In vivo imaging of integration and function of striatal grafts in rodent and nonhuman primate animal models.

The assessment of the therapeutic efficacy of cell transplantation in repairing dysfunctional or degenerating brain tissues is conditioned by our capacity to follow up the grafted cells longitudinally in a noninvasive fashion. In fact, to date, postmortem histological analysis remains the main method used to characterize cell survival, maturation, differentiation, and absence of adverse effects upon intracerebral grafting. However, the increasing availability of sophisticated imaging techniques such as positron emission tomography, magnetic resonance imaging, and spectroscopy offers the possibility to directly exploit anatomical and functional information coming from the grafted cells in vivo. This, in turn, opens the way to the amelioration of existing applications and the development of new methodologies capable of addressing challenges arising in the preclinical transplantation field in views of a clinical application. This review summarizes the principles of the different imaging techniques and their validation in the preclinical setting in animal models of striatal degeneration.