肝脏多层螺旋CT扫描:不同注射流率对肝脏对比剂循环时间影响的探讨

目的　评价不同注射流率对肝脏对比剂循环时间的影响 ,确定多层螺旋CT(MDCT)肝脏 3个循环期的最佳时间。方法　选取正常人 50例 ,性别和年龄匹配后分为 2组 ,以不同注射流率(3和 5ml/s)从周围静脉内注入对比剂后的 10s开始扫描 ,在肝门层面每隔 4 5s采集 4层图像 ,达12 0s ,测量肝脏、门静脉及主动脉增强前后不同时间的CT值 ,绘制时间 -密度曲线 ,两组间进行t检验。结果　肝动脉期、门脉流入期及肝静脉期的起始时间 ,3ml/s组时间分别为 17.2 (11 7～ 2 2 6)s、2 7.1(2 3 1～ 3 3 0 )s和 59 3 (54 9～ 64 0 )s ;5ml/s组分别为 14 3 (10 3～ 17 6)s、2 2 5(17 5～ 2 7 5)s和 48 2(40 1～ 55 3 )s。门脉和肝脏峰值的升高在两组之间差异无显著性意义 (P >0 0 5) ,但是主动脉峰值有显著性意义 (P <0 0 0 1) ;而门脉流入期持续时间在两组之间无显著性意义。结论　 5ml/s流率注射对比剂较 3ml/s有早而较强的主动脉强化 ,而肝脏及门静脉强化峰值及对门静脉流入期的持续时间无明显影响。使用多层螺旋CT行肝脏扫描 ,采用 5ml/s注射流率技术为提高肝肿瘤检出率提供了理论依据。

Effect of contrast medium injection rate on hepatic circulatory time by using hepatic multirow-detector helical CT scanner

Objective To assess the effect of different injection rates of contrast medium on hepatic circulatory time and temporal window,and to d etermine the optimal protocols with multirow-detector helical CT (MDCT) Methods Fifty patients matched with sex and years were divided into two groups All patients received intravenous administration of 1 5 ml/kg contrast medium at different injection rate (3 ml/s and 5 ml/s) Scans were performed at the level of live r hilus and started 10 s following the administration of contrast medium,then repeated every 4 5 s for 4 images,and ended at 120 s CT attenuation value of pre and post contrast enhancement in the liver,aorta,and portal vein was measured with regions of interest,and time-density curves were constructed and statistically analyzed Results The delay mean time of hepatic artery,portal venous inflow,and hepatic venous phase was 17 2(11 7-22 6)s,27.1(23 1-33 0)s,and 59 3 (54 9-64 0)s,respectively for 3 ml/s,and 14 3 (10 3-17 6)s,22 5(17 5-27 5)s,and 48 2 (40 1-55 3)s, respectively for 5 ml/s The maximum peak enhancement of portal vein and hepatic parenchyma had no significant difference between the two groups,but that of aorta had significant difference between the two groups The duration of the portal venous inflow phase showed no significant difference between the two groups Conclusion 5 ml/s of injection rate could obtain earlier and greater enhancement of aorta and the duration of the portal venous inflow phase was not shortened The above injection technology provided the theoretical basis for the detection of hypervascular hepatic tumors