Department of Diagnostic and Interventional Radiology, University of Tübingen, Tübingen 72076, Germany.
AJR Am J Roentgenol. 2010 Jun;194(6):1590-5. doi: 10.2214/AJR.09.3550.
Dual-energy CT has the potential to automatically remove calcified plaques from angiographic data sets. The objective of this study is to compare the accuracy of visual grading of stenoses after plaque removal with visual grading in standard reconstructions. Digital subtraction angiography (DSA) was used as a reference standard.
Twenty-five patients underwent dual-energy CT (140 kV and 80 mAs; 80 kV and 234 mAs) angiography and DSA. Plaque and bone removal was performed. Twenty-nine calcified stenoses were quantified using standard reconstructions, plaque and bone removal maximum intensity projections after plaque and bone removal, and DSA images, according to the North American Symptomatic Carotid Endarterectomy Trial criteria. The accuracy of the detection of relevant stenoses (> 70%) and occlusions was assessed. Correlation coefficients of the grades of stenoses with DSA were calculated. The influence of vessel enhancement on the accuracy of plaque removal was analyzed.
The average postprocessing time was 45 seconds. After plaque removal, all 25 relevant and four nonrelevant stenoses were correctly detected. Six relevant stenoses were overestimated as complete occlusions. With the standard reconstructions, two nonrelevant stenoses were overestimated as relevant. Correlation coefficients (r(2)) for the grading of stenoses after plaque removal and with standard reconstructions versus DSA were 0.7694 and 0.4329, respectively. Vessel contrast enhancement correlated weakly (r(2) = 0.2072) with the accuracy of plaque removal.
Dual-energy CT with plaque removal automatically delivers CT luminograms with a high sensitivity for the detection of relevant stenoses and a higher correlation to DSA than standard reconstructions but frequently leads to an overestimation of high-grade stenoses as occlusions. Thus, dual-energy CT plaque and bone removal should be used complementary to standard reconstructions, and not exclusively.
双能 CT 有可能自动从血管造影数据集去除钙化斑块。本研究的目的是比较斑块去除后狭窄程度的视觉评分与标准重建的视觉评分的准确性。数字减影血管造影（DSA）被用作参考标准。
25 例患者接受了双能 CT（140kV 和 80mAs；80kV 和 234mAs）血管造影和 DSA。进行了斑块和骨去除。根据北美症状性颈动脉内膜切除术试验标准，使用标准重建、斑块和骨去除后最大强度投影以及 DSA 图像对 29 个钙化狭窄部位进行定量评估。评估相关狭窄（>70%）和闭塞的检测准确性。计算狭窄程度与 DSA 的相关系数。分析血管增强对斑块去除准确性的影响。
平均后处理时间为 45 秒。在斑块去除后，所有 25 个相关狭窄和 4 个不相关狭窄均被正确检测到。6 个相关狭窄被高估为完全闭塞。使用标准重建，两个不相关狭窄被高估为相关狭窄。斑块去除和标准重建后狭窄程度的分级与 DSA 的相关系数（r²）分别为 0.7694 和 0.4329。血管对比增强与斑块去除的准确性呈弱相关（r²=0.2072）。
双能 CT 斑块去除可自动提供 CT 血管造影图，对相关狭窄的检测具有较高的敏感性，与 DSA 的相关性高于标准重建，但经常导致高级别狭窄被高估为闭塞。因此，双能 CT 斑块和骨去除应与标准重建互补使用，而不是单独使用。
