Abdominal Helical CT: Evaluation of Optimal Doses of Intravenous Contrast Material—A Prospective Randomized Study

PURPOSE: To determine the optimal dose of intravenous contrast material for helical computed tomography (CT) of the abdomen on the basis of patient weight. MATERIALS AND METHODS: A prospective randomized study of helical CT of the abdomen was performed by using different doses of intravenous contrast material in 221 patients (mean body weight, 57.3 kg) who were assigned randomly to three groups receiving 1.5, 2.0, or 2.5 mL/kg or a fixed dose of 100 mL of iopamidol 300. The degree of enhancement was scored visually. The CT numbers (HU) of the aorta, portal vein, liver, and pancreas were obtained at three levels of the abdomen. RESULTS: In arterial enhancement, the 2.0 mL/kg, 2.5 mL/kg, and fixed-dose groups were significantly better than the 1.5 mL/kg group, but there was no significant difference among the 2.0 mL/kg, 2.5 mL/kg, or fixed-dose groups. The degree of enhancement of the liver, pancreas, and portal vein increased with larger doses. At visual analysis, hepatic parenchymal enhancement was graded as good or excellent in 64% of the 1.5 mL/kg, 85% of the 2.0 mL/kg, 94% of the 2.5 mL/kg, and 65% of the fixed-dose groups. CONCLUSION: When dose was tailored to patient weight, the use of 2.0-2.5 mL/kg of intravenous contrast material produced better results than did 1.5 mL/kg or a fixed dose. Arterial enhancement did not differ among the 2.0 mL/kg, 2.5 mL/kg, or fixed-dose groups.