Feasibility of using intravascular loopless monopole antenna to image atherosclerotic plaque in a porcine model with 3.0 T magnetic resonance imaging / 中华心血管病杂志

<p><b>OBJECTIVE</b>To investigate the feasibility of using intravascular loopless monopole antenna (ILMA) to image atherosclerosis plaque in a porcine model with 3.0T magnetic resonance imaging (MRI).</p><p><b>METHODS</b>Atherosclerosis model was established by feeding high fat diet combined with balloon catheter injury to the endothelium in 6 pigs. After 3 months, animals underwent MRI and ILMA examination. The ILMA was invasively inserted to the distal part of abdominal vein and bilateral common iliac veins. MR sequences including T1 weighted imaging (T1WI), T2WI were obtained. MR image data were transferred to post-processing station. Luminal border and external elastic membrane of the vessel were reconstructed based on the MR images. After co-register these images, vessel area, lumen area, vessel wall area and plaque burden in the same lesions imaged by different modality were calculated and compared. Finally, all animals were scarified and hematoxylin eosin (HE) staining was performed in the targeted vessels. Diagnostic accuracy of MR in delineating vessel wall and detecting plaque were analyzed and calculated by comparing with pathological results.</p><p><b>RESULTS</b>The atherosclerotic model was successfully established in all 6 pigs. Good agreement of delineating vessel area, lumen area vessel, wall area and plaque burden were found between MRI and pathology with r value of 0.98, 0.95, and 0.96, respectively (P < 0.001). Compared with pathological findings, the plaque component in corresponding area imaged by MR was as follows: sensitivity and specificity of detecting lipid plaque were 77% and 69%, kappa value was 0.75 ± 0.19 (P < 0.01); sensitivity and specificity on detecting fibrotic plaque were 78% and 73%, Κ value was 0.78 ± 0.18 (P < 0.01). The sensitivity and specificity of detecting calcified plaque were 100%. ILMA results showed that the average lumen area was 49.72 mm(2), average vessel area was 124.08 mm(2), and the average vessel wall area was 74.37 mm(2), ILMA slightly overestimated these indexes as compared with pathological results.</p><p><b>CONCLUSION</b>The results showed that ILMA could be used to image deepened artery and atherosclerotic plaque. Detected plaque size, vessel area, lumen area vessel, wall area, and plaque burden were comparable to pathological findings. It may thus provide an alternative method for detecting atherosclerotic plaque in future research work.</p>

Magnetic resonance imaging features of vulnerable plaques in an atherosclerotic rabbit model / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Noninvasive detection of vulnerable plaque has a significant implication for prevention and treatment of atherosclerotic diseases. The aim of this study is to investigate the difference between vulnerable plaques and stable plaques in magnetic resonance (MR) images.</p><p><b>METHODS</b>Atherosclerosis was induced in twenty male New Zealand white rabbits by high cholesterol diet and balloon injury of the abdominal aorta. After baseline (pre-triggering) MR imaging (MRI) scan, the rabbits underwent pharmaceutical triggering with Russell's viper venom and histamine to induce atherothrombosis, followed by another MRI scan 48 hours later (post-triggering). Rabbits were euthanized to obtain pathological and histological data. The results of MRI were compared with those of pathology and histology.</p><p><b>RESULTS</b>MRI showed that abdominal aorta of the rabbits had pathological change of atherosclerosis in different degrees. Seventy-five plaques were analysed, among which 14 had vulnerable thrombi and 61 stable. Thrombosis was identified in 7 of 11 rabbits by post-triggering MRI, the sensitivity and K value of MR in detection of vulnerable plaque was 71% and 0.803 (P < 0.05). MRI data significantly correlated with the histopathological data in fibrous cap thickness (r = 0.749) plaque area (r = 0.853), lipid core area (r = 0.900). Compared with stable plaques, vulnerable plaques had a significantly thinner fibrous cap ((0.58 ± 0.27) mm vs. (0.95 ± 0.22) mm), larger lipid core area ((7.56 ± 2.78) mm(2) vs. (3.29 ± 1.75) mm(2)), and a higher ratio of lipid core area/plaque area ((55 ± 16)% vs. (27 ± 17)%), but plaque area was comparable in two groups on MRI. The ratio of lipid core area/plaque area was a strong predictor of vulnerable plaques.</p><p><b>CONCLUSION</b>MRI could distinguish vulnerable plaques from stable plaques in a rabbit model of atherothrombosis and may thus be useful as a noninvasive modality for detection of vulnerable plaques in humans.</p>

Detection of atherosclerotic plaque progression in the abdominal aorta of rabbits with 3T magnetic resonance imaging / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>With features of high tissue contrast, MRI can be used for the qualitative and quantitative evaluation of atherosclerosis plaques. In this study we investigated the development of atherosclerosis plaque with high resolution 3T MRI in a rabbit model and compared the findings with the histopathological results.</p><p><b>METHOD</b>Twenty male New Zealand white rabbits were randomly allocated into an experimental group (n = 16) and a control group (n = 4). Atherosclerotic lesions were induced in the abdominal aorta by balloon injury and cholesterol feeding. Multiple sequences MRI examination (ToF, T1WI, T2WI, and CE T1WI) were performed at the 2nd, 3rd, and 4th months after aortic denudation. Vessel wall thickness, total vessel area, lumen area, and vessel wall area were recorded. Plaque components were analyzed using histological results as a standard reference.</p><p><b>RESULTS</b>Seventeen rabbits (14 in the experimental group and 3 in the control group) received all three MR examinations. Gradually, from 2 months to 4 months, vessel wall thickness and area in the experimental group increased significantly compared with the control group (P < 0.01). In the lumen area progressive stenosis was not found, even a slight dilation had developed in the experimental group. Lipid, fibrotic and calcified plaques can be differentiated by MR image. According to histological results, MRI had good performance in detection of lipid plaque.</p><p><b>CONCLUSION</b>MRI can be used to monitor progression of atherosclerosis and differentiate plaque components.</p>