This study was conducted to investigate the metabolic changes in the motor and motor association cortices following axonal injury in the internal capsule that was caused by deep intracerebral hematoma. Using proton magnetic resonance spectroscopy (1H MRS), the authors studied the primary motor cortices (M-1) and sup-plementary motor areas (SMA) of 9 hemiparetic patients with documentable hemi-paresis of varying severity, and we studied 10 normal volunteers as controls. To measure the M-1 and SMA biochemical changes, 4 separate single volumes of inter-est(VOIs) were located bilaterally in the affected and unaffected hemisphere (AH and UH).1H MRS provided a neuronal and axonal viability index by measuring levels of N-acetylaspartate (NAA) and creatine/phosphocreatine (Cr). The M-1/SMA NAA/Cr ratios of the AH and UH in patients, and the AH and normal volunteers were com-pared. The NAA/Cr ratios of the M-1 and SMA in AH, and the SMA in UH were sig-nificantly lower than those of normal volunteers. These 1H MRS findings indicate that axonal injury in the descending motor pathway at the level of internal capsule could induce metabolic changes in the higher centers of the motor pathway.
Adult ; Aged ; Aged, 80 and over ; Aspartic Acid/*analogs & derivatives/metabolism ; Basal Ganglia Hemorrhage/metabolism/*pathology ; Creatine/metabolism ; Female ; Humans ; *Magnetic Resonance Spectroscopy ; Male ; Middle Aged ; Motor Cortex/metabolism/*pathology ; Paresis/metabolism/*pathology ; Phosphocreatine/metabolism ; Protons ; Pyramidal Tracts/metabolism/*pathology

OBJECTIVE: To explore the applicability of magnetic resonance diffusion tensor imaging (DTI) for diagnosis of pyramidal tract damage in rats. METHODS: Marmarou's model was set up, followed by DTI scanning at 3, 12, 24 and 72 h post trauma to acquire the dispersion parameter of bilateral pyramidal tracts. Moreover, axonal varicosities per square millimeter and the percentage of positive area of axons demonstrated by beta-amyloid precursor protein (beta-APP) immunostaining were obtained, as well as the mean density and sum density of neurofilament (NF) 68 immunostaining. RESULTS: Axial diffusivity (AD), fraction anisotropy (FA) and relative anisotropy (RA) in the pyramidal tract were significantly and continuously reduced and reached to the bottom at 72h post trauma (P < 0.05) in accord with the gradient of axonal damage verified by beta-APP and NF68 immunostaining. Furthermore, the changes of AD, FA and RA showed a significant negative correlation with the beta-APP immunohistochemical results. CONCLUSION DTI has important value for early diagnosis in pyramidal tract damage.
Amyloid beta-Protein Precursor/metabolism* ; Animals ; Anisotropy ; Axons/pathology* ; Brain/pathology* ; Brain Injuries/pathology* ; Diffusion Magnetic Resonance Imaging/methods* ; Disease Models, Animal ; Image Processing, Computer-Assisted ; Male ; Neurofilament Proteins/metabolism* ; Pyramidal Tracts/pathology* ; Rats ; Rats, Sprague-Dawley ; Severity of Illness Index ; Time Factors