Quantitative analysis of neural stem cell migration and tracer clearance in the rat brain by MRI.

Purpose: This study describes a quantitative method to estimate the migratory capacity of neural stem cells (NSCs) using magnetic resonance imaging.

Procedures: NSCs were labeled with ferumoxides and injected stereotaxically into the corpus callosum of the normal rat brain. Control subjects received either free ferumoxides or nonviable labeled cells. Subjects were scanned after initial injection and at 1 week. Image sets were coregistered, compared morphologically, and analyzed parametrically to determine migration speed.

Results: Subjects receiving injections of viable cells had a significantly greater spread of the tracer after 1 week than either control group (p< 0.05). The speed of migration for viable NSCs was significantly higher than that of controls along the corpus callosum (p < 0.05). Migratory speeds estimated from histology and imaging were significantly correlated.

Conclusions: This study provides a quantitative assessment of posttransplantation neural stem cell migration that is clearly distinguishable from tracer clearance.