Benefits of Simultaneous PET/MRI to Observe Heterogenous Changes During Brain Injury
Recently a group of researchers from the University of California, Davis and Genentech demonstrated successful multi-modal evaluation of the time course of a hypoxic challenge in mouse models of cerebral hypoxia-ischemia. The extent of brain injury is variable in these models, and along with the speed of ischemic changes, make a strong argument for simultaneous PET/MRI acquisition in small-animal stroke research.
In most animals, [18F]FDG PET images fused with anatomical MRI images showed reduced uptake in the occluded side relative to the non-occluded side, although this was not true in all cases likely due to animal variability. Executing sequential imaging studies and relying on software co-registration techniques would require the assumption that animal physiology has not significantly changed between imaging sessions; a potential pitfall given the rapid progression of ischemic brain injury. Simultaneous PET/MRI instrumentation can arm researchers with a new, powerful tool for multi-modal investigation into physiological changes during stroke and the effectiveness of novel interventional strategies.