Tracking of neural stem cells in rats with intracerebral hemorrhage by the use of 3T MRI

Objective: To access the feasibility of clinically available 3T MRI to detect the migration of labeled neural stem cells (NSCs) in intracerebral hemorrhage (ICH) in a rat model. Materials and Methods: The ethics committee of our institution approved this study. ICH was induced by the injection of collagenase type IV into the right striatum of ten Sprague-Dawley rats. Human NSCs conjugated with Feridex (superparamagnetic iron oxide: SPIO) were transplanted into the left striatum one week after ICH induction. MRI was performed on a 3T scanner during the first, second,; third, fourth, and sixth weeks post-transplantation. MRI was obtained using coronal T2- and T2*-weighted sequences. Two rats were sacrificed every week after in vivo MRI in order to analyze the histological findings. Results: ICH in the right striatum was detected by MRI one and two weeks after transplantation without migration of the NSCs. There was no migration of the NSCs as seen on the histological findings one week after transplantation. The histological findings two weeks after transplantation showed a small number of NSCs along the corpus callosum. On MRI three weeks after transplantation, there was a hypointense line along the corpus callosum and decreased signal intensity in the right periventricular region. Histological findings three weeks after transplantation confirmed the presence of the hypointense line representing SPIO-labeled NSCs. MRI four and six weeks after transplantation showed a hypointense spot in the right periventricular region. The histological findings four and six weeks after transplantation showed the presence of prominent NSCs in the right periventricular region. Conclusion: 3T MRI can detect the migration of NSCs in rats with ICH along the corpus callosum. Therefore,3T MRI could be feasible for detecting the migration of NSCs in the clinical setting of stem cell therapy.