Application of low-dose in 3a CT pulmonary angiography

Objective: To explore the feasibility of low-dose multi-slice computed tomography (MSCT) scan on pulmonary artery three-dimensional angiography, and the relationship between pulmonary VR image quality and the SD value of plain scan. Methods: Pulmonary artery CT examination was performed in 87 patients. 63 volunteers were administered with low dose as a low-dose group, and the other 24 were scanned with conventional dose as a routine group. Both plain scans were use conventional dose of pulmonary scan with 150 mAs, and the low-dose pulmonary enhanced scans were used with 60 mAs. The images were post-processed with volume rendering (VR) and classified into three grades A, B and C, and VR image quality levels of both groups compared. The receiver operating characteristic curve (ROC) was used to analyze the relationship between VR image quality level and SD value of plain scan image SD value. Results: The VR image level of A-class was 100% in the conventional dose group, and 85.7% was in the low dose group. According to the correlation analysis between the standard deviation (SD) value of plain scan image and pulmonary artery VR image quality, the area under curve in receiver-operated characteristic analysis was 0.906. Conclusions: The low-dose scan of pulmonary artery three-dimensional angiography is feasible. Using 60 mAs low-dose in pulmonary artery enhanced scan could ensure better image quality. With the SD value of the plain scan decreased, the pulmonary artery VR image quality is improved. (authors)