The application with low concentration of contrast media in the pulmonary angiography

ZHOU Hong-wei; WA NG Su-juan; WA NG Ye

Abstract：Objective To investigate the effect of low concentration of contrast media on the image quality of CT pulmo‐nary angiography .Methods 150 patients whose body mass index was from 20 to 25 were divided into 5 groups and under‐went CTPA .The total contrast media were offered at 0 .4 ml/kg to 150 patients .The contrast media concentration of 370 mgI/ml ,352 mgI/ml ,333 mgI/ml ,315 mgI/ml ,296 mgI/ml was offered for the 5 groups patients .The volume render‐ing ,maximum intensity projection and multi‐plane reformation were created to show the pulmonary angiography respec‐tively .The CT unit and standard deviation were measured at the pulmonary angiography ,the erector muscle of spine and the fat of chest wall .We calculated the signal‐noise ratio and contrast‐noise ratio with the CT value of pulmonary angiogra‐phy ,the erector muscle of spine and the fat of chest wall .The overall imaging quality was evaluated on a five‐point scale by two radiologists .The comparisons between 5 groups were tested by one‐way ANOVA analysis .Inter‐observer agree‐ment in subjective image quality grading was assessed by Kappa statistic .Results The SNR with the different concentra‐tions of contrast media was 25 .65 ± 3 .52 ,24 .48 ± 3 .43 ,23 .37 ± 2 .31 ,22 .27 ± 2 .23 ,21 .32 ± 2 .32 and the CNR was 28.85 ± 4 .32 ,26.88 ± 3 .59 ,25 .23 ± 3 .42 ,24 .25 ± 3 .62 ,23 .58 ± 3 .66 .The values by two independent radiologists were 4.63 ± 0 .41 ,4 .55 ± 0 .58 ,4 .46 ± 0 .65 ,4 .38 ± 0 .79 ,4 .41 ± 0 .57 .Datas of SNR and CNR were not statistically signifi‐cant in contrast media concentration of 370 mgI/ml ,352 mgI/ml ,333 mgI/ml ,315 mgI/ml ,296 mgI/ml ( F=5 .431 ,P>0.05) .In the comparison to image quality ,Kappa value was 0 .78 with the images with contrast media concentration of 370 mgI/ml ,352 mgI/ml ,333 mgI/ml ,315 mgI/ml ,296mgI/ml .Conclusion Recommend concentration of the contrast media was 296 mgI/ml at pulmonary angiography and injection total amount is 0 .4 ml/kg .