多层螺旋CT肝静脉成像后处理技术

Study on postprocessing techniques of multi-detector row CT hepatic venography

目的:探讨多层螺旋CT肝静脉成像技术及后处理方法。方法:20例患者行肝脏动脉期、门静脉期及肝静脉期3期扫描,肝静脉期图像分别行1mm及2mm层厚重建,图像重叠60%,分别对两组薄层图像行最大密度投影(MIP)、多平面重组(MPR)、遮蔽表面显示(SSD)和容积再现(VR),比较各种后处理技术显示肝静脉的优缺点。结果:所有病例均清晰显示第二肝门的肝左、肝中及肝右静脉,20例中有18例显示第三肝门静脉属支,另2例在第二肝门以下未见明显肝静脉引流入下腔静脉。1mm重建层厚较2mm重建层厚对微小肝静脉的显示更好,图像质量好。4种后处理方法中轴面薄层MIP显示的引流静脉数目最多,冠状面MPR对第二肝门及第三肝门的解剖关系显示最好。VR及SSD对门静脉系、第二肝门及第三肝门各静脉属支立体结构关系显示最好。结论:多层螺旋CT肝静脉成像可显示主要肝静脉,1mm重建层厚,60%影像重叠后的重建图像质量较好,各种重组技术相结合可清晰、立体显示门静脉系、第二肝门及第三肝门的结构。

Objective：To discuss the technique and postprocessing of multi-detector row CT hepatic venography.Methods：20 patients underwent tri-phase MDCT using a Siemens Sensation 16 scanner.Contrast material （80~100ml） was injected at a rate of 3ml/s.The arterial phase,portal venous phase and hepatic venous phase images were conducted with a fixed scanning delay of 30s,65s and 85s after contrast material administration respectively.The hepatic venous phase images were reconstructed at an interval of 1.0mm and 2mm respectively.Maximum intensity projection,multi-plannar reformation,shaded surface display,and volume rendering were created to show the hepatic veins.Results：The hepatic veins of the second hilum （including left,middle and right hepatic veins） were shown clearly in all cases,and hepatic veins of the third hilum were shown in 18 cases.Comparing the advantages of four postprocessing methods in showing the third hilum,SSD could demonstrate stereoscopic structure of the portal veins,second hilum hepatic veins and third hilum hepatic veins.Conclusion：Multi-detector row CT hepatic venography can demonstrate the main hepatic veins clearly.Images after being reconstructed at an interval of 1.0mm were to be better postprocessed.All postprocessing methods can be used to demonstrate stereochemical structure of the portal veins and the hepatic veins.