Background. Regeneration of the liver to a predetermined size after resection or transplantation is a well described phenomenon, but the time course over 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 magnetic resonance imaging (MRI) in living right lobe liver donors and the recipients 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 cadaveric grafts.
Results. MRI 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 mass increased by 87,101, 119, and 99% at 7, 14, 30, and 60 days after transplantation, respectively. Steatosis did not influence the degree of regeneration or graft function, nor was there a functional difference between grafts of >1% graft to recipient body weight ratio or <1%.
Conclusions. MRI accurately determines right lobe mass. Most liver regeneration occurs in the 1st week after resection or transplantation, and the time course does not differ significantly in donors or recipients. The mass of the graft or remnant segment affects the duration of the regeneration process, with a smaller initial liver mass prolonging the course. Steatosis of <30% had no bearing on liver function or regeneration and, therefore, should 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 donor liver transplantation.
Departments of Surgery, Medicine, and Radiology, Medical College of Virginia, Virginia Commonwealth University, Richmond Virginia 23219
3 Division of Transplantation, Department of Surgery.
4 Section of Hepatology and Liver Transplantation, Division of Gastroenterology, Department of Medicine.
5 Department of Radiology.
Received 14 July 1999.
Accepted 23 August 1999.
6 Address correspondence to: Amadeo Marcos, M.D., Division of Transplantation, Medical College of Virginia, P.O. Box 980057, Richmond, Virginia 23298-0057.
1 Some of these data were presented at the 18th Annual Meeting of the American Society of Transplantation, May 15-19, 1999, Chicago, Illinois.
2 This work was partially supported by a grant from Fujisawa (Amadeo Marcos, MD).