed.

An artificial intelligence system for the whole process from diagnosis to treatment suggestion of ischemic retinal diseases

Ischemic retinal diseases (IRDs) are a series of common blinding diseases that depend on accurate fundus fluorescein angiography (FFA) image interpretation for diagnosis and treatment. An artificial intelligence system (Ai-Doctor) was developed to interpret FFA images. Ai-Doctor performed well in image phase identification (area under the curve [AUC], 0.991-0.999, range), diabetic retinopathy (DR) and branch retinal vein occlusion (BRVO) diagnosis (AUC, 0.979-0.992), and non-perfusion area segmentation (Dice similarity coefficient [DSC], 89.7%-90.1%) and quantification. The segmentation model was expanded to unencountered IRDs (central RVO and retinal vasculitis), with DSCs of 89.2% and 83.6%, respectively. A clinically applicable ischemia index (CAII) was proposed to evaluate ischemic degree; patients with CAII values exceeding 0.17 in BRVO and 0.08 in DR may be associated with increased possibility for laser therapy. Ai-Doctor is expected to achieve accurate FFA image interpretation for IRDs, potentially reducing the reliance on retinal specialists.

Optical coherence tomography angiography in birdshot chorioretinopathy.

To describe the retinal vascular changes in birdshot chorioretinopathy (BSCR) using optical coherence tomography angiography (OCTA) and to compare them with changes in macular thickness. In this multicenter study, patients with a diagnosis of BSCR and a positive HLA-A29 underwent fluorescein angiography, spectral domain optical coherence tomography (SD-OCT), and OCTA. The foveal avascular zone (FAZ) and the area of capillary non-perfusion were manually measured by two examiners in fluorescein angiography (FA) and 3 × 3-mm OCTA images of the superficial retinal layer. These measurements were compared to central retinal thickness. To calculate normal capillary density, we collected data from 22 controls who had OCTA performed on one visit only. A total of 44 eyes with BSCR were enrolled. The mean automated parafoveal superficial capillary density in BSCR eyes was 0.47 ± 0.03. The differences between the foveal capillary density of BSCR patients and healthy subjects were statistically significant (P < 0.001). The mean area of FAZ manually measured on the 3 × 3 mm unsegmented OCTA images was larger in eyes with BSCR (1.34 ± 0.41 mm2; P < 0.0001). Measurement of FAZ area showed good interobserver (κ 0.88) and intraobserver repeatability (κ 0.79) on OCTA images. The intraclass correlation coefficient for FAZ measurements on FA between the two observers was 0.48. The OCT retinal thickness maps of all BSCR eyes demonstrated statistically significant thinning compared to those of control subjects (P < 0.01). Our study demonstrates the potential contribution of OCTA as a new non-invasive imaging technology that monitors disease activity in BSCR patients.

Assessment of early macular microangiopathy in subjects with prediabetes using optical coherence tomography angiography and fundus photography.

Early detection of retinal microangiopathy in patients with prediabetes may reduce diabetic retinopathy complications. The aim of this study was to assess early macular vascular changes in prediabetics before development of over diabetes using OCTA and fundus photography. In this cross-sectional study, 66 prediabetic individuals and 66 normal controls underwent clinical, laboratory, and fundus photography evaluation followed by OCTA macular imaging to examine for the foveal avascular zone, and area of capillary non-perfusion, thickness, disorganization of vessels, and vessel density perfusion percentage of superficial capillary plexus and deep capillary plexus. Retinal microangiopathy was detected in 36.4% of prediabetics by OCTA and only in 10.6% by fundus photography. None of clinical or laboratory parameters had significant association with DR. Area of capillary non-perfusion and disorganization of SCP were detected in 53.8% and 56.8%, respectively, in prediabetics. VDP of SCP and DCP of whole image, parafoveal, and perifoveal areas was significantly lower in prediabetes group compared to normal control. VDP of DCP of perifoveal area (β coefficient: - 0.10, OR: 0.91, 95% CI: 0.86-0.96, P < 0.001) and disorganization of DCP (β coefficient: 1.93, OR: 6.89, 95% CI: 2.5-18.8, P < 0.001) were significant predictors of DR in prediabetics. There was no difference in FAZ in prediabetics with and without retinopathy. OCTA could detect early retinal vascular changes during the prediabetic state before developing diabetes. VDP was significantly reduced in prediabetic patients. Furthermore, VDP of DCP of perifoveal area and disorganization of DCP were the most important predictors of retinopathy in prediabetic patients.

A new phenotype or retinal involvement in Steinert Disease: a case report.

To report a case illustrating the association of Steinert Disease (SD) with peripheral retinal non-perfusion areas and epiretinal membrane. Case report. A 47-year-old Caucasian female diagnosed with SD was referred for blurred vision in her right eye (RE). She presented bilateral ptosis with deficit of elevator muscle.Dilated fundus examination revealed altered macular reflex, peripheral vascular alterations, and ghost vessels bilaterally. Structural spectral domain optical coherence tomography (SD-OCT) showed an epiretinal membrane with a partial alteration of the foveal profile in the RE. Optical coherence tomography angiography (OCTA) images revealed no evidence of neovascular membrane in the macular region. Fluoresceine angiography (FA) showed retinal peripheral non perfusion areas and leakage in the late phases of the examination. Any retinal alteration should be considered during the ophthalmological examination of patients suffering from type 1 myotonic dystrophy. OCT and fluoresceine angiography should be performed evaluating the SD patient that complains about visual impairment.

Renal artery aneurism and renal autotransplantation: review of surgical technique, preoperative complementary examinations and postoperative follow-up protocol

Introduction: Renal artery aneurysm (RAA) is a rare pathology; however, its incidental diagnosis is increasingly frequent due to the increasing use of imaging techniques. Complex (hilar) RAAs, dependent on the distal renal artery and its branches, constitute a subset of RAAs that present a therapeutic challenge due to their anatomical location and may require extracorporeal arterial repair and autotransplantation. Material and methods: A bibliographic review is carried out to homogenize the management of this pathology, analyzing the indications for surgical treatment, the recommended surgical technique step by step, as well as post-surgical monitoring. Two clinical cases of RAA treated in our center by hand-assisted laparoscopic nephrectomy, ex vivo bench repair and renal autotransplantation are presented. Results: In both cases, a postoperative Doppler ultrasound of the graft was performed 24 hours later, in which a renal graft was observed in the iliac fossa, of normal size and cortical thickness within normality with normal color Doppler signal, and spectral curves without alterations. Both patients presented oligoanuric acute renal failure (injury) during the immediate postoperative period (first 24 hours) with complete resolution at discharge, which occurred on the 11th and 12th postoperative day, respectively. In both patients a diuretic renogram with MAG3 was performed. In case 1, it was performed the third postoperative month and a slightly ectatic right kidney was observed with less perfusion and parenchymal incorporation of the radiotracer, with a reduction in relative renal function (39.47%) and MAG3 clearance (indeterminate renographic pattern). In this patient, a CT scan with the excretory phase was performed simultaneously, in which a grafted right kidney was seen at the level of the right iliac fossa with good contrast elimination in the excretory phase bilaterally and symmetrically. A small non-perfused area is observed in the upper pole. In the second patient, the renogram was performed on the 14th postoperative day, finding the morphofunctional study of the graft within normal parameters without detecting areas of hypoperfusion. The levels of creatinine and glomerular filtration were, respectively, in the first case: 0.86mg/dl and 90.19ml/min/1.73m2 preoperatively and 0.83mg/dl and 90.96ml/min/ 1.73m2 per postoperative month. In the second case, the values were: preoperatively creatinine of 0.66mg/dl and glomerular filtration rate of 97.96ml/min/1.73m2 and 0.81mg/dl and 89ml/min/1.73m2 one month postoperatively. Conclusion: After reviewing the literature, there is no consensus regarding the imaging techniques to be performed after renal autotransplantation and the optimal time frames for performing these for the evaluation of the postoperative graft. There is also no homogeneity in the imaging techniques to be performed in the preoperative assessment. In our experience, open ex vivo surgical repair of complex distal hilar RAAs has been successful with low morbidity and mortality and an acceptable rate of preservation of renal function.

Purtscher-like retinopathy in a 19-year-old with maturity-onset diabetes of the young: a case report

BackgroundWe report the first case of Purtscher-like retinopathy in a patient with 17q12 deletion-associated maturity-onset diabetes of the young.Case presentationA 19-year-old diabetic Hispanic male with history of cataracts and toe amputations presented with sudden onset of painless bilateral vision loss for 1 week with no associated trauma. Visual acuity was counting fingers at six feet in both eyes. Dilated retinal examination revealed bilateral peripapillary cotton wool spots and intraretinal hemorrhages, and significant subretinal and intraretinal fluid on optical coherence tomography. Fluorescein angiography revealed arteriolar staining and leakage around the disc with areas of capillary nonperfusion, supporting the diagnosis of Purtscher-like retinopathy. Systemic workup revealed multiple diabetic complications including chronic osteomyelitis of multiple toes, nonhealing diabetic foot ulcers, neurogenic bladder and bowel, and bilateral lower-extremity muscular neuropathies. Genetic evaluation revealed a 17q12 deletion, which is associated with maturity-onset diabetes of the young 5. On follow-up examination, he received a single intravitreal antivascular endothelial growth factor injection in the left eye (off label) for persistent macular edema. Although his retinal edema improved, his visual acuity remained poor.ConclusionsThe presentation of our patient’s multiple diabetic complications along visual symptoms suggests Purtscher-like retinopathy can be a sequela of uncontrolled diabetes. Purtscher-like retinopathy is a rare but possible consideration in diabetic patients who present with acute-onset vision loss.

Central and peripheral changes in the retina and choroid in patients with diabetes mellitus without clinical diabetic retinopathy assessed by ultra-wide-field optical coherence tomography angiography.

To explore the central and peripheral retinal and choroidal changes in diabetic patients without clinical diabetic retinopathy (DM-NoDR) using ultra-wide-field swept-source optical coherence tomography angiography (UWF-SS-OCTA). 67 DM-NoDR eyes and 32 age-matched healthy eyes were recruited. Retinal and choroidal parameters, including qualitative retinal microangiopathy, vessel flow (VFD) and linear density (VLD), thickness, and volume, were measured in the central and peripheral areas of the 24 × 20 mm2 UWF-SS-OCTA images. DM-NoDR eyes had significantly more nonperfusion area and capillary tortuosity than controls in the central and peripheral areas (p < 0.05). The presence of central capillary tortuosity was associated with higher levels of serum creatinine (OR 1.049, 95%CI 1.001-1.098; p = 0.044) and blood urea nitrogen (OR 1.775, 95%CI 1.051-2.998; p = 0.032) in DM-NoDR eyes. For DM-NoDR eyes versus controls, VFD in the 300-μm annulus around the foveal avascular zone, superficial capillary plexus (SCP), and full retina, and SCP-VLD significantly decreased, while VFD in the deep capillary plexus (DCP), retinal thickness, and retinal volume increased (p < 0.05). Analysis in the central and peripheral areas recapitulated all these findings, except for decreased peripheral thickness and volume and no difference in peripheral DCP-VFD. In DM-NoDR eyes, choriocapillaris-VFD, choroidal thickness, and choroidal volume increased in the central area, while VFD in the large and medium choroidal vessel layer decreased in the whole image (p < 0.05). Retinal and choroidal changes already existed in the central and/or peripheral areas of DM-NoDR eyes. UWF-SS-OCTA, enabling the visualization of the peripheral fundus area, is a promising image technique for the early detection of fundus changes in DM-NoDR patients.

Оценка макулярного кровотока с помощью оптической когерентной томографии-ангиографии у беременных женщин, страдающих сахарным диабетом

Purpose. To study retinal blood flow in pregnant women with disorders of carbohydrate metabolism using optical coherence tomography angiography (OCTA) in order to determine the criteria for the manifestation and progression of diabetic retinopathy (DR). Material and methods. 203 pregnant women in the third trimester were examined: 24 – with type 1 and 2 diabetes (T1D and T2D), 143 – with gestational diabetes (GD), and 36 apparently healthy women with physiological pregnancy, who consisted the control group. OCTA imaging was performed using the RTVue XR Avanti OCT 6 mm × 6 mm «Angio Retina» scan protocols (Optovue, USA). The whole image vessel density (wiVD), foveal vessel density (FVD), and foveal avascular zone (FAZ) area in the superficial capillary plexus were studied. Results. FVD in pregnant women with diabetes was significantly less than in pregnant women with GD and in the control group. In this connection, it can be assume changes of the retinal microvascular regulation, due to chronic disorders of carbohydrate metabolism in patients with diabetes, and development of microangiopathy. Enlargement of FAZ area and decrease of wiVD were revealed in patients with DR, relative to datas obtained in the group of pregnant women with diabetes and absence of DR, in the absence of differences in FVD indexes. In 2 patients with T1D and the absence of ophthalmoscopic signs of DR, OCTA revealed areas of nonperfusion in the posterior pole of the eye. Conclusion. OCTA helps to identify areas of retinal nonperfusion in the posterior pole of the eye in pregnant women with diabetes in the absence of ophthalmoscopic signs of DR and allows determining objective indications for timely retinal laser coagulation. Keywords: optical coherence tomography angiography, pregnancy, diabetic retinopathy, gestational diabetes, foveal avascular zone, retinal blood flow

Semi-automated algorithm using directional filter for the precise quantification of non-perfusion area on widefield swept-source optical coherence tomography angiograms.

The clinical application of optical coherence tomography angiography (OCTA) has been well documented in literature with its promising potential in dye-less evaluation of various retinal vascular pathologies. Recent advances in OCTA help us gather wider field of view with 12 mm × 12 mm and montage compared to the standard dye-based scans, which has a higher accuracy and sensitivity in detection of peripheral pathologies. The aim of this study is to build a semi-automated algorithm to precisely quantify the non-perfusion areas (NPAs) on widefield swept-source optical coherence tomography angiography (WF SS-OCTA). All subjects underwent imaging on 100 kHz SS-OCTA device acquiring 12 mm × 12 mm angiograms centered on fovea and optic disc. After a comprehensive literature review, a novel algorithm using FIJI (ImageJ) was designed to calculate the NPAs (mm2) after excluding the threshold and segmentation artifact areas from the total field of view. Segmentation and threshold artifacts were first removed from enface structure images using the spatial variance and mean filter respectively. Vessel enhancement was achieved by using 'Subtract Background' followed by directional filter. The cut off for Huang's fuzzy black and white thresholding was defined from the pixel values based of the foveal avascular zone. Then, the NPAs were calculated using the 'Analyze Particles' command with a minimum size of ~0.15 mm2. Finally, the artifact area was subtracted from to give the corrected NPAs. Our cohort had 44 eyes of 30 control patients and 107 eyes of 73 patients with diabetes mellitus (both median age 55 years, P=0.89). Of 107 eyes, 21 eyes had no evidence of diabetic retinopathy (DR), 50 eyes had non-proliferative DR and 36 eyes had proliferative DR. The median NPA was 0.20 (0.07-0.40) in controls, 0.28 (0.12-0.72) in no DR, 5.54 (3.12-9.10) in non-proliferative DR and 13.38 (8.73-26.32) in proliferative DR eyes. Using mixed effects-multiple linear regression analysis adjusting for age, there was significant progressive increase in NPA with increasing DR severity. This is one of the first study to use the directional filter for WFSS-OCTA image processing which is known to be superior to other Hessian based multiscale, linear, and non-linear filters especially for vascular analysis. Our method could greatly refine and streamline the calculation of signal void area proportion, while being much quicker and accurate than manual delineation of NPAs and subsequent estimation. This combined with the wide field of view can have a great prognostic and diagnostic clinical impact for future applications in DR and other ischemic retinal pathologies.

Результаты изучения ретинального кровотока у беременных с сахарным диабетом с помощью оптической когерентной томографии-ангиографии

Purpose. To study retinal blood flow in pregnant women with disorders of carbohydrate metabolism using optical coherence tomography angiography (OCTA). Material and methods. 203 pregnant women in the third trimester of pregnancy were examined: 24 — with type 1 and 2 diabetes (T1D and T2D), 143 — with gestational diabetes (GD), and 36 healthy women with physiological pregnancy, who consisted the control group. OCTA imaging was performed using the RTVue XR Avanti OCT 6 mm × 6 mm «Angio Retina» scan protocols (Optovue, USA). The vascular density (VD), vascular density in the fovea (VDF), and foveal avascular zone (FAZ) area in the superficial capillary plexus were studied. Results. Among studied patients no significant differences in VD and in FAZ area were found. VDF in pregnant women with diabetes was significantly less than in pregnant women with GD and in the control group. There were no significant differences in the studied parameters in groups with different periods of GD manifestation. In pregnant women with diabetes with presence and absence of DR, retinal blood flow did not differ significantly. Given the absence of differences of studied parameters in pregnant women with diabetes without DR and with DR, it can be assumed that the retinal microvascular regulation changes due to chronic disorders of carbohydrate metabolism in patients with diabetes and the development of microangiopathy. In 2 patients with T1D and the absence of ophthalmoscopic signs of DR, OCTA revealed areas of nonperfusion in the posterior pole of the eye. Conclusion. OCTA helps to identify areas of retinal nonperfusion in the posterior pole of the eye in pregnant women with diabetes in the absence of ophthalmoscopic signs of DR. Keywords: optical coherence tomography angiography, pregnancy, diabetic retinopathy, retinal blood flow

PREDICTION OF DIABETIC RETINOPATHY SEVERITY USING A COMBINATION OF RETINAL NEURODEGENERATION AND CAPILLARY NONPERFUSION ON OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY.

To generate a prediction model of diabetic retinopathy (DR) severity stages based on retinal neurodegeneration and capillary nonperfusion area (NPA) detected using optical coherence tomography (OCT) and OCT angiography (OCTA). A total of 155 treatment-naïve eyes were retrospectively included. Macular ganglion cell/inner plexiform layer (mGCIPL) thickness in six macular regions was measured. A custom algorithm was used to calculate capillary NPA from 3 × 3 mm 2 and 12 × 12 mm 2 field OCTA images. The region of interest was selected as circular areas of 3 mm and 12 mm diameter and divided into six subsections. Classification and regression tree analysis identified the best predictors to discriminate between the five DR stages. Inferotemporal sector showed the largest mean NPA, and the inferior hemispheric NPA was significantly larger compared with the superior hemisphere. The mean mGCIPL thickness was significantly correlated with NPA of 12 × 12 mm 2 field in participants with early stage DR. Inferior hemispheric NPA of 12 × 12 mm 2 field and mean mGCIPL thickness were the two best variables to discriminate no DR versus mild nonproliferative DR (NPDR) and mild versus moderate NPDR (accuracy: 88.8% and 93.5%). Meanwhile, a combination of NPA of 12 × 12 mm 2 and 3 × 3 mm 2 fields was the best prediction model to discriminate moderate versus severe NPDR and severe NPDR versus PDR (accuracy: 91.8% and 94.1%). A combination model of capillary NPA and mGCIPL thickness may be a novel biomarker for predicting DR severity. Capillary nonperfusion seems to initially occur in the midperipheral retina with macular neurodegeneration and progress posteriorly.

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 &lt; 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.