Colorectal cancer: Diagnostic potential of CT measurements of hepatic perfusion and implications for contrast enhancement protocols

PURPOSE: To assess changes in hepatic perfusion in patients with colorectal cancer with computed tomography (CT), diagnostic potential of CT perfusion measurements, and implications for design of contrast enhancement protocols. MATERIALS AND METHODS: In 27 patients with colorectal cancer, arterial and portal perfusion were calculated from temporal changes in attenuation after intravenous administration of contrast material. RESULTS: Arterial perfusion greater than 0.25 mL/min/mL was seen in nine (82%) of the 11 patients with overt metastases versus six (38%) of the 16 patients with no overt metastases (P < .05). Portal perfusion of 0.25 mL/min/mL or less was found in five (46%) of the patients with overt metastases versus three (19%) of the patients with no overt metastases. Follow-up imaging showed progressive metastatic disease in three patients, all of whom had decreased portal perfusion. CONCLUSION: Increased arterial perfusion appears to be an indicator of liver metastases, whereas reduced portal perfusion may indicate progressive disease. Contrast enhancement protocols that are based on experience with normal livers may not be optimal for patients with metastases.