Department of Radiology and Radiological Science, Medical University of South Carolina, Ashley River Tower, 25 Courtenay Dr, MSC 226, Charleston, SC 29401, USA.
AJR Am J Roentgenol. 2012 Dec;199(6):1402-9. doi: 10.2214/AJR.12.8652.
The objective of our study was to evaluate radiation dose and quantitative image quality parameters at high-pitch CT angiography (CTA) of the aorta compared with conventional CTA.
We studied the examinations of 110 patients (65 men and 45 women; mean age ± SD, 64 ± 15 years) who had undergone CTA of the entire aorta on a second-generation dual-source CT system; 50 examinations were performed in high-pitch mode. The mean arterial attenuation, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and figure of merit (FOM) were calculated for the high-pitch CTA and conventional CTA groups. Radiation exposures were compared.
All studies were considered of diagnostic quality. At high-pitch CTA, the mean tube voltage and tube current-exposure time product were 118 ± 7 kV (SD) and 197 ± 78 mAs compared with 120 ± 1 kV and 258 ± 78 mAs, respectively, at conventional CTA (p < 0.05). The mean volume CT dose index, dose-length product, and effective dose were 8.1 ± 2.4 mGy, 561.1 ± 178.6 mGy × cm, and 9.6 ± 3.0 mSv at high-pitch CTA and 18.3 ± 7.7 mGy, 1162.6 ± 480.1 mGy × cm, and 19.8 ± 8.2 mSv at conventional CTA (p < 0.001). Attenuation was similar for both protocols, whereas significantly less contrast medium was injected for high-pitch CTA than for standard-pitch CTA (87.3 ± 16 mL vs 97.9 ± 16 mL, respectively; p < 0.01). The SNR and CNR were significantly lower in the high-pitch CTA examinations (p < 0.01), whereas the FOM was nonsignificantly higher. Twenty patients underwent both high-pitch CTA and conventional CTA, with a 45% reduction in radiation dose (p < 0.001).
High-pitch CTA of the aorta yields 45-50% reduction of radiation exposure as well as contrast medium savings with maintained vessel attenuation.
本研究旨在评估与常规 CT 血管造影（CTA）相比，高心率 CT 血管造影（CTA）主动脉成像的辐射剂量和定量图像质量参数。
我们研究了在第二代双源 CT 系统上进行的 110 例患者（65 例男性，45 例女性；平均年龄±标准差，64±15 岁）的整个主动脉 CTA 检查，其中 50 例采用高心率模式进行。计算高心率 CTA 和常规 CTA 组的动脉平均衰减、信噪比（SNR）、对比噪声比（CNR）和性能系数（FOM）。比较辐射暴露。
所有研究均被认为具有诊断质量。在高心率 CTA 中，管电压和管电流-曝光时间乘积分别为 118±7kV（SD）和 197±78mAs，而常规 CTA 分别为 120±1kV 和 258±78mAs（p<0.05）。高心率 CTA 的容积 CT 剂量指数、剂量-长度乘积和有效剂量分别为 8.1±2.4mGy、561.1±178.6mGy×cm 和 9.6±3.0mSv，而常规 CTA 分别为 18.3±7.7mGy、1162.6±480.1mGy×cm 和 19.8±8.2mSv（p<0.001）。两种方案的衰减相似，而高心率 CTA 注射的造影剂明显少于标准心率 CTA（分别为 87.3±16mL 和 97.9±16mL，p<0.01）。高心率 CTA 检查的 SNR 和 CNR 明显较低（p<0.01），而 FOM 则无显著差异。20 例患者同时进行了高心率 CTA 和常规 CTA，辐射剂量降低了 45%-50%（p<0.001）。
高心率 CTA 主动脉成像可降低 45%-50%的辐射剂量和造影剂用量，同时保持血管衰减。
