Department of Radiology, Guangdong Academy of Medical Sciences, Guangdong General Hospital, 106 Zhongshan Er Road, Guangzhou 510080, PR China.
Eur J Radiol. 2012 Nov;81(11):3146-53. doi: 10.1016/j.ejrad.2012.04.017. Epub 2012 Jun 5.
To reduce radiation dose for retrospective ECG-triggered helical 256-slice CTCA by determining an optimal body size index to prospectively adjust tube current.
102 consecutive patients with suspected CAD underwent retrospective ECG-triggered CTCA using 256-slice CT scanner. Six body size indexes including BMI, nipple level (NL) bust, thoracic anteroposterior diameter at NL, chest circumference (CC) at NL, left main and right coronary artery (RCA) origin level were measured and their correlation with noise was evaluated using linear regression. An equation was developed to use this index to adjust tube current. Additional 102 consecutive patients were scanned with the index-based mAs adjustment. A t-test for independent samples was used to compare radiation dose levels with and without the index-based mAs selection method.
Linear regression indicated that CC RCA had the best correlation with noise (R2=0.603). Effective radiation dose was reduced from 16.6±0.9 to 9.8±2.7 mSv (p<0.01), i.e. 40.9% lower dose with the CC RCA-adapted tube current method. The image quality scores indicated no significant difference with and without the size-based mAs selection method.
An accessible measure of body size, such as CC RCA, can be used to adapt tube current for individualized radiation dose control.
通过确定最佳的体型指数来前瞻性地调整管电流，从而降低回顾性 ECG 触发的 256 层螺旋 CTCA 的辐射剂量。
102 例连续疑似 CAD 患者使用 256 层 CT 扫描仪进行回顾性 ECG 触发 CTCA。测量了 6 个体型指数，包括 BMI、乳头水平（NL）胸围、NL 处的胸前后径、NL 处的胸周径（CC）、左主干和右冠状动脉（RCA）起源水平，并使用线性回归评估它们与噪声的相关性。开发了一个方程，使用该指数来调整管电流。另外 102 例连续患者使用基于指数的 mAs 调整进行了扫描。使用独立样本 t 检验比较有无基于指数的 mAs 选择方法的辐射剂量水平。
线性回归表明 CC RCA 与噪声的相关性最好（R2=0.603）。有效辐射剂量从 16.6±0.9 降至 9.8±2.7 mSv（p<0.01），即使用 CC RCA 自适应管电流方法降低了 40.9%的剂量。图像质量评分表明，有无基于大小的 mAs 选择方法无显著差异。
可以使用一种易于获得的体型指标，如 CC RCA，来适应管电流，以实现个体化的辐射剂量控制。
