Small Vessels Research Articles

Cerebral small vessel injury in mice with damage to ACE2-expressing cerebral vascular endothelial cells and post COVID-19 patients.

The angiotensin-converting enzyme 2 (ACE2), which is expressed in cerebral vascular endothelial cells (CVECs), has been currently identified as a functional receptor for SARS-CoV-2. We specifically induced injury to ACE2-expressing CVECs in mice and evaluated the effects of such targeted damage through magnetic resonance imaging (MRI) and cognitive behavioral tests. In parallel, we recruited a single-center cohort of COVID-19 survivors and further assessed their brain microvascular injury based on cognition and emotional scales, cranial MRI scans, and blood proteomic measurements. Here, we show an array of pathological and behavioral alterations characteristic of cerebral small vessel disease (CSVD) in mice that targeted damage to ACE2-expressing CVECs, and COVID-19 survivors. These CSVD-like manifestations persist for at least 7 months post-recovery from COVID-19. Our findings suggest that SARS-CoV-2 may induce cerebral small vessel damage with persistent sequelae, underscoring the imperative for heightened clinical vigilance in mitigating or treating SARS-CoV-2-mediated cerebral endothelial injury throughout infection and convalescence. Cerebral small vessel disease-associated changes were observed after targeted damage to angiotensin-converting enzyme 2-expressing cerebral vascular endothelial cells. SARS-CoV-2 may induce cerebral small vessel damage with persistent sequelae. Clinical vigilance is needed in preventing SARS-CoV-2-induced cerebral endothelial damage during infection and recovery.

TNF-α inhibitors in the management of refractory granulomatosis with polyangiitis: A report of two cases

Granulomatosis with polyangiitis (GPA) is a type of antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) that causes granulomatous necrotizing inflammation of small blood vessels. The goal of AAV treatment is to create a long-term remission. For inducing remission, the European League Against Rheumatism recommends using glucocorticoids (GCs) in combination with either cyclophosphamide (CYC) or rituximab (RTX). Despite this, in 10-40% the disease is resistant to initial treatment. In this report, we present two cases of refractory GPA that successfully achieved long-term remission using tumor necrosis factor-α inhibitors. The first case is a 27-year-old woman with GPA with involvement of upper airway, breast and central nervous system with active disease despite treatment with high dose GCs, CYC and RTX, successfully treated with infliximab and the disease was in complete remission for 54 months. The second case is a 35-year-old man with GPA with arthritis, lung cavitary lesions and nephritis resistant to treatment with high dose GCs, CYC and RTX, treated with adalimumab and the disease was in complete remission for 40 months.

Myogenic response of the cerebral vessel: a mathematical model

The myogenic response is most typical for small arterial vessels and consists in constriction of the vessel with an increase in transmural pressure, the pressure difference between the inner and outer surfaces of the vascular wall. There are many models describing this response. In models of last decades, in addition to macrostretchings and macrostrains, their microanalogues are introduced into consideration, that significantly complicates the description. In the presented work a simple model of the wall of the small cerebral artery is described, which includes the main parameters that control the myogenic response and corresponds to physiological processes underlining this response. It is believed that active stresses depend on stretching and the concentration of free calcium ions in the cytoplasm of the smooth muscle cell. In turn, the calcium content depends on the membrane potential, determined by the pressure. An axisymmetric stationary problem is considered; the wall material in the non-activated state is assumed to be pseudoelastic. Calculations showed a qualitative difference in the dependence of active stress on stretching and its distribution in the radial direction before and after the development of the vascular response. The calculated diameter values before and after exposure to substances affecting the polarization of the smooth muscle cell membrane are within the range of experimental values. These results indicate that the introduction of the dependence of calcium concentration on membrane potential expands the area of applicability of simple models of this kind for evaluating the value of vascular diameter.

Peristaltic Flow of Jeffrey Fluid in an Inclined Porous Tube with Multi-Thrombosis

The fact that multiple thrombosis opposes blood flow and flow is rare in blood vessels is refined to a normal condition with catheter application. The inner surface of the circular blood arteries may not be smooth in the majority of diseased instances. Additionally, the small blood vessel peristalsis mechanism is formed. In this paper, we discuss a mathematical model for the flow of biological fluid (blood) in a circular tube with multi-thrombosis considered under peristaltic wave propagation. The blood flow in this tube is restricted due to the many thromboses present, and the flow is redesigned with the aid of a catheter. We model this non-Newtonian blood flow issue for Jeffrey fluid. In most pathological cases, the inner surface of the circular blood vessels may not be smooth. Further, the mechanism of the peristalsis is established for small blood vessels. Because of this biological phenomenon, the peristaltic movement of Jeffrey fluid in a porous annulus with slip is examined. Equations that govern energy and momentum are solved exactly, and graphical interpretation is made using mathematical software. Streamline graphs show the many thromboses that increase in height. The wall shear stress graphs show a sinusoidally advancing wave with peaks and dips of different amplitudes. This tube's unique crest and trough amplitude are caused by the presence of multiple thromboses. We obtained the impact of the pressure gradient on the permeability parameter (β). The pressure gradient falls as the permeability parameter rises.

Cardiac arrest and microcirculatory dysfunction: a narrative review.

This review provides an overview of the role of microcirculation in cardiac arrest and postcardiac arrest syndrome through handheld intravital microscopy and biomarkers. It highlights the importance of microcirculatory dysfunction in postcardiac arrest outcomes and explores potential therapeutic targets. Sublingual microcirculation is impaired in the early stage of postarrest and is potentially associated with increased mortality. Recent work suggests that the proportion of perfused small vessels is predictive of mortality. Microcirculatory impairment is consistently found to be independent of macrohemodynamic parameters. Biomarkers of endothelial cell injury and endothelial glycocalyx degradation are elevated in postarrest settings and may predict mortality and clinical outcomes, warranting further studies. Recent studies of exploratory therapies targeting microcirculation have shown some promise in animal models but still require significant research. Although research continues to suggest the important role that microcirculation may play in postcardiac arrest syndrome and cardiac arrest outcomes, the existing studies are still limited to draw any definitive conclusions. Further research is needed to better understand microcirculatory changes and their significance to improve cardiac arrest care and outcomes.

Cerebral salt wasting syndrome in an elderly patient with cerebral small vessel disease.

Hyponatremia is a common electrolyte disturbance seen among the acute geriatric admissions with two common diagnostic entities; the syndrome of inappropriate antidiuretic hormone (SIADH) and cerebral salt wasting syndrome (CSWS) that have different clinical and biochemical presentations, different pathogenesis and therapeutic approaches. Hyponatremia caused by CSWS in patients with cerebral small vessel disease (cSVD) a prevalent condition among the elderly, can be masked in geriatric patients with concomitant fluctuating neurological deficits. Correct diagnosis is crucial to appropriate management. In this case report we describe an association between hyponatremia caused by CSWS in a patient with cSVD.

A Novel Detection and Classification Framework for Diagnosing of Cerebral Microbleeds Using Transformer and Language.

The detection of Cerebral Microbleeds (CMBs) is crucial for diagnosing cerebral small vessel disease. However, due to the small size and subtle appearance of CMBs in susceptibility-weighted imaging (SWI), manual detection is both time-consuming and labor-intensive. Meanwhile, the presence of similar-looking features in SWI images demands significant expertise from clinicians, further complicating this process. Recently, there has been a significant advancement in automated detection of CMBs using a Convolutional Neural Network (CNN) structure, aiming at enhancing diagnostic efficiency for neurologists. However, existing methods still show discrepancies when compared to the actual clinical diagnostic process. To bridge this gap, we introduce a novel multimodal detection and classification framework for CMBs' diagnosis, termed MM-UniCMBs. This framework includes a light-weight detection model and a multi-modal classification network. Specifically, we proposed a new CMBs detection network, CMBs-YOLO, designed to capture the salient features of CMBs in SWI images. Additionally, we design an innovative language-vision classification network, CMBsFormer (CF), which integrates patient textual descriptions-such as gender, age, and medical history-with image data. The MM-UniCMBs framework is designed to closely align with the diagnostic workflow of clinicians, offering greater interpretability and flexibility compared to existing methods. Extensive experimental results show that MM-UniCMBs achieves a sensitivity of 94% in CMBs' classification and can process a patient's data within 5 s.

Genetic causality of lipidomic and immune cell profiles in ischemic stroke.

Ischemic stroke (IS) is a global health issue linked to lipid metabolism and immune cell responses. This study uses Mendelian randomization (MR) to identify genetic risk factors for IS subtypes using comprehensive genetic data from lipidomic and immune cell profiles. We assessed genetic susceptibility to IS across 179 lipids and 731 immune cell phenotypes using instrumental variables (IVs) from recent genome-wide association studies. A two-sample MR approach evaluated correlations, and a two-step MR mediation analysis explored the role of immune cell phenotypes in the lipid-IS pathway. Sensitivity analyses, including MR-Egger and Cochran Q tests, ensured robust results. Genetic IVs for 162 lipids and 614 immune cell phenotypes were identified. Significant genetic causality was found between 35 lipids and large artery stroke (LAS), with 12 as risk factors (sterol esters, phosphatidylcholines, phosphatidylethanolamines) and 23 as protective factors (phosphatidylcholines, phosphatidylethanolamines, phosphatidylinositols). For small vessel stroke (SVS), 8 as risk factors (sterol esters, phosphatidylcholines), and 2 as protective factors (phosphatidylinositol, sphingomyelin). For cardioembolic stroke (CS), 2 as risk factors, and 4 as protective factors. Mediation analysis revealed that CCR2 on granulocytes, CD11c on CD62L+ myeloid dendritic cells, and FSC-A on granulocytes mediated the lipid-immune cell-LAS pathway, while CD4 on activated CD4 regulatory T cells and CD4 on activated & secreting CD4 regulatory T cells mediated the lipid-immune cell-SVS pathway. This study identifies genetic links between specific lipids and IS subtypes, highlights immune cells' role in IS risk and mediation, suggests new therapeutic targets, and uncovers IS genetic drivers.

Myocardial Perfusion Scintigraphy in Diagnosic of Coronary Heart Disease

<i>Introduction: </i>Atherosclerosis plays a key role in the etiopathogenesis of cardiovascular diseases. Atherosclerosis is a generalized chronic inflammatory disease of the vascular wall, which results in anatomical and histological changes that, together with functional changes, lead to endothelial dysfunction, narrowing of the arterial lumen, and insufficient blood supply to the tissues. The shift in the incidence of cardiovascular diseases to younger age groups is alarming. The presence of microvascular changes in the myocardium is significant. The high incidence of cardiovascular diseases, especially ischemic heart disease, requires early diagnosis and modern treatment. <i>Aim: </i>The aim of the paper is to analyse and point out early diagnosis of coronary heart disease using nuclear medicine methods. <i>Set of examined patients and methodology: </i>Using nuclear medicine methods, we try to detect these changes in time and thus prevent the occurrence of acute coronary events. In nuclear cardiology, instead of a large-area scintillation detector, a new type of cardio-gamma camera "Discovery CZT 530c" based on the principle of semiconductor detectors began to be used. The abbreviation CZT stands for semiconductor composition (Cadmium-Zinc-Tellur). The set of respondents consisted of 4270 people examined in the years 2014-2016 by myocardial perfusion scintigraphy. There were 950 diabetic patients in the analysed group of the 4270 examined. <i>Results:</i> In the analysed group of 4270 respondents, 61% had negative findings and 39% had positive findings in terms of the presence of ischemic heart disease. In the group of diabetic patients, there was a negative finding in 28% of respondents and a positive finding in 72% of the respondents in the sense of positive ischemic heart disease. Using myocardial perfusion scintigraphy in the diagnosis of functional changes, we confirmed a great benefit in detecting early changes in coronary heart disease, including in the diagnosis of microvascular angina. <i>Conclusion:</i> Nuclear medicine methods are of great benefit for the diagnosis of small vessel disease, diabetic cardiomyopathy and cardiac autonomic neuropathy in patients with diabetes mellitus. The new type of cardio gamma camera "Discovery CZT 530c" allows more accurate assessment of myocardial perfusion abnormalities and at the same time the reduction of the radiopharmaceutical dose reduces the patient's radiation load by 50%.

Impact of Susceptibility Weighted MRI Sequences in Cerebral Small Vessel Disease

Impact of Susceptibility Weighted MRI Sequences in Cerebral Small Vessel Disease

CANVAS For A Diagnosis: Can You Hear The Hooves Of Zebras?

Abstract Background A 75year old male presented to a Movement Disorder Service with complex multimorbidity including: chronic pain, type 2 diabetes mellitus, hypoventilatory obesity syndrome, biliary calculus, moderate aortic stenosis, marked orthostatic hypotension, pulmonary hypertension, coronary artery bypass grafting, permanent pacemaker for complete atrioventricular block, carpal tunnel release bilaterally, polypharmacy and bilateral cataracts. History elucidated a distal to proximal sensory loss over 20years and neuropathic pain without nerve conduction confirmation; and progressively ataxic gait over several years. He also complained of hypophonia, bruxism, excessive daytime somnolence, passages, transitions, visual agnosia, textural illusion, oscillopsia, irritability, inflexibility, hoarding, impulsivity, disorganisation, inattention, apathy, depression and aspontaneity. He was intolerant of nocturnal continuous positive airway pressure device. Epworth score was 21. Methods Examination demonstrated: marked orthostatic hypotension, preserved cognition, hypersomnolence, dyspraxic dysgraphia, palmar and antecubital agraphaesthesia, downbeat horizontal nystagmus at eccentric gaze positions, square wave jerks, bidirectionally impaired head impulse test, dysmetric saccades, asymmetric cerebellar signs in upper and lower limbs, rightward Pisa syndrome, kinesigenic dystonic axial posturing, rightward laterocollis and equivocal Babinski/Oppenheim reflexes. Gait assessment demonstrated sensory and cerebellar ataxic features with marked apraxia. No pes cavus. Results Computed tomography of brain had Fazekas 1 small vessel disease, Medial temporal atrophy score 1, Koedam 1 and age-commensurate cerebral and cerebellar atrophy. RFC1 gene testing confirmed biallelic intronic AAGGG repeat expansion disorder. Conclusion Cerebellar Ataxia Neuropathy and Vestibular Areflexia Syndrome (CANVAS) should be considered in patients with presentations from mid-life of progressive sensory ataxic neuropathy, altered vestibular ocular reflex, gaze evoked nystagmus and prominent dysautonomia. CANVAS is a rare autosomal recessive genetic disorder with a protean presentation. Referral to Genetics Services should be undertaken for family counselling. Keeping an open mind in complex, multimorbid patients to a potentially unifying diagnosis is important to guide prognostication. The rumble of hooves in the distance is not always that of horses.

The impact of the COVID-19 pandemic on the incidence and clinical course of IgA vasculitis in paediatric patients

Introduction and objective: Immunoglobulin A vasculitis is an autoimmune disorder resulting from immune complex accumulation in small blood vessels, causing skin, joint, abdominal, and kidney manifestations. This study evaluated the impact of the COVID-19 pandemic on the incidence and clinical course of immunoglobulin A vasculitis in paediatric patients. Materials and methods: A retrospective analysis of medical records from a single university paediatric hospital was performed to compare 117 patients presenting with immunoglobulin A vasculitis before and 57 after the COVID-19 epidemic announcement in Poland on 20 March 2020. Laboratory results, hospitalisation duration, preceding infections, clinical presentation, history of allergies and COVID-19 vaccinations, and the proportion of immunoglobulin A vasculitis patients among all admissions were analysed. Results: The study of 174 patients showed that their average age during the pandemic (5.51 ± 3.10) was significantly lower than pre-pandemically (6.98 ± 3.67) (p < 0.05). Before the pandemic, more hospitalised patients had immunoglobulin A vasculitis (1.14%) compared to during the pandemic (0.47%) (p < 0.05). Food allergies were also more common during the pandemic (20.8%) than before (8.8%) (p < 0.05). No significant differences were found in hospitalisation duration, and the incidence of immunoglobulin A vasculitis nephritis and abdominal symptoms (p = 0.194, p = 0.381, p = 0.968, respectively). Three patients had COVID-19 infection at admission. Conclusions: The pandemic led to fewer immunoglobulin A vasculitis hospitalisations but did not alter the clinical course of the disease or the incidence of immunoglobulin A vasculitis nephritis. In the context of the resurgence of COVID-19 infections, it is important to consider them as potential factors affecting immunoglobulin A vasculitis. Ongoing research is essential to understand these dynamics and guide effective clinical management of immunoglobulin A vasculitis amidst the evolving COVID-19 setting.

NLRP3 inhibitor combined with Yimusake improves erectile dysfunction in rats with diabetes mellitus through the attenuation of pyroptosis

Erectile dysfunction (ED) is a prevalent complication associated with diabetes mellitus (DM), yet pharmacological treatments for diabetes-related erectile dysfunction (DMED) continue to be inadequate in clinical settings. Our previous studies have indicated that there is a close correlation between ED and pyroptosis, but the specific mechanism remains unclear. In this study, we sought to explore the therapeutic effects of DMED through the modulation of NLRP3, aiming to elucidate its potential molecular mechanisms. The DMED rat model was established via intraperitoneal injection of streptozotocin. The rats were randomly assigned to the control group, the DMED group, the Yimusake group, the MCC950 (NLRP3 inhibitor) group, and the MCC950+Yimusake group. Erectile function of rats was observed by measuring intracavernosal pressure (ICP) and mean arterial pressure (MAP). HE staining was performed to observe the histopathological changes in penile; immunofluorescence was performed to measure the level of CD31 (Platelet endothelial cell adhesion molecule-1) in penile. Besides, immunohistochemistry, RT-qPCR and Western blot were performed to demonstrate the expression of NLRP3, caspase-1, IL-1β and eNOS. After treatment with the MCC950 and Yimusake, the number of blood sinusoids and small vessels significantly reduced in penile tissue; NLRP3, caspase-1, IL-1β proteins and mRNA expression decreased, eNOS protein and mRNA expression increased. Compare with the Y group and the MCC950 group, MCC950+Yimusake group had a more significant effect. MCC950 and Yimusake might potentially suppress pyroptosis in the penile tissue of DMED rats by modulating the NLRP3/caspase-1 pathway, thus enhancing erectile function. This discovery could offer a promising therapeutic approach for individuals with DMED.

Acute cerebral small vessel disease: Classification, mechanism, and therapeutic implications.

Acute cerebral small vessel disease: Classification, mechanism, and therapeutic implications.

Disparities in the diagnostic efficacy of radiomics models in predicting various degrees of cognitive impairment in patients with cerebral small vessel disease

BackgroundAim to validate the diagnostic efficacy of radiomics models for predicting various degrees of cognitive impairment in patients with cerebral small vessel disease (CSVD).MethodsParticipants were divided into mild cognitive impairment group (mild-CSVD group) and sever cognitive impairment group (sever-CSVD group) according to Montreal Cognitive Assessment (MoCA) performance, 98 gender-age-education matched subjects served as normal controls. Radiomic features were extracted from the segmented hippocampus using PyRadiomics. The feature preprocessing involved replacing missing values with the mean, applying stratified random sampling to allocate subjects into training (80%) and testing (20%) sets, ensuring balance among the three classes (normal controls, mild-CSVD group, and sever-CSVD group). A feature selection method was applied to identify discriminative radiomic features, with the optimal texture feature chosen for developing diagnostic models. Performance was evaluated in both the training and testing sets using receiver operating characteristic (ROC) curve analysis.ResultsThe radiomics model achieved an accuracy of 0.625, an AUC of 0.593, a sensitivity of 0.828, and a specificity of 0.316 in distinguishing mild-CSVD group from normal controls. When distinguishing mild-CSVD group from sever-CSVD group, the radiomics model reached an accuracy of 0.683, an AUC of 0.660, a sensitivity of 0.167, and a specificity of 0.897. Similarly, in distinguishing sever-CSVD group from normal controls, the radiomics model exhibited an accuracy of 0.781, an AUC of 0.818, a sensitivity of 0.538, and a specificity of 0.947.ConclusionRadiomics model based on hippocampal texture had disparities in the diagnostic efficacy of radiomics models in predicting various degrees of cognitive impairment in patients with CSVD.

Assessment of image-derived input functions from small vessels for patlak parametric imaging using total-body PET/CT.

The image-derived input function (IDIF) from the descending aorta has demonstrated performance comparable to arterial blood sampling while avoiding its invasive nature in parametric imaging. However, in conventional PET, large vessels may not always be within the imaging field of view (FOV). This study aims to evaluate the efficacy of dynamic parametric Ki imaging using image-derived input functions (IDIFs) extracted from various arteries, facilitated by total-body PET/CT. Twenty-three participants underwent a 60-minute total-body [18F]FDG PET scan. Data from each subject were used to reconstruct both total-body PET images and short-axis field-of-view PET images at different bed positions, each with a 25cm axial field-of-view (AFOV). Partial volume correction (PVC) was performed using the blurred Van Cittert iterative deconvolution. IDIFs extracted from the descending aorta, carotid artery, abdominal aorta, and iliac artery were employed for Patlak analysis. The resulting Ki images were compared using quantification indicators and subjective assessment. Linear regression analysis was conducted to examine the correlation of Ki values among IDIFs in normal organ and lesion regions of interest (ROIs). High similarities were observed in Ki images derived from the IDIFs from the descending aorta and other arteries, with a median structural similarity index measure (SSIM) above 0.98 and a median peak signal-to-noise ratio (PSNR) above 37dB. Linear regression analysis revealed strong correlations in Ki values (r² > 0.88) between the descending aorta and the three alternative vessels, with slopes of the linear fits close to 1. No significant difference in lesion detectability among IDIFs was found, as assessed visually and using metrics such as tumor-to-background ratio (TBR) and contrast-to-noise ratio (CNR) (P < 0.05). IDIFs from smaller vessels can reliably reconstruct parametric Ki images without compromising lesion detectability, providing clinically relevant information.

Optimization of mechanical properties of small diameter artificial blood vessels based on alginate/chitosan/gelatin

Due to the rise in cardiovascular disease and the problem of autologous transplant limitation, the emergence of 3D bioprinted blood vessels using natural polymer materials as ink is becoming increasingly important in the field of small-diameter artificial blood vessels (φ ≤ 6 mm). In this paper, gelatin was firstly adopted to explore alginate/chitosan composite hydrogel properties and solve the current issues of poor mechanical performance and suboptimal printability of small-diameter blood vessels, which indicated that the modification caused a 17.7 % increase in compressive strength and a 63.2 % enhancement in tensile properties. The material microstructure evaluation showed that the samples with gelatin(4 %) presented the excellent water absorption rate(>90 %) significantly increasing their porosities. A self-developed 3D bioprinter was utilized to clarify the controllable mechanism of small-diameter artificial blood vessel, which has superior performance and excellent printability. This study provides a new reference solution to the current challenges in the bio-ink performance and printability of small-diameter artificial blood vessels.

RP squeeze U-SegNet model for lesion segmentation and optimization enabled ShuffleNet based multi-level severity diabetic retinopathy classification

ABSTRACT In Diabetic Retinopathy (DR), the retina is harmed due to the high blood pressure in small blood vessels. Manual screening is time-consuming, which can be overcome by using automated techniques. Hence, this paper proposed a new method for classifying the multi-level severity of DR. Initially, the input fundus image is pre-processed by Non-local means Denoising (NLMD). Then, lesion segmentation is carried out by the Recurrent Prototypical-squeeze U-SegNet (RP-squeeze U-SegNet). Next, feature extraction is effectuated to mine image-level features. DR is categorized as abnormal or normal by ShuffleNet and it is tuned by Fractional War Royale Optimization (FrWRO), and later, if DR is detected, severity classification is performed. Furthermore, the FrWRO-SqueezeNet obtained the maximum performance with sensitivity of 97%, accuracy of 93.8%, specificity of 95.1%, precision of 91.8%, and F-Measure of 94.3%. The devised scheme accurately visualizes abnormal regions in the fundus images. Also, it has the ability to identify the severity levels of DR effectively, which avoids the progression risk to vision loss and proliferative disease.

Early depiction of anterior spinal arteries and veins in André du Laurens’s Historia anatomica humani corporis (1600)

ABSTRACT Scholars usually consider the Historia anatomica corporis humani, published in 1600 by André du Laurens, as an obsolete defense of Galenic principles against the novelty of Vesalian material. Although du Laurens’s book plagiarized many illustrations from Vesalius’s De humani corporis fabrica (1543), critics such as Choulant insisted that the Historia’s iconography had “no particular anatomical or artistic value.” However, four of the Historia’s engravings appear to be original. One of these, the Tabula hæc veram spinalis medullae et nervorum ab ea prodeuntium effigiem exprimit, is now famous for depicting the intradural spinal nerves as a horsetail, leading to the addition of the term cauda equina to the anatomical lexicon. A less flamboyant figure from the same plate shows small blood vessels coursing over the surface of the cervical spinal cord. This drawing may be the first published depiction of anterior spinal arteries and veins.

Location and Extent of Paravascular Nerve Fiber Layer Clefts in Eyes with Epiretinal Membranes.

Purpose: The clinical use of en face optical coherence tomography (OCT) has revealed nerve fiber layer clefts in the retinal nerve fibers in eyes with macula-centered epiretinal membranes (ERMs). The purpose of this study is to describe the location and the extent of retinal nerve fiber layer (RNFL) clefts in eyes with symptomatic ERMs. Methods: We conducted a retrospective review of 17 individual eyes in 17 patients with symptomatic ERMs and a control group of 10 healthy eyes from 10 subjects who had been examined for unrelated causes. The examinations performed included best-corrected visual acuity, rebound tonometry, fundus photography, structural OCT and angiographic OCT (OCTA) made in the form of 12 × 12 mm angiographic volume scans. Results: Hyporeflective RNFL clefts, seen in 14 out of 17 eyes with ERMs, were sharply demarcated in the en face presentation of slabs extending from the internal limiting membrane through the RNFL or including only the latter. The clefts were capillary-free on OCTA scans and formed depressions of the retinal surface. Most of the clefts were adjacent to and followed the course of the retinal trunk vessels, but clefts were also seen along smaller macular vessels and beyond the retinal vascular arcades. Conclusions: Paravascular RNFL clefts can be observed beyond the vascular arcades and adjacent to small vessels on OCTA block scan data. This suggests that the direction and magnitude of tractional displacement of the inner retina in eyes with epimacular membranes can extend beyond the vascular arcades and add to an improved analysis of abnormal fundus findings.