In vivo dynamic 99mTc-HIDA scintigraphy after hepatocyte transplantation: a new method for the monitoring of graft function.

In vivo dynamic 99mTc-HIDA scintigraphy was tested as a method for graft function monitoring after hepatocyte transplantation (HTX). Bilirubin uridyldiphosphate glucuronyl transferase-deficient rats received 10(7) viable isolated hepatocytes from congenic nondeficient donors by intrasplenic injection. The transplanted rats were divided into 2 groups. Three months after HTX, one group underwent 99mTc-HIDA scintigraphy, the other was subjected to bile analysis for the detection of bilirubin glucuronides (the presence of which would indicate biochemical activity of transplanted hepatocytes). Histological examination of the spleen of all animals was performed at the end of the experiment. The same experimental protocol was applied to 10 sham-treated enzyme-deficient rats serving as controls. The scintigraphic studies showed that spleens of transplanted rats did accumulate 99mTc-HIDA, this in contrast to sham-treated rats. Furthermore, time-activity curves of liver and spleen of HTX-treated rats showed similar kinetic patterns, suggesting a biologically normal function of the hepatocytes grafted in the spleen. Bilirubin glucuronides were excreted by transplanted rats, not by control rats. Histological examination of the spleen revealed hepatocyte survival in all HTX-treated rats. These findings demonstrated a correlation between increased splenic uptake of 99mTc-HIDA and biochemical activity and morphological survival of intrasplenic donor hepatocytes. In conclusion, in vivo dynamic 99mTc-HIDA scintigraphy appears to be an ideal method for noninvasive graft function monitoring after intrasplenic HTX.