ABSTRACT
Objective To evaluate the effect on threshold of triggered angiographic acquisition by different iodine flow rate on renal artery CTA using Smart Prep tracking technique.Methods A total of 420 patients were randomly divided into A-D group with iodine flow rate of 0.90 gI/s,1.11 gI/s,1.20 gI/s,1.48 gI/s on average respectively.And each group were divided 7 subgroups with threshold 140-＜150 HU,150-＜ 160 HU,160-＜ 170 HU,170 ＜180 HU,180 ＜190 HU,190-＜200 HU,200-210 HU respectively.The quality of the images were graded from 1 5 by 2 radiologists.The best image quality subgroups were achieved,and the scores were compared among the best image quality subgroups.Results Image quality of renal CTA in each group were best performed with a threshold of 170-＜ 190 HU,160-＜ 190 HU,170-＜ 180 HU,160-＜ 180 HU respectively.When the threshold were 170-＜180 HU,image quality were good with all iodine flow rate groups.There was no significant difference among the scores of the best image quality subgroups (all P＞0.05).Conclusion Different iodine flow rate with appropriate threshold can acquire better image quality of renal CTA.
ABSTRACT
Objective To explore the related imaging factors about the change of systemic circulation time for aortic dissection (AD)patients.Methods Image data of 36 patients with AD and 30 patients in control group were analyzed retrospectively,the cor-relation analysis was made between the results of imaging measurement by using CT angiography (CTA)and the threshold time of the contrast agent in the left ventricular.3 6 patients with AD were divided into 2 groups (type A 1 7 cases and type B 1 9 cases)by using Stanford type.First,the threshold time in the left ventricular of the 3 groups were analyzed comparatively;next,the correla-tions between each CTA measured parameter and the threshold time in the left ventricle were analyzed.Results Threshold time in left ventricular of group Stanford A and group Stanford B were compared with the control group respectively,the overall mean difference was statistically significant (P 0.05).There was a significant correlation between threshold time in left ventricular and the ratio of false/true lumen (r=0.676,P 0.05).Conclusion The threshold time of left ventricular for aortic dissection patients is significantly longer than the normal control group,and is significantly related with the ratio of false/true lumen.