16层螺旋CT肝脏多期扫描的方法与实用价值

The Methods and Value of 16-Slice Spiral CT for Multi-Phasic Scans of Liver

目的:探讨16层螺旋CT肝脏多期扫描的方法及应用价值。方法:150例疑有肝脏病变的患者行16层螺旋CT多期扫描。层厚7.5mm,螺距1.375,扫描时间0.8s/r,静脉团注对比剂80～120ml,分别延时23～28s、45～50s58～65s行肝动脉期(动脉早期)、门静脉流注期(动脉晚期)和肝静脉期(实质期)扫描,并对图像作回顾性分析,比较增强前后腹主动脉、门静脉、肝静脉的CT值变化和后处理图像显示肝动脉、门静脉、肝静脉的能力。结果:16层螺旋CT肝脏多期扫描,肝脏血管增强后与增强前的密度差在91.9HU以上,VR、MIP、MPR图像上100%显示肝动脉(150/150),门静脉显示率为96.7%(145/150),肝静脉显示率为95.3%(143/150)。5例门静脉显示不清的病例中,3例为肝癌合并肝门区淋巴结转移,1例肝癌合并门静脉癌栓形成,1例为严重肝硬化合并腹水、脾肿大;7例肝静脉显示不清中有5例与门静脉显示不清的5例为相同病例,其余2例为严重肝硬化合并腹水。结论:16层螺旋CT肝脏多期扫描对评估肝脏病变、肝脏血管的正常、变异以及病变对血管的影响有很大帮助,但是对于严重肝硬化门静脉高压、门静脉狭窄、门静脉血栓(包括癌栓)形成的病例,显示门静脉和肝静脉不理想。

Objective:To assess the methods and value of 16-slice spiral CT for multi-phasic scans of liver.Methods:150 cases suspected of hepatic lesions were scanned with 16 slices spiral CT,slice thickness was 7.5mm,pich 1.375,120kV,280～340mA,helical scan time was 0.8 s/r,using the contrast media 80～120ml,flow rate 3.5～4ml/s,delay time 23～28s,45～50s and 58～65 sec for hepatic arterial phase,portal venous phase and hepatic venous phase respectively.All the axial images were compared with the CT value of abdominal aorta,portal vein and hepatic vein before and after injecting contrast media.And the raw datas were reconstructed in order to evaluate the value of displaying hepatic artery,portal vein and hepatic vein.Results:The CT value varied above 91.9HU before and after injecting contrast media.In VR,MIP and MPR images displaying for hepatic artery,portal vein and hepatic vein was 100% (150/150),96.7% (145/150) and 95.3% (143/150) respectively.Conclusion:Multi-phasic scans of liver with 16-slice spiral CT are helpful for evaluating hepatic lesion and variations of liver blood vessels but less satisfactory for demonstrating portal vein and hepatic vein in patients with severe cirrhosis,stricture and thrombosis.