The role of CT imaging in detection of hepatocellular carcinoma is well established and many strategies for opti- mizing data acquisition to improve CT detection of HCC were tried. Helical CT is an ideal method that fulfills the requirements of rapid scanning during the short interval of maximum hepatic enhancement. The aim of this work was to establish the optimal protocol for contrast injection and image acquisition to achieve maximum liver to tumor con- trast in cases of HCC. Thirty-five patients with pathologi- cally proven HCC were examined by triphasic spiral CT of the liver; they were divided into two groups, utilizing a different injection protocol in each group. It was found that 97.9% of the lesions were detected during arterial phase in both groups, while 85% of the lesions were seen in delayed phase and only 68% were detected in portal ve- nous phase. It was also noted that maximal tumor en- hancement occurs at a longer delay time and a higher rate of contrast injection. We concluded that in dynamic heli- cal CT of the liver, high injection rate and short delay time provide higher and faster enhancement of the hepatocellu- lar carcinoma and hence increase lesion detectability.
