Evaluation of liver parenchymal blood flow with contrast-enhanced US: preliminary results in healthy and cirrhotic patients

RATIONALE AND OBJECTIVES: To determine whether changes in hepatic parenchymal blood flow in cirrhotic patients can be evaluated with contrast-enhanced ultrasound (US) after Levovist administration.

MATERIALS AND METHODS: Ten normal volunteers, 16 Child A and 16 Child C cirrhotic patients were evaluated with contrast-enhanced US. Frames obtained at progressively increasing pulse intervals of 2, 4, 7, and 10 seconds in the same scan plane during infusion of Levovist (300 mg/mL, 150 mL/h) have been digitally recorded. Pulse intervals versus signal intensity (PI-SI) plots were fitted to a straight line whose slope is proportional to the speed of blood in the liver parenchyma. Enhancement differences in late phase have been evaluated measuring the SI after 7 minutes from the beginning of the infusion.

RESULTS: The slope of the PI-SI plot of the Child A cirrhotic patients was significantly lower than the slope of the normal controls (P < 0.05); conversely, no significant differences were found between the slope of the patients with Child C cirrhosis and that of the normal controls. In comparison with the normal subjects, the average SI at late phase decreased significantly both in patients with Child A (P < 0.05) and Child C (P < 0.001) cirrhosis.

CONCLUSION: Microbubble contrast agents could provide a noninvasive tool to detect and monitor hemodynamic changes that occur in the cirrhotic liver. Changes in the hepatospecific properties at late phase have also been demonstrated.