Aristides Andres Capizzano MD, Presenter: Nothing to Disclose

Ricardo Jorge MD, Abstract Co-Author: Nothing to Disclose

Laura Acion BS, Abstract Co-Author: Nothing to Disclose

Juana Nicoll Toscano MD, Abstract Co-Author: Nothing to Disclose

Wendy R.K. Smoker MD, Abstract Co-Author: Nothing to Disclose

Robert Robinson MD, Abstract Co-Author: Nothing to Disclose

To quantify brain metabolite and volume changes, lesion distribution and neuropsychiatric correlates of traumatic brain injury (TBI).

Fourteen mild to moderate TBI patients (mean age ± SD: 42.5 ±17.6, 12 male) were evaluated up to 116 months after trauma with 12 age and sex matched controls (mean age ± SD: 44.42 ± 19.7, 9 male). The following sequences were acquired on a 3T Siemens Trio TIM scanner: 1) Coronal T1 weighted 3D MPRAGE; 2) Coronal T2 weighted TSE; 3) Single voxel PRESS of the left hippocampus with TR/TE=3000/30, 128 acquisitions, voxel size = 4.5 cc; and 4) 2D CSI PRESS of the anterior cingulate gyrus with TR/TE=3000/30, 4 acquisitions, voxel size = 1cc. N-acetylaspartate (NAA), creatine (Cr), choline, myo-inositol and glutamate signals were quantified in reference to water with LCModel. T1 and T2 weighted images were segmented into gray matter (GM), white matter (WM) and CSF and automatically assigned to brain lobes per Talairach coordinates using BRAINS2. Lesions were traced by a radiologist. At the time of imaging patients received psychiatric and neuropsychological evaluations with structured scales.

Predominant lesion volume distribution per lobe was: Frontal: 50.5% left and 11.7% right; and temporal: 21.1% left and 9.9% right. Patients had reduced left frontal WM volume (t=2.36, df=19, p=0.029), which inversely correlated with left frontal lesion volume (Spearman= -0.46, p=0.03). Patients also had reduced NAA/Cr in the left hippocampus (1.20 vs 1.43, t=2.3, df=21, p=0.03) and reduced NAA in left and right frontal WM (F(1,24)=6.54, p=0.02). No other significant volume differences between groups or correlations between imaging variables and neuropsychological or psychiatric scores were detected.

The studied sample consisted of TBI patients with predominantly frontal and left-biased lesions. Reduced NAA/Cr in the left hippocampus independent from atrophy agrees with known hippocampal neuronal susceptibility to TBI. Reduction of NAA in normal appearing frontal WM suggests axonal impairment secondary to predominantly frontal lesion burden.

Proton MRS shows chemical alterations in susceptible brain regions in TBI.

Capizzano, A, Jorge, R, Acion, L, Nicoll Toscano, J, Smoker, W, Robinson, R, Traumatic Brain Injury: Characterization with Proton MR Spectroscopy and Quantitative MRI.  Radiological Society of North America 2007 Scientific Assembly and Annual Meeting, November 25 - November 30, 2007 ,Chicago IL. http://archive.rsna.org/2007/5001366.html