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

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.