超重患者肺动脉CT血管成像70 kV/sn150 kV联合高级模拟迭代重建的图像质量评估

目的 定量评价超重（25 kg/m²≤BMI<30 kg/m²）患者低剂量双能量（70 kV/sn150 kV）肺动脉成像中70 kVp、非线性融合联合高级模拟迭代重建（ADMIRE）图像的质量。方法 2018年10月至2019年3月行双源CT双能量肺动脉成像的可疑肺栓塞患者共70例，70 kV/sn150 kV扫描模式的体质量指数正常者及超重者各35例，对比剂用量均为30 ml。患者扫描后均获得70 kVp、150 kVp、线性融合及非线性融合图像，评估体质量指数正常者70 kVp （组1）、体质指数正常者非线性融合（组2）、超重者70 kVp （组3）、超重者非线性融合（组4）图像质量指标，包括肺动脉CT值、图像噪声（SD）、信噪比（SNR）、对比噪声比（CNR），辐射剂量参数包括CT容积剂量指数（CTDI_vol）、剂量长度乘积（DLP）、有效剂量（E）。结果 4组肺动脉CT值差异无统计学意义（P>0.05）。段动脉SD值组1高于组4（t=2.69，P<0.05）。肺动脉主干、亚段动脉SNR值组2高于组3（t=1.44、5.40，P<0.05）。左肺动脉干SNR值组2高于组3、组4（t=1.52、1.52，P<0.05）。肺动脉主干、亚段动脉CNR值组2高于组3（t=1.45、5.01，P<0.05）。左肺动脉干CNR值组2高于组3、组4（t=1.50、1.50，P<0.05）。正常体质量指数组、超重组有效剂量为（1.60±0.54）、（1.88±0.45） mSv。结论 对于超重患者，肺动脉CT血管成像70 kV/sn150 kV双能量模式联合ADMIRE迭代重建的图像质量满足临床诊断，且对比剂用量及辐射剂量较低，是一种可行的双能量肺动脉扫描模式。

Image quality assessment of computed tomography pulmonary angiography performed using a 70 kV/sn150 kV model combined with the advanced modeled iterative reconstruction method in overweight patients

Objective To evaluate the image quality of dual-source computed tomography pulmonary angiography (DE-CTPA) with low-dose contrast agent using the advanced modeled iterative reconstruction (ADMIRE) method with 70 kVp and non-linear blending in overweight patients. Methods Seventy patients (normal BMI, 35; overweight, 35) with suspected pulmonary embolization who underwent DE-CTPA between October 2018 and March 2019 were included in this study. The imaging protocol included assessments at 70 kV/sn150 kV with 30 ml of contrast agent, and images were obtained at 70 kVp and 150 kVp with and without linear blending. The CT value, SD value, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) of pulmonary arteries were compared and analyzed among groups 1 (70 kVp, normal BMI), 2 (non-linear blending, normal BMI), 3 (70 kVp, overweight), and group 4 (non-linear blending, overweight ). The radiation dose parameters included CT volume dose index (CTDI_vol), dose length product (DLP), and effective dose (E ). Results The CT values for the pulmonary artery did not show significant differences among the four groups (P>0.05 ). The SD value of the segmental artery in group 1 was higher than that in group 4 (t=2.69,P<0.05 ). The SNR values of the pulmonary artery trunk and sub-segmental artery in group 2 were higher than those in group 3 (t=1.44, 5.40, P<0.05), while the corresponding value of the left pulmonary artery trunk in group 2 was higher than those in groups 3 and 4 (t=1.52, 1.52, P<0.05 ). The CNR values of the pulmonary artery trunk and sub-segmental artery in group 2 were higher than those in group 3 (t=1.45, 5.01, P<0.05) and that of the left pulmonary artery trunk in group 2 was higher than those in groups 3 and 4 (t=1.50,1.50, P<0.05 ). The E values for normal BMI and overweight patients were(1.60±0.54)mSv and(1.88±0.45)mSv, respectively. Conclusions For overweight patients, the CTPA protocol using ADMIRE with a 70 kV/sn150 kV scanning mode could yield diagnostic image quality with significantly lower radiation and contrast material doses.