Department of Radiology, Duke University Medical Center, Durham, NC 27710, USA.
AJR Am J Roentgenol. 2009 Dec;193(6):1568-75. doi: 10.2214/AJR.09.2670.
The purpose of our study was to evaluate the effect of varying volumes and rates of contrast material, use of a saline chaser, and cardiac output on aortic enhancement characteristics in MDCT angiography (MDCTA) using a physiologic phantom.
Volumes of 75, 100, and 125 mL of iopamidol, 370 mg I/mL, were administered at rates of 4, 6, and 8 mL/s. The effect of a saline chaser (50 mL of normal saline, 8 mL/s) was evaluated for each volume and rate combination. Normal, reduced (33% and 50%), and increased (25%) cardiac outputs were simulated. Peak aortic enhancement and duration of peak aortic enhancement were recorded. Analysis of variance models were run with these effects, and the estimated mean levels for the sets of factor combinations were determined.
Lowering the volume of contrast material resulted in reduced peak enhancement (example, -56.2 HU [p < 0.0001] with 75 vs 125 mL) and reduced duration of 75% peak enhancement (example, -9.0 seconds [p < 0.0001] with 75 vs 125 mL). Increasing the rate resulted in increased peak enhancement (example, 104.5 HU [p < 0.0001] with a rate of 8 vs 4 mL/s) and decreased duration of 75% peak enhancement (example, -13.0 seconds [p < 0.001]). Use of a saline chaser resulted in increased peak enhancement, and this increase was inversely proportional to contrast material volume. Peak enhancement increased when reduced cardiac output was simulated. Peak enhancement decreased when increased cardiac output was simulated.
Reducing contrast material volume from 125 to 75 mL, increasing the rate to 6 or 8 mL/s, and use of a saline chaser result in an aortic enhancement profile that better matches the approximately 5-second imaging window possible with 64-MDCTA of the abdomen and pelvis. Even smaller volumes of contrast material may be adequate in patients with reduced cardiac output.
本研究旨在使用生理模型评估不同对比剂体积和流速、使用盐水冲注剂以及心输出量对 MDCT 血管造影（MDCTA）中主动脉增强特征的影响。
分别给予 75、100 和 125 mL 浓度为 370 mg I/mL 的碘帕醇，流速分别为 4、6 和 8 mL/s。评估每种体积和流速组合的盐水冲注剂（50 mL 生理盐水，8 mL/s）的效果。模拟正常、降低（33%和 50%）和增加（25%）的心输出量。记录峰值主动脉增强和峰值主动脉增强持续时间。用这些因素模型进行方差分析，确定因子组合集的估计平均水平。
降低对比剂体积导致峰值增强降低（例如，75 比 125 mL 时降低 56.2 HU [p < 0.0001]），75%峰值增强持续时间缩短（例如，75 比 125 mL 时缩短 9.0 秒 [p < 0.0001]）。增加流速导致峰值增强增加（例如，8 比 4 mL/s 时增加 104.5 HU [p < 0.0001]），75%峰值增强持续时间缩短（例如，75 比 125 mL 时缩短 13.0 秒 [p < 0.001]）。使用盐水冲注剂可增加峰值增强，且这种增加与对比剂体积成反比。模拟降低心输出量时，峰值增强增加。模拟增加心输出量时，峰值增强减少。
从 125 降至 75 mL 可减少对比剂体积，增加至 6 或 8 mL/s，并使用盐水冲注剂可使主动脉增强曲线与腹部和骨盆 64-MDCTA 约 5 秒的成像窗口更好匹配。对于心输出量降低的患者，甚至更小的对比剂体积可能就足够了。
