What Changes Occur in the Brain of Veteran? A Magnetic Resonance Imaging and Proton Magnetic Resonance Spectroscopy Study

Abstract

The aims of this study were to assess the common anomalies in the MRI examinations of the heads of soldiers as well as to compare the relative concentration of magnetic resonance spectroscopy (MRS) metabolites in the brains of soldiers with those of healthy age-matched controls. Overall, 54 professional male soldiers were included in the study group and 46 healthy, age-matched males were in the control group. The relative values of N-acetylaspartate (NAA), choline (Cho), and myoinositol (mI) to creatine (Cr) were assessed. The mean relative concentrations of metabolites were compared between the study and the control group, separately for the frontal and occipital lobes, as well as between the right and left hemispheres within the study group only. The most frequent findings in the head MRI of the soldiers were: asymmetric lateral ventricles and dilated perivascular spaces, enlargement of the subarachnoid spaces, and the presence of cavum septum pellucidum and cavum vergae; the high frequency of sinus disease should also be noted. In the frontal lobes, the mI/Cr ratio was significantly higher (p = 0.005), while the NAA/Cr ratio was lower (p = 0.001), in the group of soldiers (vs. the study group). In the occipital lobes, the NAA/Cr ratio was significantly lower (p = 0.005) in the military personnel and there was a tendency to a higher mI/Cr ratio in the soldiers’ occipital lobes (p = 0.056) (vs. the study group). Comparing the metabolites between the left and right hemispheres in soldiers preferring a right shooting position, a significantly higher mI/Cr (p < 0.001) ratio was observed in the right frontal lobe (vs. the left) and a markedly lower NAA/Cr (p = 0.003) in the right occipital lobe (vs. the left). These changes are associated with astrogliosis and neuronal loss, presumably secondary to repetitive mild traumatic brain injury.