双源双能量 CT 肺动脉成像辐射剂量与图像质量的比较研究

摘要

_目的：比较第一代双源双能量 CT（DECT）与第二代双源双能量 CT 肺动脉成像（CTPA）的辐射剂量和图像质量。方法：120例疑似肺栓塞患者行 DE-CTPA 检查，其中40例患者行第二代双源 DECT 80/Sn140 kV 检查（第一组），40例患者行第二代双源 DECT 100/Sn140 kV 检查（第二组），40例患者行第一代双源 DECT 140/80 kV 检查（第三组）。测量每例患者肺动脉主干、肺动脉段、空气及背部脂肪的 CT 值及标准差，对肺动脉图像进行主观评分，计算图像信噪比（SNR）、对比噪声比（CNR）及每例患者的有效剂量（ED）。结果：第一组肺动脉平均 CT 值[（354．1±73．4）HU]明显高于第二组[（290．1±73．1）HU，P＜0．001]和第三组[（303．9±73．3）HU，P＜0．001]，但第二组与第三组差异无统计学意义（P＝0．399）；第三组平均 SNR（24．8±8．4）低于第一组（40．4±12．9，P＜0．001）和第二组（44．6±12．9，P＜0．001），但第一组与第二组差异无统计学意义（P＝0．115）。第一组平均 CNR（435．3±77．7）明显高于第二组（355．8±77．8，P＜0．001）和第三组（384．8±79．0，P＝0．005），但第二组与第三组差异无统计学意义（P＝0．100）。三组图像主观质量评分差异无统计学意义（P＞0．05）。第一组的 ED[（1．2±0．3）mSv]明显低于第二组[（2．4±0．7）mSv]和第三组[（3．0±0．7）mSv]，差异均有统计学意义（P＜0．05）。结论：第二代双源 DECT 80/Sn140 kV 扫描方案可在大幅度降低辐射剂量的同时获得满足诊断需求的图像。%To compare radiation dose and image quality of CT pulmonary angiography (CTPA)using first generation and second-generation dual-source dual-energy CT (DECT).Methods:A total of 120 patients (40 in each group) underwent CTPA on a dual-source CT scanner (group 1:second generation DECT,40 patients,80/Sn140 kV;group 2:sec-ond generation DECT,40 patients,100/Sn140kV;group 3,first generation DECT,40 patients,140/80kV).The mean CT at-tenuations and standard deviations (SD)of main pulmonary,pulmonary arteries,the air,and the fat of the back at the level of the pulmonary trunk were measured.CT value,signal to noise ratio (SNR),contrast to noise ratio (CNR),and effective dose (ED)of pulmonary artery images were compared.Results:The CT values in the pulmonary arteries were significantly higher in group 1 [(354.1 ±73.4)HU,P<0.001]than those in group 2 [(290.1 ±73.1 )HU,P<0.001 ]and group 3 [(303.9±73.3)HU,P<0.001 ];however,no difference was found in CT values between groups 2 and 3 (P=0.399). Mean SNR were lower in group 3 (24.8 ±8.4)than group 1 (40.4 ±12.9,P<0.001 )and group 2 (44.6 ±12.9,P<0.001),however,no difference was found for SNR between groups 1 and 2 (P=0.115).Mean CNR were significantly high-er in group 1 (435.3±77.7)than group 2 (355.8±77.8,P<0.001)and group 3 (384.8±79.0,P=0.005),however,no difference was found for CNR between groups 2 and 3 (P=0.1).Mean ED were the lowest (P<0.001)in group 1.Conclu-sion:Second generation dual-source DECT with 80/Sn140 kV protocols allows for significant dose reduction and diagnostic image quality.