Assessment of hepatic perfusion in transplanted livers by pharmacokinetic analysis of dynamic magnetic resonance measurements

Objective: The purpose of this study was to validate the assessment of hepatic perfusion by pharmacokinetic analysis of dynamic contrast-enhanced magnetic resonance image series. Materials and Methods: Dynamic measurements were performed with a saturation recovery turbo fast low angle shot (ie, FLASH) sequence over the course of approximately 4 minutes in 17 patients with transplanted livers. By pharmacokinetic analysis using an open 2-compartment model, we estimated and correlated an amplitude of signal enhancement, A, and the perfusion rate, k(p), with invasive perfusion measurements from implanted thermo-diffusion probes (F-TDP). Results: Data analysis for segment IV of the transplanted livers yielded a mean blood flow of 81 +/- 19 mL/min/100g and a mean perfusion rate of 13 +/- 6 minutes(-1). There was a significant correlation between FTDP and k(p) (r(S) = 0.64, P = 0.01) but not with A. Conclusions: Although our open 2-compartment model oversimplifies the complexity of hepatic perfusion, it allows a numerically robust estimation of regional blood flow per unit of blood volume. Thus, dynamic magnetic resonance imaging represents a noninvasive method to assess hepatic perfusion rate which can be visualized in color coded images.