肺动脉CT三维血管成像低剂量扫描的应用

目的 探索肺动脉三维血管成像多层螺旋CT低剂量扫描的可行性,以及肺动脉容积三维处理(VR)图像的质量与平扫SD值的关系.方法 选取行肺动脉CT检查的受检者87人.选取志愿者63人为低剂量组,其余24人采用常规剂量扫描作为常规组.两者平扫均采用常规剂量150 mAs,低剂量肺动脉增强扫描采用60 mAs.图像进行VR后处理后,按A、B、C 3个等级进行评定,两组VR图像进行质量等级比较.低剂量组平扫图像测量CT值的标准差SD值,与增强的VR图像质量等级关系进行受试者操作特性曲线(ROC)分析.结果 常规剂量组VR图像等级为A级的达到100%,在低剂量组VR图像等级为A级的达到85.7%.平扫SD值与肺动脉VR图像的质量相关性分析,ROC曲线下面积为0.906.结论 肺动脉三维血管成像的低剂量扫描切实可行.

Application of low-dose in 3D 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.