THE USE OF DUPLEX SONOGRAPHY IN THE DETECTION OF COLORECTAL HEPATIC METASTASES

Conventional imaging techniques are of limited value in identifying small liver metastases. Indirect methods of measuring blood-flow have shown that metastases may be associated with subtle changes in liver blood-flow. Doppler ultrasonography has the ability to measure liver blood-flow directly. In this study, the role of duplex sonography in the detection of hepatic metastases was evaluated. Hepatic arterial and portal venous blood-flows were measured in 30 patients awaiting surgery for colorectal cancer and 16 controls. The ratio of hepatic arterial: portal venous blood-flow (Doppler flow ratio; DFR) and the ratio of hepatic arterial: hepatic arterial and portal venous blood-flow (Doppler perfusion index; DPI) were calculated. Clear separation of the DPI and DFR values of controls and patients with histologically confirmed liver metastases was observed (P < 0.001). The data suggest that the measurement of liver blood-flow by duplex sonography may be of value in the diagnosis of colorectal liver metastases.