Color Doppler ultrasonography in the identification and characterization of secondary focal lesions of the liver

: This study was aimed at assessing the potentials of color Doppler US in the detection of hepatic metastases by measuring changes in hepatic perfusion. Color-Doppler US was performed on 40 patients with multiple metastatic lesions (mean theta: 3 cm). In each patient both smaller and bigger lesions were studied--80 lesions on the whole. Differences in flow distribution (peritumoral or intratumoral) and the highest systolic peak flow velocity were investigated on color Doppler US scans. Hepatic arterial and portal venous blood flow measured in 40 patients with hepatic metastases were compared with those in 40 healthy controls. The two groups were homogeneous relative to age, sex, height and weight. The ratio of hepatic arterial to total liver blood flow (Doppler perfusion index, DPI) and the ratio of hepatic arterial to portal venous blood flow (Doppler flow ratio, DFR) were calculated. Color flow US scans were obtained in 56 of 80 metastatic lesions. We observed peritumoral flow in 76% of the lesions, intratumoral flow in 6% and mixed peritumoral and intratumoral flow in 18% of cases. The DPI and DFR values were significantly higher in the patients with liver metastases than in the control group. The changes in DPI and DFR resulted from an increase in hepatic arterial flow; no changes in portal venous blood flow were observed. These results suggest that Doppler measurements of hemodynamic hepatic changes may be of great value for the earlier detection of hepatic metastases.