Non-invasive quantification of liver perfusion with dynamic computed tomography and a dual-input one-compartmental model

Various liver diseases lead to significant alterations of the hepatic micro circulation. Therefore, quantification of hepatic perfusion has the potenti al to improve the assessment and management of liver diseases. Most methods used to quantify liver perfusion are invasive or controversial. This paper describes and validates a non-invasive method for the quantification of li ver perfusion using computed tomography (CT). Dynamic single-section CT of the liver was performed after intravenous bolus administration of a low-mol ecular-mass iodinated contrast agent. Hepatic, aortic and portal-venous tim e-density curves were fitted with a dual-in put one-compartmental model to calculate liver perfusion. Validation studies consisted of simultaneous mea surements of hepatic perfusion with CT and with radiolabelled microspheres in rabbits at rest and after adenosine infusion. The feasibility and reprod ucibility of the CT method in humans was assessed by three observers in 10 patients without liver disease. In rabbits, significant correlations were o bserved between perfusion measurements obtained with CT and with microspher es (r = 0.92 for total liver perfusion, r = 0.81 for arterial perfusion and r = 0.85 for portal perfusion). In patients, total liver plasma perfusion measured with CT was 112+/-28 ml.min(-1).100 ml(-1), arterial plasma perfus ion was 18+/-12 ml.min(-1).100 ml(-1) and portal plasma perfusion was 93+/- 31 ml.min(-1).100 ml(-1). The measurements obtained by the three observers were not significantly different from each other (P > 0.1). Our results ind icate that dynamic CT combined with a dual-input one-compartmental model pr ovides a valid and reliable method for the noninvasive quantification of pe rfusion in the normal liver.