Measurement of hepatic perfusion with dynamic computed tomography - Assessment of normal values and comparison of two methods to compensate for motion artifacts

RATIONALE AND OBJECTIVES. TO assess normal values of hepatic perfusion by d ynamic, single-section computed tomography, to compare two methods of data processing (a smoothing with a fitting procedure), and to evaluate the infl uence of motion artifacts. METHODS. Twenty-five volunteers with no history or suspicion of liver disea se were examined (age range, 32.8-81.1 years). All examinations were subjec tively ranked into groups 1 through 3 according to the degree of motion art ifacts (negligible, moderate, severe). All data were processed with a smoot hing procedure and a pharmacokinetic fitting procedure (TopFit), The arteri al, portal venous, acid total hepatic perfusion; the hepatic perfusion inde x (HPI); and the arterial/portal venous ratio (A/P ratio) were calculated w ith both procedures. RESULTS. Mean hepatic perfusion, as assessed with the fitting procedure and the smoothing procedure, respectively, was as follows: arterial, 0.20 and 0.22 mL.min(-1).mL(-1); portal venous, 1.02 and 1.24 mL.min(-1).mL(-1); tot al perfusion, 1.22 and 1.47 mL.min(-1).mL(-1); HPI, 16.4% and 15.4%; and A/ P ratio, 0.20 and 0.19. The differences were significant for the portal ven ous and total hepatic perfusion. The portal venous and total hepatic perfus ion values showed significant differences between group 1 and groups 2 and 3 for both procedures. HPI and the A/P ratio showed no significant differen ces at all. CONCLUSIONS. Motion artifacts and the type of data processing influence the assessment of the arterial, portal venous, and total hepatic perfusion but do not influence measurement of the HPI and the A/P ratio.