Department of Diagnostic and Interventional Radiology, Clinic of the Goethe University, Haus 23C UG, Theodor-Stern-Kai 7, Frankfurt am Main 60590, Germany.
AJR Am J Roentgenol. 2010 Sep;195(3):639-46. doi: 10.2214/AJR.09.3849.
The purpose of this article is to compare the performance of dual-energy CT with that of 3-T MRI with late enhancement for the detection of chronic myocardial infarction during first-pass coronary CT angiography (CTA).
Thirty-six patients underwent coronary CTA for the assessment of coronary bypass graft patency on a first-generation dual-source CT scanner in dual-energy mode. Gray-scale images (100 kV, 140 kV, and blended virtual 120 kV) were assessed for areas of hypodense myocardium during the arterial phase. In addition, a color-coded map of myocardial iodine distribution was calculated from the dual-energy data for perfusion analysis. Dual-energy CT data were compared with data from 3-T MRI with late enhancement, which served as the reference standard for scar detection using the American Heart Association's 17-segment model of the left ventricle.
One hundred one (17%) of 612 myocardial segments in 22 (61%) of 36 patients showed late enhancement on MRI. Although myocardial iodine mapping was prone to artifacts, mostly arising from sternal wires (70% sensitivity), 100-kV gray-scale images showed the highest sensitivity (80%) for the detection of myocardial scar. Blended virtual 120-kV images with lower noise and higher resolution had the best diagnostic accuracy (77% sensitivity, 97% specificity, 85% positive predictive value, 96% negative predictive value, and 94% accuracy).
Detection of chronic myocardial infarction on color-coded iodine distribution analysis with first-generation dual-energy CT is impeded by thoracic metallic devices. This group of patients benefits more from adequate blending of high- and low-kilovoltage gray-scale images. Further technical improvements are desirable to lower artifact burden and improve sensitivity on myocardial iodine distribution mapping.
本文旨在比较双能 CT 与 3-T MRI 延迟增强技术在首次通过式冠状动脉 CT 血管造影（CTA）中对慢性心肌梗死的检测性能。
36 例患者在第一代双源 CT 扫描仪上进行冠状动脉 CTA，以评估冠状动脉旁路移植血管通畅性。在动脉期，对灰度图像（100kV、140kV 和混合虚拟 120kV）进行低衰减心肌区域评估。此外，从双能量数据中计算出心肌碘分布的彩色编码图，用于灌注分析。将双能 CT 数据与 3-T MRI 延迟增强数据进行比较，后者作为使用美国心脏协会左心室 17 节段模型检测瘢痕的参考标准。
22 例（61%）患者的 612 个心肌节段中，有 101 个（17%）在 MRI 上显示延迟增强。尽管心肌碘映射易受伪影影响，主要来自胸骨金属丝（70%的敏感性），100kV 灰度图像对心肌瘢痕的检测具有最高的敏感性（80%）。噪声较低、分辨率较高的混合虚拟 120kV 图像具有最佳的诊断准确性（77%的敏感性、97%的特异性、85%的阳性预测值、96%的阴性预测值和 94%的准确性）。
第一代双能 CT 彩色碘分布分析检测慢性心肌梗死受胸部金属设备的影响。这组患者从高、低千伏灰度图像的充分混合中获益更多。需要进一步的技术改进来降低伪影负担并提高心肌碘分布映射的敏感性。
