University Hospital Frankfurt, Department of Diagnostic and Interventional Radiology, Frankfurt, Germany.
University Hospital Frankfurt, Department of Diagnostic and Interventional Radiology, Frankfurt, Germany.
Eur J Radiol. 2020 Nov;132:109276. doi: 10.1016/j.ejrad.2020.109276. Epub 2020 Sep 11.
To analyze the impact of tube potential and iodine concentration on the visibility of calcified plaques in coronary computed tomography angiography (cCTA).
METHODS & MATERIALS: 164 consecutive patients (65.9 % men and a mean age of 57.1 ± 11.3 years) with suspected coronary artery disease underwent calcium scoring (CaSc) scan followed by cCTA with topogram-based automated tube voltage selection (70 kV, 80 kV, 90 kV, 100 kV or 120 kV). In 127 Patients (HC), we injected 50 mL of contrast material (CM) with a concentration of 400 mg iodine per ml and in 37 patients (LC) 50 mL iodine concentration of 280 mg/mL. Sensitivity of cCTA for detecting calcified plaques was calculated with CaSc serving as gold standard. Density of CM enhanced coronary vessels and calcified plaques were quantified by region-of-interest (ROI) measurements in unenhanced and cCTA image series.
Overall sensitivity of cCTA to detect calcified plaques was significantly higher using LC compared to HC (79 % vs. 73 %; p = 0.0035). The impact of LC was impressive at 70 kV with an improved sensitivity of 70 % vs. 57.1 % in HC (p = 0.0082). Furthermore, density values of HC enhanced coronary vessels exceeded those of calcified plaques, especially at low kV levels. In LC, except for the 70 kV setting, higher density values were shown for calculi than enhanced vessels.
Low kV cCTA in routine using highly concentrated CM leads to reduced calcified plaque perceptibility and hence potentially underestimation of stenosis. Thus, low kV cCTA using CM with lower iodine concentration is necessary. In addition, a dose reduction up to 77.7 % can also be benefited.
分析管电压和碘浓度对冠状动脉 CT 血管造影（cCTA）中钙化斑块可见度的影响。
164 例连续疑似冠心病患者（65.9%为男性，平均年龄 57.1±11.3 岁）行钙评分（CaSc）扫描，随后行基于拓扑的自动管电压选择（70kV、80kV、90kV、100kV 或 120kV）的 cCTA。在 127 例患者（HC）中，我们注射了 50ml 浓度为 400mg 碘/ml 的造影剂（CM），在 37 例患者（LC）中注射了 50ml 浓度为 280mg/ml 的碘。以 CaSc 为金标准，计算 cCTA 检测钙化斑块的敏感度。通过 ROI 测量，在未增强和 cCTA 图像系列中量化 CM 增强的冠状动脉和钙化斑块的密度。
使用 LC 时，cCTA 检测钙化斑块的总体敏感度明显高于 HC（79%比 73%；p=0.0035）。在 70kV 时，LC 的影响令人印象深刻，HC 的敏感度从 57.1%提高到 70%（p=0.0082）。此外，HC 增强的冠状动脉密度值高于钙化斑块，尤其是在低 kV 水平。在 LC 中，除了 70kV 外，结石的密度值高于增强的血管。
在常规使用高浓度 CM 的低 kV cCTA 中，钙化斑块的可察觉性降低，从而可能低估狭窄程度。因此，有必要使用 CM 进行低 kV cCTA，碘浓度较低。此外，还可以受益于剂量减少 77.7%。
