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 / 中华放射医学与防护杂志

ABSTRACT

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.