The portal component of hepatic perfusion measured by dynamic CT - An indicator of hepatic parenchymal damage

CT can measure absolute hepatic arterial and portal venous perfusion; pilot data suggests these are raised and lowered, respectively, in cirrhosis. This study examined the value of functional CT in assessing cirrhosis, using the prothrombin ratio (PTR) as a marker for hepatic parenchymal damage. Twenty subjects with viral-induced cirrhosis (11 men and 9 women; 55.41 +/- 7.86 years) and 14 controls (8 men and 6 women; 48.36 +/- 17.67 years) were studied. A single section through the liver was scanned after bolus intravenous injection of 40 mi ioversol 320 mgI/ml. Hepatic arterial and portal perfusion was measured using a previously described technique. Hepatic portal perfusion was decreased in patients (0.66 +/- 0.21 ml/min/ml) compared with controls (1.11 +/- 0.23 ml/min/ml; P < 0.0001). A strong correlation was seen between PTR and portal perfusion (r = 0.662, P = 0.0038) in cirrhotics. Hepatic arterial perfusion did not differ between patients (0.088 +/- 0.082 ml/min/ml) and controls (0.091 +/- 0.067), and did not correlate with PTR. In conclusion, portal perfusion is reduced in cirrhosis, and this reduction correlates with PTR. It could thus be used as a marker of hepatic parenchymal damage. This technique may be useful in the follow-up of chronic liver disease, potentially reducing the need for serial liver biopsy.