Optimal contrast medium protocol in computed tomography during arterial portography for detection of hepatoma

Due to the high sensitivity of computed tomography during arterial portography (CTAP), it has become an important method used in the preoperative planning for the treatment of patients with primary or secondary malignant neoplasms of the liver According to different reports, various doses of contrast material and rates of injection have been used over the past several years. For setting a rational routine protocol, we carried out this study to evaluate the optimal concentration of contrast media used in CTAP for detection of hepatic tumors. The overall sensitivities of tumor detection were 91%, 92% and 93% among three groups using 300 mgI/ml, 225 mgI/ml, and 150 mgI/ml, respectively. There were no statistically significant differences in the tumor detection rate among the groups. However, lesions were better demarcated from the liver parenchyma in 300 mgI/ml and 225 mgI/ml groups than 150 mgI/ml group. There was also more homogeneity of portal perfusion in the 225 mgI/ml groups than the 300mgI/ml group. According to our study results, 80 ml of diluted contrast medium with the concentration of 225 mgI/ml injected at a rate of 2 ml/sec was satisfactory for the detection of hepatic tumors using CTAP. In conclusion, CTAP can be done confidently using slower injection rates and smaller amounts of contrast medium with intermediate concentrations for detection of hepatomas than the protocols reported in the literature.