Hepatic perfusion index in the diagnosis of overt metastatic colorectal cancer.

The hepatic perfusion index (HPI) was measured in 180 patients with colorectal cancer: 109 with primary colorectal cancer, 38 with suspected recurrent colorectal cancer and 33 following curative resection of colorectal cancer. In 21 patients with proven metastatic disease serial imaging studies were performed. HPI was determined using the peak of the left kidney time-activity curve to define the division of arterial and portal blood flow. HPI was elevated (greater than 0.37) in 54 of 115 patients (47%) with no evidence of hepatic metastases, 17 of 27 patients (63%) with hepatic metastases at initial presentation and 21 of 25 (84%) with metastatic disease detected during follow-up. Only 4 of 13 patients (31%) with local recurrence but no evidence of liver metastases had an elevated HPI. Serial imaging of patients with metastatic liver disease demonstrated a rising HPI with clinical disease progression in 18 of 21 patients (86%). This study confirms the association of an elevated HPI with hepatic metastases and suggests that a rising HPI in serial studies is associated with progression of disease but highlights the deficiency of one single HPI estimation in the identification of patients with overt hepatic metastases.