Hepatic perfusion after liver transplantation: noninvasive measurement with dynamic single-section CT

To compare hepatic perfusion values after orthotopic liver transplantation with those in healthy volunteers.

Dynamic single-section computed tomography (CT) of the liver was performed in 50 participants, including 30 study patients who had undergone orthotopic liver transplantation and had no clinical evidence of postoperative complications (mean age, 53.7 years) and 20 healthy volunteers (control subjects) (mean age, 59.0 years). CT scans were obtained at a single level to include the liver, spleen, aorta, and portal vein. Scans were obtained over 88 seconds (one baseline scan followed by 16 scans every 2 seconds and, then, eight scans every 7 seconds) beginning with the injection of 40 mL of contrast agent (flow rate, 10 mL/sec). On each CT scan, the attenuation of these organs was measured in regions of interest to provide time-attenuation curves. From these data, the arterial, portal venous, and total perfusion of the liver were calculated, and the hepatic perfusion index was assessed.

In control subjects and study patients, respectively, mean arterial hepatic perfusion was 0.16 and 0.25 mL/min/mL (P = .001 [two-tailed paired Student t test]), mean portal venous perfusion was 1.22 and 1.26 mL/min/mL, mean total liver perfusion was 1.38 and 1.50 mL/min/mL (difference not significant), and the mean hepatic perfusion index was 0.12 and 0.16 (P = .002).

Arterial hepatic perfusion was significantly increased after orthotopic liver transplantation, but differences in portal venous and total liver perfusion were not significant. Dynamic single-section CT might also help evaluate hepatic vascular complications, chronic transplant rejection, and hepatic perfusion in liver cirrhosis.