Objective of this article – to evaluate possibilities to visualize cardiac visceral adipose tissue by echocardiography, computed tomography (CT), and magnetic resonanse imaging (MRI) and to systematize data on its physiological and pathological roles. To achieve this goal, the authors analyzed relevant Russian and foreign sources of literature in the scientific libraries eLIBRARY and PubMed, by using the keywords: “pericardial fat”, “epicardial fat”, “visceral fat of the heart”, “epicardial adipose tissue”, “pericardial adipose tissue”, and “adipocytokine”. Actual data as of November 2018 were collected. The review presents up-to-date data on the physiological and pathophysiological roles of cytokines secreted by pericardial adipose tissue, as well as on correlations and possible theories of the relationship between the volumes of pericardial adipose tissue and the development of coronary heart disease, atrial fibrillation, and metabolic syndrome. According to echocardiography, epicardial adipose tissue thickness is a reliable predictor for the presence of high-risk atherosclerotic plaques in the coronary arteries. Adipose tissue volume can be measured with high accuracy using CT (manual, semi-automatic, and automatic methods).A number of studies prove that MRI can be used for assigned tasks. The current notion of the role of these adipose depots can potentially be used in assessing the risk of cardiovascular diseases. The literature review presented confirms that visceral adipose tissue of the heart has a direct effect on the myocardium and coronary arteries and can be quantified using echocardiography, CT and MRI.
Rationale. Quantitative CT (QCT) bone densitometry with asynchronous calibration not require a phantom during the scan procedure. Based on calibration data it converts X-ray density in HU to bone mineral density (BMD). Given the large number of CT studies performed on patients at risk of osteoporosis, there is a need for a hands-on method capable of assessing BMD in a short period of time without tailored software or protocols.Goal. To develop a method for QCT bone densitometry using an PHK (PHantom Kalium), to compare the volume BMD measurements with the QCT data with asynchronous calibration provided by software from a reputable developer.Methods. The studies were performed at 64-slice CT unit with body scanning parameters. The BMD was measured using two techniques: 1) QCT with asynchronous calibration using software from a reputable developer; 2) QCT using a PHK phantom (QCT-PHK). For convert the HU to BMD values, we scanned the PHK phantom and calculate correction factor. Phantom contains “vertebrae” filled with potassium hydrogen phosphate in different concentrations. In both methods, the BMD values measured for LI–II, and sometimes for ThXII, LIII.Results. The study enrolled 65 subjects (11 male and 54 female patients); median age 69.0 years. A comparison of the vertebrae BMD measured by QCT and QCT-PHK revealed a significant linear Pearson correlation r = 0.977 (p < 0.05). The Bland–Altman analysis demonstrated a lack of relationship between the difference in measurements and the average BMD and a systematic BMD; bias of +4.50 mg/ml in QCT vs. QCT-PHK. Differences in the division into groups osteoporosis / osteopenia / norm according to the ACR criteria for the two methods were not significant.Conclusion. The developed asynchronous QCT-PHK method measure BMD comparable to the widely used QCT with asynchronous calibration. This method can be used for opportunistic screening for osteoporosis.
Purpose of the study — to assess the accuracy of dual energy x-ray absorptiometry (DXA ) for measurements of mineral bone density, bone mineral content, area of selected spine zone of examination as well as impact of subcutaneous fat layer and correction of auto-segmenting of the spine on the mentioned parameters. Material and Methods. The study was performed on iDXA scanner using the designed phantom DMA PP2 of the lumber spine with inlays to simulate subcutaneous fat (SF). To ensure correct assessment of measurements (precision and accuracy) the authors performed fivefold repeated scanning. Two modifications of the phantom were used, with and without SF inlays, as well as two methods for selection of spine range for examination – automatic and correction of autosegmentation. Results. Scanning of the phantom without SF inlays demonstrated a systematic understated values of bone mineral density (BMD) and bone mineral content (BMC) along the full measured interval: mean relative error of BMD for L1-L4 interval was 10.62% with automatic segmentation and 7.43% — with correction of autosegmentation. The least accuracy for BMD and BMC (1.53% and 0.90%, respectively) was observed during SF simulation and with correction of auto-segmentation of the spine. Analysis of variation coefficient for area of examined vertebrae, BMC and BMD demonstrated rather high precision of measurements, namely for BMD without SF in the L1-L4 interval amounted to 1.00% (auto-segmentation) and 0.56% (correction). Variation coefficient for scanning including SF inlays in the interval L1-L4 was 1.00% (auto-segmentation) and 0.68% (correction). Conclusion. The lowest level of accuracy was observed with the SFL object; in this case, the variation coefficient did not exceed 1% for all BMD interval. The mean value of the BMC accuracy also did not exceed 1% with the optimal scan parameters. The study proved the effectiveness of “RSK PK2” phantom when estimating the accuracy of BMD and BMC on iDXA scanner.
The article presents an overview of qualitative and quantitative methods for coronary calcification assessment by computed tomography (CT). Coronary calcium is one of the well-known predictors of coronary artery disease and its complications. Coronary artery calcification is a common significant finding on routine and low-dose CT. In the review, the Coronary Artery Calcium Data and Reporting System (CAC-DRS) and the Coronary Artery Disease Reporting and Data System (CAD-RADS) are analyzed. Recommendations are given for the further management of patients with stable or acute chest pain in accordance with the CAD-RADS classification. The main aim of CAD-RADS is the standardization of accounting for coronary computed tomography angiography (CCTA) results for facilitating the interpretation by clinicians and subsequent management of patients. Such an approach should lead to an increase of healthcare quality.
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