肝转移瘤的64层螺旋CT多期增强扫描的初步研究

Initial study on multi-phase contrast-enhanced 64 slice computed tomography scan of hepatic metastases

目的:细化肝转移瘤(HMs)64层螺旋CT多期增强扫描方案,探索最优延迟时间点,从而提高HMs病灶的检出率。方法:分析经手术病理或临床随访证实的符合纳入标准的40例HMs的MSCT多期增强扫描表现。所有病例均行CT平扫及动态6期增强扫描,采用智能追踪技术将常规增强3期细化为动脉早期(22～24 s),动脉中期(29～31 s),动脉晚期(37～39 s),门静脉早期(60～65 s),门静脉晚期(80～85 s),平衡期(150 s)。分析HMs的影像学表现,重点观察各个病灶在不同时相的强化特点,比较细化后各动脉期或门静脉期对病灶的检出率;并将动脉早、中或晚期与门静脉早期及晚期相互组合,优化检出、诊断HMs的最佳扫描方案。结果:门静脉晚期HMs病灶与周围肝实质的密度差值及CNR达到最大;动脉晚期+门静脉晚期组合检出的病灶数目最多。结论:动脉晚期+门静脉晚期组合可以最大程度上提高HMs检出率。

Objective： To investigate the point at which the best equilibrium phase image of 64 multi-slice spiral computed tomography （MSCT） could be acquired and thus to improve the detection rate of hepatic metastases. Methods：All imaging data of 40 patients confirmed by surgery and pathology or clinical follow-up were analyzed. Unenhanced and six multi-phase contrast-enhanced CT were performed in all patients. The scanning which was detailed by the technique of Smart Prep started at 22-24 s （early arterial phase）, 29-31 s （mid-arterial phase）, 37-39 s （late arterial phase）, 60-65 s （early portal venous phase）, 80-85 s （late portal venous phase） and 150 s （liver equilibrium phase） after initial injection of contrast medium. The imaging feature of the HMs, especially the contrast-enhanced characteristic of the lesions were analyzed. Compared the rates of the every detailed phase and the reorganized phases were detected. Results：The difference of CT value between the HMs and the liver parenchyma reached the peak point at the late portal venous phase, as well as the CNR between the HMs and liver parenchyma. Conclusion： Combination of late arterial phase and late portal venous phase can elevate the detection rate of HMs utmost.