J Neurotrauma. 2012 Aug 20. [Epub ahead of print]
Multi-modal magnetic resonance imaging in the acute and sub-acute phase of mild traumatic brain injury: Can we see the difference?
Toth A, Kovacs N, Perlaki G, Orsi G, Aradi M, Komaromy H, Ezer E, Bukovics P, Farkas O, Janszky J, Doczi T, Buki A M D Ph D, Schwarcz A.
University of Pécs, Department of Neurology, Rét u. 2., Pécs, Baranya, Hungary, 7623, +36 30 957 9699; firstname.lastname@example.org.
Advanced MRI methods were shown to be able to detect the subtle structural consequences of mild traumatic brain injury (mTBI). The objective of this study was to investigate the acute structural alterations and recovery after mTBI, using diffusion tensor imaging (DTI) to reveal axonal pathology, volumetric analysis and susceptibility weighted imaging (SWI) to detect micro hemorrhage. Fourteen mTBI patients with negative CT scans underwent MR imaging within 3 days; and one month after injury. High resolution T1-weighted imaging, DTI and SWI were performed at both time points. A control group of 14 matched volunteers were also examined following the same imaging protocol and time interval. Tract Based Spatial Statistics (TBSS) was carried out on DTI data to reveal group differences. T1-weighted images were fed into Freesurfer volumetric analysis. TBSS showed fractional anisotropy (FA) to be significantly (corrected p<0.05) lower, and mean diffusivity (MD) to be higher in the mTBI group in several white matter tracts (FA=40737; MD=39078 voxels) compared to controls at 72 hours after injury and still one month later for FA. Longitudinal analysis revealed significant change (i.e. normalization) of FA and MD over one month dominantly in the left hemisphere (FA=3408; MD=7450 voxels). A significant (p<0.05) decrease in cortical volumes (mean 1%) and increase in ventricular volumes (mean 3,4%) appeared at one month after injury in the mTBI group. SWI did not reveal micro hemorrhage in our patients. Our findings present dynamic micro- and macro-structural changes occurring in the acute to sub-acute phase in mTBI, in very mildly injured patients lacking micro hemorrhage detectable by SWI. These results underscore the importance of strictly defined image acquisition time points when performing MRI studies on patients with mTBI.
PMID: 22905918 [PubMed – as supplied by publisher]