Litmanovich Diana, Boiselle Phillip M, Bankier Alexander A, Kataoka Milliam L, Pianykh Oleg, Raptopoulos Vassilios
Department of Radiology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA.
J Comput Assist Tomogr. 2009 Nov-Dec;33(6):961-6. doi: 10.1097/RCT.0b013e318198cd18.
The aim of this study was to quantify the effect of a reduced-dose pulmonary computed tomographic (CT) angiography protocol on radiation dose and image quality in pregnant patients as compared with a standard protocol.
Twenty-six pregnant women with suspected pulmonary embolism underwent reduced-dose CT angiography (200 mA and 100 kV, from the aortic arch to the diaphragm). The matched control group standard protocol was 400 mA, 120 kilovolt (peak), and the entire thorax. The CT dose index, dose-length product, effective dose, image quality, and signal-to-noise ratio were assessed and compared with the Wilcoxon rank sum test result.
The CT dose index, mean dose-length product, and calculated effective dose were lower in the pregnancy group than in the controls: mean (SD), 5.21 (1.54) mGy versus 20.86 (5.59) mGy; 105.65 (39.77) mGy cm versus 575.71 (154.86) mGy cm, and 1.79 (0.676) msv versus 9.787 (2.63) msv, respectively (P < 0.0001). Quality scores of segmental (P = 0.266) and subsegmental (P = 0.207) arteries and arterial attenuation (P = 0.443) were similar.
In pregnant patients with suspected pulmonary embolism, combined reduction of kilovoltage and milliampere-second settings and z-axis coverage results in a substantial reduction of radiation dose while maintaining diagnostic imaging quality.
本研究旨在量化与标准方案相比，低剂量胸部计算机断层扫描（CT）血管造影方案对孕妇辐射剂量和图像质量的影响。
26名疑似肺栓塞的孕妇接受了低剂量CT血管造影（从主动脉弓至膈肌，管电流200 mA，管电压100 kV）。匹配的对照组采用标准方案（管电流400 mA，管电压120千伏[峰值]，扫描整个胸部）。评估CT剂量指数、剂量长度乘积、有效剂量、图像质量和信噪比，并通过Wilcoxon秩和检验结果进行比较。
妊娠组的CT剂量指数、平均剂量长度乘积和计算出的有效剂量均低于对照组：平均值（标准差）分别为5.21（1.54）mGy对20.86（5.59）mGy；105.65（39.77）mGy·cm对575.71（154.86）mGy·cm，以及1.79（0.676）mSv对9.787（2.63）mSv（P < 0.0001）。节段性动脉（P = 0.266）、亚节段性动脉（P = 0.207）的质量评分以及动脉衰减（P = 0.443）相似。
对于疑似肺栓塞的孕妇，降低管电压和毫安秒设置以及z轴覆盖范围相结合，可在保持诊断成像质量的同时大幅降低辐射剂量。
