Eight patients with known focal nodular hyperplasia (FNH) were studied by electron beam tomography (EBT) in a multisection flow mode at defined time intervals after intravenous contrast agent injection. Various regions of interest (ROIs) were defined in the areas of FNH, normal liver parenchyma, aorta and portal vein. In each ROI density changes were measured and plotted against time. In those time-density curves (TDCs) the slope, the time of maximal enhancement and the absolute density value of peak enhancement were determined. Arterial tissue perfusion was calculated for normal liver parenchyma and FNH. In all eight patients significant differences in peak density (123.88 +/- 18.92 HU vs 102.5 +/- 15.49 HU, p = 0.012), in the rate of arterial contrast enhancement (252.63 +/- 28.05 HU min-1 vs 38.88 +/- 4.19 HU min-1, p = 0.012) and in the arterial tissue perfusion (1.36 +/- 0.19 ml min-1 cm-3 vs 0.21 +/- 0.03 ml min-1 cm-3, p = 0.012) between FNH and normal liver parenchyma were found. Perfusion values of normal liver parenchyma correspond to those determined by inert gas clearance. Further studies will determine the practicability of this quantitative method in the evaluation of global and other focal liver diseases.