Progressive metabolic and structural cerebral perturbations after traumatic brain injury: An in vivo imaging study in the rat

Ying R. Liu, Lisa Cardamone, R. Edward Hogan, Marie Claude Gregoire, John P. Williams, Rod J. Hicks, David Binns, Amelia Koe, Nigel C. Jones, Damian E. Myers, Terence J. O'Brien, Viviane Bouilleret

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56 Citations (Scopus)

Abstract

Traumatic brain injury (TBI) has a high incidence of long-term neurologic and neuropsychiatric morbidity. Metabolic and structural changes in rat brains were assessed after TBI using serial 18F-FDG PET and 3-dimensional MRI in vivo. Methods: Rats underwent lateral fluid percussion injury (FPI; n = 16) or a sham procedure (n = 11). PET and MR images were acquired at 1 wk and at 1, 3, and 6 mo after injury. Morphologic changes were assessed using MRI-based regions of interest, and hippocampal shape changes were assessed with large-deformation high-dimensional mapping. Metabolic changes were assessed using region-of-interest analysis and statistical parametric mapping with the flexible factorial analysis. Anxiety-like behavior and learning were assessed at 1, 3, and 6 mo after injury. Results: PET analyses showed widespread hypometabolism in injured rats, in particular involving the ipsilateral cortex, hippocampus, and amygdalae, present at 1 wk after FPI, most prominent at 1 mo, and then decreasing. Compared with the sham group, rats in the FPI group had decreased structural volume which progressively increased over 3-6 mo, occurring in the ipsilateral cortex, hippocampus, and ventricles after FPI (P < 0.05). Large-deformation high-dimensional mapping showed evolving hippocampal shape changes across the 6 mo after FPI. Injured rats displayed increased anxiety-like behavior (P < 0.05), but there were no direct correlations between the severity of the behavior abnormalities and functional or structural imaging changes. Conclusion: In selected brain structures, FPI induces early hypometabolism and delayed progressive atrophic changes that are dynamic and continue to evolve for months. These findings have implications for the understanding of the pathophysiology and evolution of long-term neurologic morbidity following TBI, and indicate an extended window for targeted neuroprotective interventions.

Original languageEnglish
Pages (from-to)1788-1795
Number of pages8
JournalJournal of Nuclear Medicine
Volume51
Issue number11
DOIs
Publication statusPublished - 1 Nov 2010

Keywords

  • F-FDG PET
  • Anxiety
  • MRI
  • Rat
  • Traumatic brain injury

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