Ex Vivo Evaluation Of Dual-source CT Characterizing And Quantifying The Coronary Atherosclerotic Plaques

Objective To evaluate the ability of dual-source CT characterizing and quantifying the coronary atherosclerotic plaques compared to histopathology, providing anatomic and histopathologic reference for imageology diagnosis and clinical treatment.Methods 14 hearts were obtained from formalin fixed adult cadavers. Remove the pericardium, cut the trachea, esophagus and burdensome objects and the main vessels connected to the heart. Make the appearance of hearts clean and tidy, and the surface maker was well displayed. The major coronary arteries were dissected free from 14 autopsy hearts and the distal and branches were ligated. Coronary arteries were injected with contrast agent from coronary artery ostium and were scanned by contrasted-enhanced DSCT with an axial slice thickness of 0.6mm. According to the proportion of calcifications and CT attenuation values, plaques were classified as calcified, non-calcified and mixed. Multi-planar reformation(MPR), maximum intensity projection(MIP), volume-rendered technique(VRT) and cross-sectional images were reconstructed to observe and quantify coronary artery stenosis. After contrast-enhanced CT scanning, standard pathological sectioning of the coronary arteries was performed. Histopathological classification of atherosclerotic plaques and quantification of coronary artery stenosis were considered the standard of reference.Result Histopathology found 105 plaques,88 plaques were detected by DSCT,The sensitivity of DSCT for detecting all plaques was 83.8%(88/105), for detecting early type(I-III) and advanced type(IV-Vc)plaques were 20% and 90.5%, respectively, for detecting III type 、IV type、Va type、Vb type and Vc type plaques were 40%、87.5% 、80% 、92.7% and 87.5%, respectively. Calcified plaques mainly correspond with Vb type plaques. Mixed plaques mainly correspond with IV type、Va type、Vb type and Vc type plaques. Non-calcified plaques mainly correspond with III type、 IV type、Va type and Vc type plaques. The mean CT attenuation values of calcified, mixed and non-calcified(402.2±104.3 HU, 172.7±48.6 HU and 48.9±33.2 HU; respectively; p<0.05) were significantly different. The mean CT attenuation values of IV type、Va typ and Vc type plaques(60.9±48.7HU, 61.4±43.0HU and 80.3±53.8HU, respectively; P>0.05)were not significantly different. The mean CT attenuation values of Vb type(380.4±116.9 HU;P<0.05) were significantly higer than other types. There was no significant difference between the mean attenuation values of predominantly lipid-rich and fibrous-rich plaques(61.1±14.5 HU and 80.3±53.8HU, respectively; P>0.05). Compared with histopathology, for segment-based analysis, the sensitivity, specificity, positive and negative predictive value of DSCT for detecting obstructive coronary artery disease were 94.1%、95.7%、88.8% and 97.8%,respectively. DSCT was well correlated with histopathology for quantifying the coronary stenosis of all plaques(r=0.9, p<0.05). DSCT was well correlated with histopathology for quantifying the coronary stenosis of calcified, mixed and non-calcified plaques(r=0.9、r=0.99 and r=0.9, respectively; p<0.05). Compared with histopathology, DSCT systematically underestimated the coronary stenosis of non-calcified plaques(mean difference- 6.2% ±1.6%, p<0.05) and systematically overestimated the coronary stenosis of calcified plaques(mean difference 6.4%±6.8%, p<0.05), while DSCT has a high accuracy for quantifying coronary stenosis of mixed plaques(mean difference 1.1% ±2.2%, p= 0.1). DSCT was well correlated with histopathology for quantifying the coronary stenosis of mild, moderate, and severe calcification(r=0.9 、 r=0.9 and r=0.8, respectively; p<0.05). DSCT systematically overestimated the coronary stenosis of mild,moderate and severe calcification(mean difference 3.2% ±2.0%, 4.9% ±4.7% and 14.7% ±8.2%, respectively; p<0.05)compared with histopathology, while DSCT has a high accuracy for quantifying coronary stenosis of mild and moderate calcification compared with severe calcification.Conclusion 1. Dual-source CT contrast enhancement scanning can detect different types of coronary atherosclerotic plaques, especially for advanced types(IV-Vc) plaques. 2. The plaque mean CT attenuation values can represent predominant plaque component which were well consistent with histopathologic classification.To some extent, DSCT is able to distinguish the advanced types plaques. 3. DSCT has a high diagnostic accuracy for obstructive coronary artery disease. This will provide important reference for the application of DSCT in clinical practice. 4. DSCT was well correlated with histopathology for quantifying coronary stenosis of coronary atherosclerotic plaques, but DSCT has different diagnostic accurancy for coronary artery stenosis which caused by different types plques, this will provide important reference information for clinicians in diagnosing coronary artey disease and drawing up interventional therapy for coronary artery disease. 5. DSCT was well correlated with histopathology for quantifying coronary artery stenosis which caused by different types of calcified plaques, DSCT has a high accuracy for quantifying coronary stenosis of mild and moderate calcification.