Increase of Liver Function and Volume after ALPPS Determined by MRI in a Rat Model

Abstract

Introduction: It has been hypothesized that rapid increase of liver volume after ALPPS (Associating Liver Partition and Portal vein ligation for Staged hepatectomy) is not accompanied by a proportional increase of function. This study uses a rat models of major liver resection (LR), ALPPS and portal vein ligation (PVL) to test this hypothesis by measuring liver volume and function with contrast-enhanced magnetic resonance imaging (MRI). Methods: Wistar rats (200-250g) were randomly allocated to LR, ALPPS or PVL. T1-weighted MRI scans (7.0T MR Solutions,Guildford,UK) were performed until postoperative day 5. Uptake kinetics (2D-FLASH;TR/TE=589/8) of Primovist® (1mmol/kg,Bayer AG,Berlin, Germany) were measured in the future liver remnant (FLR) and spleen (blood pool). Liver volume was assessed during the excretion phase (2D-FLASH;TR/TE=4150/11; thickness 1mm). Liver function of the FLR was defined as the inverse value of time [min] from injection of Primovist® to maximum signal intensity multiplied by respective volume of the FLR [ccm]. Results: Percent increase of FLR volume overestimates FLR function at day 1 in all three, ALPPS, LR and PVL. From day 2, function and volume of the FLR increase proportionally in all procedures (Figure 1). Percent increase of liver function exceeds liver volume from day 2 until day 5 in ALPPS and LR, but not in PVL. Conclusion: This animal study rejects the hypothesis that functional increase is not proportional to volume increase in ALPPS. While function is impaired on day 1, ALPPS leads to a congruent increase of volume and function after day 1, similar to LR.