Institute of Diagnostic, Interventional and Pediatric Radiology, University Hospital Berne, University of Berne, Berne, Switzerland.
Clin Radiol. 2013 Feb;68(2):e79-86. doi: 10.1016/j.crad.2012.10.007. Epub 2012 Dec 6.
To assess the effect of an automatic tube voltage selection technique on image quality and radiation dose in abdominal computed tomography (CT) angiography of various body sizes.
An abdominal aortic phantom was filled with iodinated contrast medium and placed into three different cylindrical water containers, which simulated a small, intermediate-sized, and large patient. The phantom was scanned with a standard 120 kVp abdominal CT angiography protocol and with an optimized tube voltage protocol that was modulated by an automatic tube voltage technique. The attenuation of the aorta, background, and image noise was measured, and the contrast-to-noise ratio (CNR) was calculated. Three independent readers assessed the overall image quality.
The automatic tube voltage technique selected 70 kVp as the optimal tube voltage for the small phantom, 80 kVp for the intermediate phantom, and 100 kVp for the large phantom. Compared to the standard 120 kVp protocol, the automatic tube voltage selection yielded significantly increased CNR values in the small phantom (15.8 versus 19.4, p < 0.001), intermediate phantom (8.4 versus 8.7, p < 0.05), and large phantom (4.3 versus 4.6, p < 0.01). The automatic tube voltage selection resulted in a 55%, 49%, and 39% reduction in the volume CT dose index (CTDI(vol)) in the small, intermediate, and large phantoms, respectively. The subjective overall image quality of the three phantom sizes at different tube voltages ranged between poor and good.
Compared to a standard 120 kVp abdominal CT angiography protocol, the automatic tube voltage selection substantially reduced the radiation dose without compromising image quality in various simulated patient sizes.
评估自动管电压选择技术在不同体型腹部 CT 血管造影（CTA）中的图像质量和辐射剂量的影响。
将碘造影剂注入腹主动脉体模，并将其放置于三个不同的圆柱形水箱中，以模拟小、中、大体型患者。使用标准的 120 kVp 腹部 CTA 协议和通过自动管电压技术调制的优化管电压协议对体模进行扫描。测量主动脉、背景和图像噪声的衰减，并计算对比噪声比（CNR）。三位独立的读者评估整体图像质量。
自动管电压技术为小体型体模选择了 70 kVp 作为最佳管电压，为中体型体模选择了 80 kVp，为大体型体模选择了 100 kVp。与标准的 120 kVp 协议相比，自动管电压选择在小体型体模（15.8 比 19.4，p < 0.001）、中型体模（8.4 比 8.7，p < 0.05）和大体型体模（4.3 比 4.6，p < 0.01）中均显著提高了 CNR 值。自动管电压选择使小、中、大体型体模的容积 CT 剂量指数（CTDI(vol)）分别降低了 55%、49%和 39%。在不同管电压下，三种体型体模的整体图像质量主观评分为差至良。
与标准的 120 kVp 腹部 CTA 协议相比，自动管电压选择可在不影响各种模拟患者体型图像质量的情况下显著降低辐射剂量。
