BACKGROUND AND PURPOSE: Knowledge of age-related physiological changes in the human brain is a prerequisite to identify neurodegenerative diseases. Therefore, in this study whole-brain ¹H-MRS was used in combination with quantitative MR imaging to study the effects of normal aging on healthy human brain metabolites and microstructure. MATERIALS AND METHODS: Sixty healthy volunteers, 21–70 years of age, were studied. Brain maps of the metabolites NAA, creatine and phosphocreatine, and Cho and the tissue irreversible and reversible transverse relaxation times T2 and T2′ were derived from the datasets. The relative metabolite concentrations and the values of relaxation times were measured with ROIs placed within the frontal and parietal WM, centrum semiovale, splenium of the corpus callosum, hand motor area, occipital GM, putamen, thalamus, pons ventral/dorsal, and cerebellar white matter and posterior lobe. Linear regression analysis and Pearson correlation tests were used to analyze the data. RESULTS: Aging resulted in decreased NAA concentrations in the occipital GM, putamen, splenium of the corpus callosum, and pons ventral and decreased creatine and phosphocreatine concentrations in the pons dorsal and putamen. Cho concentrations did not change significantly in selected brain regions. T2 increased in the cerebellar white matter and decreased in the splenium of the corpus callosum with aging, while the T2′ decreased in the occipital GM, hand motor area, and putamen, and increased in the splenium of the corpus callosum. Correlations were found between NAA concentrations and T2′ in the occipital GM and putamen and between creatine and phosphocreatine concentrations and T2′ in the putamen. CONCLUSIONS: The effects of normal aging on brain metabolites and microstructure are region-dependent. Correlations between both processes are evident in the gray matter. The obtained data could be used as references for future studies on patients.

Objective: To estimate alterations in neurometabolic profile of patients with early stage Parkinson's disease (PD) by using a short echo-time whole brain magnetic resonance spectroscopic imaging (wbMRSI) as possible biomarker for early diagnosis and monitoring of PD. Methods: 20 PD patients in early stage (H&Y ≤ 2) without evidence of severe other diseases and 20 age and sex matched healthy controls underwent wbMRSI. In each subject brain regional concentrations of metabolites N-acetyl-aspartate (NAA), choline (Cho), total creatine (tCr), glutamine (Gln), glutamate (Glu), and myo-inositol (mIns) were obtained in atlas-defined lobar structures including subcortical basal ganglia structures (the left and right frontal lobes, temporal lobes, parietal lobes, occipital lobes, and the cerebellum) and compared between patients and matched healthy controls. Clinical characteristics of the PD patients were correlated with spectroscopic findings. Results: In comparison to controls the PD patients revealed altered lobar metabolite levels in all brain lobes contralateral to dominantly affected body side, i.e., decreases of temporal NAA, Cho, and tCr, parietal NAA and tCr, and frontal as well as occipital NAA. The frontal NAA correlated negatively with the MDS-UPDRS II (R = 22120.585, p = 0.008), MDS-UPDRS IV (R = −0.458, p = 0.048) and total MDS-UPDRS scores (R = −0.679, p = 0.001). Conclusion: In early PD stages metabolic alterations are evident in all contralateral brain lobes demonstrating that the neurodegenerative process affects not only local areas by dopaminergic denervation, but also the functional network within different brain regions. The wbMRSI-detectable brain metabolic alterations reveal the potential to serve as biomarkers for early PD.

BACKGROUND AND PURPOSE: Development of callosal fibers is important for psychomotor and cognitive functions. We hypothesized that brain maturation changes are detectable beyond 2 years of age by using diffusion tensor imaging (DTI) of the corpus callosum (CC). MATERIALS AND METHODS: T2 and fractional anisotropy (FA) maps of the brain of 55 healthy subjects between 0.2 and 39 years of age were obtained. Quantitative T2 and FA values were measured at the genu and splenium of the CC (gCC and sCC). Fiber tracking, volumetric determination, and the fiber density calculations of the CC were related to age. A paired t test was used for significant differences between the values at the gCC and sCC. RESULTS: T2 relaxation times at gCC and sCC decrease fast in the first months of life and very little after 2 years of age. The FAgCC increases until 5 years of age and remains nearly constant thereafter; it showed a significant increase from 0 to 2 years versus 2–5 years, whereas there was no difference in the other age groups. FAsCC values showed no significant changes after 2 years of age. The fiber density of the CC shows a tendency of inverse age dependence from childhood to adulthood. CONCLUSION: Rapid ongoing changes in brain maturation (increase in FAgCC) are detectable until 5 years of age. DTI reveals more information about brain maturation than T2 relaxometry.