Department of Radiology, Mie University Hospital, Tsu, Japan.
Department of Radiology, Mie University Hospital, Tsu, Japan.
J Cardiovasc Comput Tomogr. 2020 Nov-Dec;14(6):524-528. doi: 10.1016/j.jcct.2020.01.013. Epub 2020 Feb 15.
Myocardial extracellular volume fraction (ECV) derived from CT delayed enhancement (CTDE) may allow assessment of diffuse myocardial fibrosis. However, the amount of contrast medium required for ECV estimation has not been established. Since ECV estimation by CT is typically performed in combination with coronary CT angiography (CCTA) in clinical settings, we aimed to investigate whether reliable ECV estimation is possible using the contrast dose optimized for CCTA without additional contrast administration.
Twenty patients with known or suspected coronary artery disease who underwent CTDE with a dual-source scanner using two protocols (Protocols A and B) within 2 years were retrospectively enrolled. In Protocol A, CTDE was obtained with 0.84 ml/kg of iopamidol (370 mgI/ml) injected for CCTA. In Protocol B, stress CT perfusion imaging, which requires 40 ml of contrast medium, was added to Protocol A. ECV values calculated from the two protocols were compared.
Despite the different contrast doses, no significant difference in mean myocardial ECV was seen between Protocols A and B at the patient level (28.7 ± 4.3% vs. 28.7 ± 4.4%, respectively, P = 0.868). Excellent correlations in ECV were seen between the two protocols (r = 0.942, P < 0.001). Bland-Altman analysis showed slight bias (+0.06%), within a 95% limit of agreement of -2.9% and 3.0%. The coefficient of variation was 5.2%.
Reliable ECV estimation can be achieved with the contrast doses optimized for CCTA. Despite the differing contrast administration schemes and doses, ECV values calculated from the two protocols showed excellent agreement, indicating the robustness of ECV estimation by CT.
心脏细胞外容积分数（ECV）可以从 CT 延迟增强（CTDE）中得出，这可能有助于评估弥漫性心肌纤维化。然而，目前尚不清楚用于 ECV 估计的造影剂剂量。由于在临床环境中，CT 通常与冠状动脉 CT 血管造影（CCTA）联合进行 ECV 估计，因此我们旨在研究在不额外使用造影剂的情况下，使用优化 CCTA 的造影剂量是否可以可靠地进行 ECV 估计。
我们回顾性地纳入了 20 名在 2 年内接受过双源 CT 扫描仪 CTDE 的患者，这些患者患有或疑似患有冠心病，分别使用两种方案（方案 A 和方案 B）进行 CTDE。在方案 A 中，为 CCTA 注射 0.84ml/kg 的碘帕醇（370mgI/ml），并在方案 A 的基础上加入了 40ml 的对比剂，进行了负荷 CT 灌注成像。比较两种方案得出的 ECV 值。
尽管造影剂剂量不同，但在患者层面上，方案 A 和方案 B 之间的平均心肌 ECV 没有显著差异（分别为 28.7±4.3%和 28.7±4.4%，P=0.868）。两种方案之间的 ECV 具有极好的相关性（r=0.942，P<0.001）。Bland-Altman 分析显示，存在轻微的偏差（+0.06%），在 95%的一致性界限内为-2.9%和 3.0%。变异系数为 5.2%。
可以使用优化 CCTA 的造影剂量进行可靠的 ECV 估计。尽管造影剂给药方案和剂量不同，但两种方案计算得出的 ECV 值具有极好的一致性，这表明 CT 进行 ECV 估计具有稳健性。
