Distinct MRI pattern in lesional and perilesional area after traumatic brain injury in rat — 11 months follow-up

Riikka J. Immonen, Irina Kharatishvili, Juha-Pekka Niskanen, Heidi Gröhn, Asla Pitkänen, Olli H.J. Gröhn
2009 Experimental Neurology  
To understand the dynamics of progressive brain damage after lateral fluid-percussion induced traumatic brain injury (TBI) in rat, which is the most widely used animal model of closed head TBI in humans, MRI follow-up of 11 months was performed. The evolution of tissue damage was quantified using MRI contrast parameters T 2 , T 1ρ , diffusion (D av ), and tissue atrophy in the focal cortical lesion and adjacent areas: the perifocal and contralateral cortex, and the ipsilateral and contralateral
more » ... hippocampus. In the primary cortical lesion area, which undergoes remarkable irreversible pathologic changes, MRI alterations start at 3 h postinjury and continue to progress for up to 6 months. In more mildly affected perifocal and hippocampal regions, the robust alterations in T 2 , T 1ρ , and D av at 3 h to 3 d post-injury normalize within the next 9-23 d, and thereafter, progressively increase for several weeks. The severity of damage in the perifocal and hippocampal areas 23 d post-injury appeared independent of the focal lesion volume. Magnetic resonance spectroscopy (MRS) performed at 5 and 10 months post-injury detected metabolic alterations in the ipsilateral hippocampus, suggesting ongoing neurodegeneration and inflammation. Our data show that TBI induced by lateral fluid-percussion injury triggers long-lasting alterations with region-dependent temporal profiles. Importantly, the temporal pattern in MRI parameters during the first 23 d post-injury can indicate the regions that will develop secondary damage. This information is valuable for targeting and timing interventions in studies aiming at alleviating or reversing the molecular and/or cellular cascades causing the delayed injury.
doi:10.1016/j.expneurol.2008.09.009 pmid:18929562 fatcat:df7djmegkbbgbesi2e7vuiygra