双源CT颅脑双能量血管成像技术中触发阈值的优化

Optimization of trigger threshold in automatic bolus tracking technique with cerebral dual-energy CTA with dual-source CT

目的探讨双源CT颅脑双能量血管成像技术中触发阈值的优化。方法45例病例随机分为3组进行颅脑双能量血管成像扫描,触发阈值分别定于100Hu、70Hu和50Hu,触发点定于第4颈椎平面颈总动脉。对重建后影像分阈值组进行颈内动脉颅内段、大脑前动脉、大脑中动脉近端、大脑后动脉和大脑大静脉五个点的CT值测量及影像评价,对比3阈值组的影像质量及静脉干扰度。结果3组动脉显影CT平均值及影像质量评分差异无统计学意义(P>0.05),动脉显影质量评分平均达到优良级别;3阈值组静脉显影平均CT值及动静脉差值差异有明显统计学意义(P<0.001),3组静脉干扰度评分差异有统计学意义(P<0.01)。结论双源CT颅脑双能量血管成像时,50HU触发阈值以动脉显影好、静脉干扰少为最佳选择。

Objective To explore the optimization of trigger threshold in automatic bolus tracking technique with cerebral dual-energy CTA with dual-source CT. Methods 45 patients were randomly divided into three groups and exam- ined with dual-energy CTA with triggered threshold as 100Hu,70Hu and 50Hu, respectively. ROI areas were located in common carotid arteries of C4 level. Reconstructed images were measured with CT values in five areas including cerebral segments of internal carotid arteries, anterior cerebral arteries, middle cerebral arteries, posterior cerebral arteries and cerebral veins. The arteries developing quality was evaluated. The images quality and pollution degree of veins were evaluated in three groups. Results The arteries average values and arteries image quality scores by CT in the three groups were not statistical different（P〉0. 05）. The scores of quality with arteries were Ⅰ and Ⅱ degree average. The veins and differentials of arteries and veins in three groups were remarkablely statistical different（P〈0. 001）. The veinspollution degree with three groups was statistical different（P〈0.01）. Conclusion 50Hu is the best trigger threshold of automatic bolus tracking technique with cerebral dual-energy CTA with dual-source CT, because of the superiority with high quality of arteries imaging and lower veinspolution.