The efficacy of therapies based on neural stem cells (NSC) has been demonstrated in preclinical models of several central
nervous system (CNS) diseases. Before any potential human application of such promising therapies can be envisaged, there
are some important issues that need to be solved. The most relevant one is the requirement for a noninvasive technique capable
of monitoring NSC delivery, homing to target sites and trafficking. Knowledge of the location and temporospatial migration
of either transplanted or genetically modified NSC is of the utmost importance in analyzing mechanisms of correction and cell
distribution. Further, such a technique may represent a crucial step toward clinical application of NSC-based approaches in
humans, for both designing successful protocols and monitoring their outcome. Among the diverse imaging approaches available
for noninvasive cell tracking, such as nuclear medicine techniques, fluorescence and bioluminescence, magnetic resonance imaging
(MRI) has unique advantages. Its high temporospatial resolution, high sensitivity and specificity render MRI one of the most
promising imaging modalities available, since it allows dynamic visualization of migration of transplanted cells in animal
models and patients during clinically useful time periods. Different cellular and molecular labeling approaches for MRI depiction
of NSC are described and discussed in this review, as well as the most relevant issues to be considered in optimizing molecular
imaging techniques for clinical application.
Keywords Neural stem cells - Magnetic resonance imaging - Cellular imaging - Molecular imaging
Dr. Letterio Politi was awarded the Lucien Appel Prize in 2006 by the European Society of Neuroradiology for his research
into MR imaging of neural stem cells.