In vivo imaging of cell transplants in experimental ischemia.

The therapeutic potential of stem cells for regeneration after cerebral lesion has become of great interest. This is particularly so for neurodegenerative diseases as well as for stroke. Contrary to more conventional, cerebroprotective treatment approaches, the focus of regeneration lies in a longer time window during the chronic phase of the lesion evolution. Thus, in order to assess the true potential of a treatment strategy and to investigate the underlying mechanisms, observation of the temporal profile of both the cell dynamics as well as the organ response to the treatment is of paramount importance. This need for intraindividual longitudinal studies can be optimally met by the application of noninvasive imaging modalities. This chapter presents in breadth the potential of noninvasive imaging modalities for cell tracking with application focus to experimental stroke. While the lion's share of discussed studies is based on MRI, we have also included the contributions of positron emission tomography and of the increasingly important optical imaging modality.