多层螺旋CT胰腺单期最佳扫描时相的研究

Multi-slice spiral CT single-phase enhanced scanning in the pancreas

目的 探讨多层螺旋CT（MSCT）单期增强扫描在对可疑胰腺癌诊断中合理的延迟时间.方法 随机选择50例健康志愿者,分为A、B两组.①A组行胰腺动态螺旋CT增强扫描,对比剂总量为120 ml,注射流率为2.5 ml/s,分别测定腹主动脉、门静脉、胰腺实质及肝脏实质在增强后不同时间点的CT值,得出时间-密度曲线.②B组行移床式、40s、60 s双期增强扫描,对比剂总量和流率同上,分别评价40 s与60 s胰周血管的显示率及显示程度.结果 ①时间-密度曲线结果提示,腹主动脉、门静脉强化到达峰值平均时间为60 s,胰腺实质强化到达峰值时间为50 s（50～70 s胰腺实质强化基本处于平台期）.肝脏实质强化到达峰值时间为60 s （60～80 s肝脏实质强化基本处于平台期）.并且有明显的密度差.②对于胰周血管的显示率,40 s和60 s均为100%.而对于显示程度,60 s扫描明显优于40 s扫描.结论 若对可疑胰腺癌行多层螺旋CT单期增强扫描.以对比剂总量为120 ml,注射流率为2.5 ml/s,延迟时间定为60 s较佳.

Objective To investigate the optimal single-phase scan enhanced delay time of MSCT in suspected pancreatic carcinoma. Methods Total 50 healthy individuals who were selected randomly were divided into group A and group B. Group A underwent enhanced serial dynamic CT scanning of the pancreas. By means of injection of 120 ml contrast at 2.5 ml/s rate, CT value of the peripancreatic aorta and portal vein, pancreatic and hepatic parenchyma was measured respectively in order to make the time-density curves of their enhancement. Incremental pancreatic multi-phase MSCT were performed in group B with the same dosage of contrast and injection rate. The displaying rate and degree （categorized on a scale of 0-3） of peripancreatic blood vessels at 40 s and 60 s evaluated emphatically. Results ①The results of enhanced serial dynamic CT scanning indicated that the time was 60 s for peak enhancement of the peripancreatic aorta, peripancreatic portal vein, 50 s for the pancreatic parenchyma （the platform stage for the pancreatic parenchyma ranged from 50 s to 70 s）, and 60 s for the hepatic parenchyma （the platform stage for the hepatic parenchyma ranged from 60 s to 80 s）. ②The results of step two showed that the displaying rate was 100% for the peripancreatic blood vessels at 40 s and 60 s. While for the displaying degree of peripancreatic blood vessels, 60 s was well superior to 40 s. Conclusion The optimal single-phase enhancement scan protocol of MSCT in examination of suspected pancreas carcinoma was the injection of contrast dosage of 120 ml at 2.5 ml/ s rate and the recommended delay time was 60 s.