Quantitative study of MR T-1 and T-2 relaxation times and (HMRS)-H-1 in gray matter of normal adult brain

摘要

abstract_textpObjective To evaluate magnetic resonance (MR) Imaging and H-1 magnetic resonance spectroscopy ((HMRS)-H-1) in the study of normal biochemical process of the brain, as well as differentiation of normal senile brain from cerebral diseases related to senility./ppMethods One hundred and eighty healthy adult volunteers were selected for MR examination and 60 other healthy subjects for (HMRS)-H-1 examination. Ages of subjects ranged from 18 to 80 years. They were divided into six age groups. A 0.35 T superconductive MR system was used to perform MR examination. Point resolved spectroscopy sequence was required for (HMRS)-H-1. The metabolites in the spectra included: N-acetylaspartate (NAA), choline compounds (CHO), creatine compounds (CR), myo-inositol (MI) glutamate and glutamine (Glu-n)./ppResults In 180 cases of MR, the shortest T-2 relaxation time occurred in the deep gray matter within the same age group while the length of T-1 relaxation time was ordered from low to high compared to age groups. T-2 relaxation time decreased as age increased. The peaks, ordered from high to low, were as follows in 60 cases of 1HMRS: NAA, CR, CHO, MI, Glu-n. The ratios of NAA/CR and Glu-n/CR were higher in the senile age group, while that of MI/CR was lower. The ratio of CHO/CR was increased as age decreased. The ratio of NAA/CR and MI/CR gradually decreased in relation to movement from the anterior to the posterior part of the brain; the ratio of CHO/CR was highest in the occipital cortex. Correlation of T, relaxation time and partial metabolite ratios to age were present in gray matter./ppConclusions Quantitative studies of MR T-1 and T-2 relaxation times and (HMRS)-H-1 are essential to evaluation of normal myelinization processes, neuronal integrity and age-related biochemical changes in the brain./p/abstract_text