The pattern of brain metabolism in chronic steno-occlusive cerebral artery disease

BACKGROUND: Dispersion of gray matter and white matter and abnormal hemodynamic changes are common in patients with chronic stenosis cerebral artery disease. It is not easy to capture these abnormal changes with conventional magnetic resonance imaging (MRI). Magnetic resonance spectroscopy (MRS) is useful for obtaining metabolic information in either preclinical or clinical applications. The aim of our study was to apply MRS to non-invasively investigate changes in brain metabolism in MRI-negative patients with chronic cerebral artery steno-occlusive disease. METHODS: We performed MRS examinations with 3.0T MRI on 34 patients with severe unilateral middle cerebral artery (MCA) stenosis or occlusion without parenchymal abnormalities. Additionally, N-acetylaspartic acid (NAA), creatine (Cr), choline (Cho), NAA/Cr, and Cho/Cr in the coronal, parenchymal, and thalamic regions of the affected brain and contralateral brain were determined. The mean concentrations of NAA, Cr, Cho, NAA/Cr, and Cho/Cr in the coronal, parenchymal, and thalamic regions of the ipsilateral and contralateral brains were compared using the 2-tailed paired t-test. RESULTS: At the ipsilateral corona radiata and lenticular nucleus, the mean NAA was significantly lower, whereas the Cho and Cho/Cr were significantly higher than the contralateral corona radiata and lentiform nucleus (P<0.05). In addition, the creatine and NAA/Cr values in the coronal region of the affected side were significantly lower than those in the opposite side (P<0.05), but there was no significant difference between the pectin nuclei on both sides. No metabolic changes were found at the ipsilateral thalamus. CONCLUSIONS: In this study, we demonstrated that MRS could reveal metabolic changes and that the NAA, NAA/Cr, Cho, and Cho/Cr concentration might be used as indexes for evaluating neuronal damage in the chronic steno-occlusive cerebral artery disease, treatment strategies, and treatment effectiveness.