Lesser Andrew M, Newell Marc C, Samara Michael A, Gornick Charles, Grant Katharine, Garberich Ross, Han B Kelly
Minneapolis Heart Institute and Foundation, USA.
Siemens Medical Solutions, USA.
J Cardiovasc Comput Tomogr. 2016 Mar-Apr;10(2):173-8. doi: 10.1016/j.jcct.2015.12.009. Epub 2015 Dec 29.
The use of cardiac computed tomography (CT) for quantification of ventricular function is limited by relatively high radiation dose.
The goal of this study was to describe the radiation exposure and image quality of 70 kVp functional cardiac CT in patients with congenital heart disease (CHD).
A retrospective review of 70 kVp ECG gated functional CT scans using tube current modulation was performed in CHD patients at a single institution. Quantitative and qualitative (assessed by myocardial segment, 1-4; 1 = optimal) image quality was determined. Per segment image quality was compared between thin (1.5 mm) and thick (8 mm) reconstructions and by patient age and size. Scan DLP was used to estimate radiation dose.
72 scans were performed during the time of review (7/2013-6/2015). Median patient age was 19.5 years (8.0, 27.1) and BMI was 20.1 (16.6, 24.5) kg/m(2). Median functional scan DLP was 78.8 (45.5, 98) and unadjusted and adjusted procedural mSv were 1.10 (0.64, 1.37) and 1.13 (0.90, 1.37). Image quality of 1 was achieved in all myocardial segments in >75% of scans. Patients with a weight ≥75 kg were more likely to have a scan achieve optimal image when using thick reconstructions compared to thin (81.3% vs. 43.8%; p = 0.028).
Imaging of ventricular function with 70 kVp in CHD patients can be done with low radiation doses and provides diagnostic image quality, particularly for patients <75 kg. In larger patients, thicker slice reconstruction improved image quality.
心脏计算机断层扫描（CT）用于心室功能定量分析时，受到相对较高辐射剂量的限制。
本研究旨在描述先天性心脏病（CHD）患者行70 kVp功能性心脏CT时的辐射暴露情况及图像质量。
对单一机构的CHD患者进行回顾性分析，这些患者接受了采用管电流调制的70 kVp心电图门控功能性CT扫描。确定定量和定性（通过心肌节段评估，1 - 4级；1级 = 最佳）图像质量。比较薄重建（1.5 mm）和厚重建（8 mm）之间以及不同患者年龄和体型下各节段的图像质量。扫描剂量长度乘积（DLP）用于估计辐射剂量。
在回顾期间（2013年7月 - 2015年6月）共进行了72次扫描。患者年龄中位数为19.5岁（8.0，27.1），体重指数（BMI）为20.1（16.6，24.5）kg/m²。功能性扫描DLP中位数为78.8（45.5，98），未调整和调整后的程序毫西弗分别为1.10（0.64，1.37）和1.13（0.90，1.37）。超过75%的扫描中所有心肌节段的图像质量达到1级。与薄重建相比，体重≥75 kg的患者在采用厚重建时更有可能获得最佳图像（81.3%对43.8%；p = 0.028）。
CHD患者采用70 kVp进行心室功能成像时，可在低辐射剂量下完成，并提供诊断性图像质量，尤其是对于体重<75 kg的患者。对于体型较大的患者，更厚的层厚重建可改善图像质量。
