Purpose: To verify the following phenomenon in vivo using quantitative magnetic resonance imaging (MRI). Neuronal compression may occur following brain injuries in the cortex and hippocampus. As well being characterized by previous histological studies in rats, the majority of these neurons undergo hyperacute recovery rather than apoptotic death.
Materials and methods: Twenty male Wistar rats were assigned into injured or sham-injured groups (n = 10). The injured group underwent an electric trauma model to provoke compacted neuron formation. A T1 map was acquired prior to the injury and 10 T1 maps were acquired consecutively over a period of 2.5 hours after the injury, using a 3.0T scanner. Voxelwise statistical analyses were performed between timepoints. To enable comparison with the histological appearance of the compacted neurons, silver staining was performed on a sham-injured rat and five injured rats, 10, 40, 90, 150, and 300 minutes after the injury.
Results: A significant (corrected P < 0.05) increase in average T1 from the preinjury (895.24 msec) to the first postinjury timepoint (T1 = 951.37 msec) was followed by a significant (corrected P < 0.05) decrease (return) up to the last postinjury timepoint (T1 = 913.16 msec) in the voxels of the cortex and hippocampus. No significant (corrected P < 0.05) change in T1 was found in the sham-injured group.
Conclusion: The spatial and temporal linkages between the MRI T1 changes and the histological findings suggest that neuronal compaction and recovery is associated with T1 alterations. MRI therefore offers the possibility of in vivo investigations of neuronal compaction and recovery. J. MAGN. RESON. IMAGING 2016;44:814-822.
Keywords: MRI; brain trauma; compacted neuron; electroshock; neural recovery; rat.
© 2016 International Society for Magnetic Resonance in Medicine.