Detection Of Vascular Lesions Research Articles

A Method for Diagnosing Diabetic Retinopathy Based on Ocular Fundus Imaging

Introduction. Diabetic retinopathy is a complication of diabetes mellitus caused by high blood sugar levels damaging the retina. Diabetic retinopathy leads to changes in ocular blood vessels and the appearance of solid exudates and microaneurysms. When diagnosed and treated in the late stages, this disease can cause blindness. The most common diagnostic method for diabetic retinopathy is based on ocular fundus imaging. However, the background interference and low contrast of such images significantly hinders the timely detection of vascular lesions. Therefore, the development of a method for detecting signs of diabetic retinopathy, particularly in its early stages, presents a relevant research task.Aim. Development of a method for diagnosing diabetic retinopathy based on an analysis of ocular fundus images using the decision-tree approach.Materials and methods. Methods based on image segmentation with identifying characteristic features and their binary classification were used. A verified database was used to access the accuracy of the proposed method for detecting diabetic retinopathy.Results. A method for detecting signs of diabetic retinopathy was developed, which includes the segmentation of vessels, exudates and microaneurysms based on digital processing of ocular vascular images using binary classification. The developed method showed a high level of diagnostic accuracy. Thus, the sensitivity, specificity and accuracy of diabetic retinopathy detection comprised 87.14, 88.50 and 87.81 %, respectively.Conclusion. The developed method allows diabetic retinopathy to be diagnosed with sufficiently high accuracy. The method can also be used for supporting decision making when managing patients with diabetic retinopathy.

S1341 Development of a Convolutional Neural Network for the Detection of Vascular Lesions in Double-Balloon Enteroscopy: A Proof-of-Concept Study

S1341 Development of a Convolutional Neural Network for the Detection of Vascular Lesions in Double-Balloon Enteroscopy: A Proof-of-Concept Study

Long-term exposure to high glucose increases the content of several exocytotic proteins and of vesicular GABA transporter in cultured retinal neural cells

Diabetic retinopathy is a leading cause of vision loss and blindness. Increasing evidence has shown that the neuronal components of the retina are affected even before the detection of vascular lesions. Hyperglycemia is considered the main pathogenic factor for the development of diabetic complications. Nevertheless, other factors like neuroinflammation, might also contribute for neural changes. To clarify whether hyperglycemia can be the main trigger of synaptic changes, we evaluated whether prolonged elevated glucose per se, mimicking chronic hyperglycemia, is able to change the content and distribution of several exocytotic proteins and vesicular glutamate and GABA transporters in retinal neurons. Moreover, we also tested the hypothesis that an inflammatory stimulus (interleukin-1β) could exacerbate the effects induced by exposure to elevated glucose, contributing for changes in synaptic proteins in retinal neurons.Rat retinal neural cells were cultured for 9 days. Cells were exposed to elevated d-glucose (30mM) or d-mannitol (osmotic control), for 7 days, or were exposed to interleukin-1β (10ng/ml) or LPS (1μg/ml) for 24h. The protein content and distribution of SNARE proteins (SNAP-25, syntaxin-1, VAMP-2), synapsin-1, synaptotagmin-1, rabphilin 3a, VGluT-1 and VGAT, were evaluated by western blotting and immunocytochemistry. The protein content and immunoreactivity of syntaxin-1, synapsin-1, rabphilin 3a and VGAT increased in retinal neural cells exposed to high glucose. No changes were detected when cells were exposed to interleukin-1β, LPS or mannitol per se. Particularly, exposure to interleukin-1β for 24h did not exacerbate the effect of high glucose on the content and immunoreactivity of exocytotic proteins, suggesting the primordial role of hyperglycemia for neuronal changes. In summary, prolonged exposure to elevated glucose alters the total content of several proteins involved in exocytosis, suggesting that hyperglycemia per se is a fundamental factor for neuronal changes caused by diabetes.

Detection of retinal lesions in diabetic retinopathy: comparative evaluation of 7-field digital color photography versus red-free photography

Red-free light allows better detection of vascular lesions as this wavelength is absorbed by hemoglobin; however, the current gold standard for the detection and grading of diabetic retinopathy remains 7-field color fundus photography. The goal of this study was to compare the ability of 7-field fundus photography using red-free light to detect retinopathy lesions with corresponding images captured using standard 7-field color photography. Non-stereoscopic standard 7-field 30° digital color fundus photography and 7-field 30° digital red-free fundus photography were performed in 200 eyes of 103 patients with various grades of diabetic retinopathy ranging from mild to moderate non-proliferative diabetic retinopathy to proliferative diabetic retinopathy. The color images (n=1,400) were studied with corresponding red-free images (n=1,400) by one retina consultant (PV) and two senior residents training in retina. The various retinal lesions [microaneurysms, hemorrhages, hard exudates, soft exudates, intra-retinal microvascular anomalies (IRMA), neovascularization of the retina elsewhere (NVE), and neovascularization of the disc (NVD)] detected by all three observers in each of the photographs were noted followed by determination of agreement scores using κ values (range 0-1). Kappa coefficient was categorized as poor (≤0), slight (0.01-0.20), fair (0.2 -0.40), moderate (0.41-0.60), substantial (0.61-0.80), and almost perfect (0.81-1). The number of lesions detected by red-free images alone was higher for all observers and all abnormalities except hard exudates. Detection of IRMA was especially higher for all observers with red-free images. Between image pairs, there was substantial agreement for detection of hard exudates (average κ=0.62, range 0.60-0.65) and moderate agreement for detection of hemorrhages (average κ=0.52, range 0.45-0.58), soft exudates (average κ=0.51, range 0.42-0.61), NVE (average κ=0.47, range 0.39-0.53), and NVD (average κ=0.51, range 0.45-0.54). Fair agreement was noted for detection of microaneurysms (average κ=0.29, range 0.20-0.39) and IRMA (average κ=0.23, range 0.23-0.24). Inter-observer agreement with color images was substantial for hemorrhages (average κ=0.72), soft exudates (average κ=0.65), and NVD (average κ=0.65); moderate for microaneurysms (average κ=0.42), NVE (average κ=0.44), and hard exudates (average κ=0.59) and fair for IRMA (average κ=0.21). Inter-observer agreement with red-free images was substantial for hard exudates (average κ=0.63) and moderate for detection of hemorrhages (average κ=0.56), SE (average κ=0.60), IRMA (average κ=0.50), NVE (average κ=0.44), and NVD (average κ=0.45). Digital red-free photography has a higher level of detection ability for all retinal lesions of diabetic retinopathy. More advanced grades of retinopathy are likely to be detected earlier with red-free imaging because of its better ability to detect IRMA, NVE, and NVD. Red-free monochromatic imaging of the retina is a more effective and less costly alternative for detection of vision-threatening diabetic retinopathy.

Giant cell arteritis. Part I. Terminology, classification, clinical manifestations, diagnosis

Giant cell arteritis (GCA) is a vasculitis affecting mainly large and medium-sized arteries, which the classification of systemic vasculitides refers to as those mainly involving the large vessels. GCA is typified by the involvement of extracranial aortic branches and intracranial vessels, the aorta and its large vessels are being affected most frequently. The paper considers the terminology, classification, prevalence, major pathogenic mechanisms, and morphology of GCA. A broad spectrum of its clinical subtypes is due to target vessel stenosis caused by intimal hyperplasia. In 40% of cases, GCA is shown to be accompanied by polymyalgia rheumatica that may either precede or manifest simultaneously with GCA, or follow this disease. The menacing complications of GCA may be visual loss or ischemic strokes at various sites depending on the location of the occluded vessel. Along with the gold standard verification of the diagnosis of GCA, namely temporal artery biopsy, the author indicates other (noninvasive) methods for detection of vascular lesions: color Doppler ultrasonography of the temporal arteries, fluorescein angiography of the retina, mag-netic resonance angiography, magnetic resonance imaging, and computed tomography to rule out aortic aneurysm. Dynamic 18F positron emission tomography is demonstrated to play a role in the evaluation of therapeutic effectiveness.

Minimally invasive post-mortem CT-angiography in a case involving a gunshot wound

Non-contrast post-mortem computed tomography (pm-CT) is useful in the evaluation of bony pathologies, whereas minimally invasive pm-CT-angiography allows for the detection of subtle vascular lesions. We present a case of an accidentally self-inflicted fatal bullet wound to the chest where pm-CT-angiography revealed a small laceration of the anterior interventricular branch of the left coronary artery and a tiny disruption of the right ventricle with pericardial and pleural effusion. Subsequent autopsy confirmed our radiological findings. Post-mortem CT-angiography has a great potential for the detection of vascular lesions and can be considered equivalent to autopsy for selected cases in forensic medicine.

Evaluation of Measures of Technical Image Quality for Intracranial Magnetic Resonance Angiography

We evaluate three measures of technical image quality for intracranial magnetic resonance angiography (MRA): (1) a two-alternative forced choice (2AFC) evaluation of vessel visibility, (2) vessel-to-background signal-difference-to-noise ratio (SDNR), and (3) observer ranking of the fidelity of vessel morphology compared to that in a gold standard image. The gold standard used for both the 2AFC and ranking measures is intraarterial catheter angiography. These measures are applied to healthy arterial segments. The 2AFC and SDNR measures directly evaluate the visibility of artery segments for which the existence is known from the gold standard images. We argue that (1) 2AFC evaluates the carrier signals on which any vascular disease process is modulated and provides an upper bound on the detectibility of vascular lesions, (2) SDNR is a predictor of 2AFC, and (3) ranking may be used to predict the relative performance of techniques in the detection of vascular lesions.

Radioisotope generators for short-lived positron emitters applicable to positron emission tomography

Radioisotope generators provide short-lived positron emitters for positron emission tomography (PET) without the need for an on-site cyclotron. These generators consist of a long-lived parent radionuclide, generally produced on an accelerator, from which the short-lived daughter radionuclide is separated and used as needed. Generators developed and applied to PET studies include 288 d 68Ge for 68 min 68Ga, 25 d 82Sr for 76 s 82Rb and 20.1 h 122Xe for 3.6 min 122I. These radiotracers have been used for the assessment of myocardial and brain blood flow in patient studies. Additionally, 82Rb has been used to determine the breakdown in the blood brain barrier in brain tumor patients who have undergone radiation therapy. When used in conjunction with 18F-fluorodeoxylucose produced on a regional cyclotron for the measurement of glucose utilization in brain tumors, differential diagnosis can be made between tumor regrowth and radiation therapy necrosis. Other possible applications include the detection of vascular lesions with 68Ga labeled platelets or porphyrins.