螺旋CT胰腺增强扫描最佳时间窗的确定

目的确定螺旋CT双期增强扫描胰腺期的最适扫描时间窗。方法对100例非胰腺病患者行胰腺螺旋CT增强扫描。70例行双期扫描，扫描时间分别为开始注射造影剂后25～45s和65～85s；30例行单期扫描，扫描时间为开始注射造影剂后45～65s。造影剂用量95～100ml，注射速度3ml／s，层厚3～5mm,pitch=1.0。统计并计算正常胰腺在注射造影剂后各个时间点(25～85s)的密度增强值，并绘出时间-密度曲线。结果时间-密度曲线显示，胰腺的密度增强值在开始注射造影剂后43s达到峰值，胰腺密度增强值超过50Hu的时间区间为28～52s。结论以3ml／s速度注射离子型或非离子型造影剂95～100ml时，对窗宽为20s的扫描时间窗而言，胰腺期的扫描延迟时间为开始注射造影剂后30s。

THE OPTIMAL SCANNING TIME FOR THE PANCREAS IN HELICAL CT

Objective:To determine the optimal scan time of pancreatic phase. Methods:Helical CT was performed on 100 adult patients(66 men, 34 women, age range, 26～78 years, mean age, 49.27 years). After the initial unenhanced localizer scan was performed with 10mm collimation,95～100ml contrast medium was injected at the rate of 3ml/s. 70 patients were scanned with a delay of 25～45s and 65～85s respectively after the initiation of contrast bolus and the other 30 patients with a delay of 45～65s after the initiation of contrast bolus. The slice thickness was 3～ 5mm and the pitch was 1.0. The mean enhancement attenuation value per second after injection was calculated, from which a time-attenuation curve was obtained. Results: The time-attenuation curve showed that the enhancement attenuation value of normal pancreas tended to increase rapidly after the contrast bolus and reached the peak(69.58Hu) about 43s later. The time interval in which the mean enhancement attenuation value exceeded 50Hu was 28～52s after the initiation of injection of contrast medium. Conclusion:With the scan time window width was 20s,the optimal scan time,as shown in the time-attenuation enhancement curve of normal pancreas,was 30s after the initiation of 95～100ml contrast medium injection at the rate of 3ml/s .