Liver regeneration and function in donor and recipient after right lobe adult to adult living donor liver transplantation

Background. Regeneration of the liver to a predetermined size after resecti on or transplantation is a well described phenomenon, but the time course o ver which these events occur has not been well defined. It is not clear how initial liver mass, reperfusion, immunosuppression, or steatosis influence this process. Methods. Liver regeneration was assessed prospectively by volumetric magnet ic resonance imaging (MRI) in living right lobe liver donors and the recipi ents of these grafts. Imaging was performed at regular intervals through 60 days after resection/transplantation, and liver mass was determined. Liver function tests and synthetic function were monitored throughout the study period in donors and recipients of these grafts as well as recipients of ca daveric grafts. Results. MRL consistently overestimated liver mass by a mean of 45 g (+/-65 ) (range 10-123). Donor liver mass increased by 101%, 110%, 115%, and 144% at 7, 14, 30, and 60 days after resection, respectively. Recipient liver ma ss increased by 87, 101, 119, and 99% at 7, 14, 30, and 60 days after trans plantation, respectively. Steatosis did not influence the degree of regener ation or graft function, nor was there a functional difference between graf ts of >1% graft to recipient body weight ratio or <1%. Conclusions. MRI accurately determines right lobe mass. Most liver regenera tion occurs in the Ist week after resection or transplantation, and the tim e course does not differ significantly in donors or recipients. The mass of the graft or remnant segment affects the duration of the regeneration proc ess, with a smaller initial liver mass prolonging the course. Steatosis of <30% had no bearing on liver function or regeneration and, therefore, shoul d not be an absolute criterion for exclusion of donors. A calculated graft to recipient body weight ratio of 0.8% is adequate for right lobe living do nor liver transplantation.