不同碘流率对肾动脉CTA图像最佳触发阈值的影响

Effect on threshold of triggered angiographic acquisition of renal artery CTA by different iodine flow rate

目的利用智能追踪(Smart Prep)技术探讨不同碘流率时肾动脉CTA的最佳触发阈值及其对肾CTA图像质量的影响。方法随机选择临床需行肾动脉CTA检查的患者420例,利用Smart Prep技术进行扫描。将所有患者随机平均分入A^D组,碘流率分别为0.90、1.11、1.20和1.48gI/s。每组随机平均分为7个亚组,分别按照不同阈值扫描,各亚组触发阈值分别为140~<150 HU、150~<160 HU、160~<170 HU、170~<180 HU、180~<190 HU、190~<200HU和200~210HU。采用5分制评分评价图像质量。分析各组的最佳阈值亚组,并进一步比较各最佳阈值亚组的图像质量的差异。结果 A^D组中,最佳触发扫描阈值范围分别为170~<190 HU、160~<190 HU、170~<180 HU和160~<180HU。触发阈值为170~<180HU时能够满足不同碘流率时肾动脉CTA的成像要求。各最佳阈值亚组间肾动脉CTA图像质量差异无统计学意义。结论不同碘流率配合最佳扫描触发阈值可获得优良的肾CTA图像。

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.