Longitudinal magnetic resonance imaging quantitation of rat liver regeneration after partial hepatectomy.

This report demonstrates the advantages of using a noninvasive soft tissue imaging technique—magnetic resonance imaging (MRI)—to monitor liver regeneration after 70% partial hepatectomy in the rat in a longitudinal manner. Six animals were scanned prior to and on 6 subsequent occasions up to 9 days after surgical removal of the median and left lateral lobes. Within the observed time frame liver volumes were restored to approximately 88% of presurgery values. Final liver volumes correlated well with postmortem liver weights (R = 0.93). Regeneration is well-quantified empirically by a 4 parameter logistic equation: The rate of regeneration was maximal at 1.5 days, which coincided with the maximum increase of Mitotic Index—a measure of cell proliferation, determined in a subsequent study. Pre- and postpartial hepatectomy measurements remove two potentially confounding unknowns—the presurgery liver volume, and the amount of liver actually excised. 3D reconstructions of the liver effectively illustrate the mor...