RESUMEN
BACKGROUND/AIMS: Atrophy in both grey and white matter is found in normal aging. The prefrontal cortex and the frontal lobe white matter are thought to be the most affected regions. Our aim was to examine the effects of normal aging on cortical grey matter using a 3D quantitative cortical mapping method. METHODS: We analyzed 1.5-tesla brain magnetic resonance imaging data from 44 cognitively normal elderly subjects using cortical pattern matching and cortical thickness analyses. Linear regression analysis was used to study the effect of age on cortical thickness. 3D map-wide correction for multiple comparisons was conducted with permutation analyses using a threshold of p < 0.01. RESULTS: We found a significant negative association between age and cortical thickness in the right hemisphere (pcorrected = 0.009) and a trend level association in the left hemisphere (pcorrected = 0.081). Age-related changes were greatest in the sensorimotor, bilateral dorsal anterior cingulate and supplementary motor cortices, and the right posterior middle and inferior frontal gyri. Age effects greater in the medial than lateral visual association cortices were also seen bilaterally. CONCLUSION: Our novel method further validates that normal aging results in diffuse cortical thinning that is most pronounced in the frontal and visual association cortices.
RESUMEN
We applied the hippocampal radial atrophy mapping technique to the baseline and follow-up magnetic resonance image data of 169 amnestic mild cognitive impairment (MCI) participants in the imaging arm of the Alzheimer's Disease Cooperative Study MCI Donepezil/Vitamin E trial. Sixty percent of the subjects with none to mild hippocampal atrophy rated with the visual medial temporal atrophy rating scale (MTA score < 2) and 33.8% of the subjects with moderate to severe (MTA > or = 2) hippocampal atrophy converted to Alzheimer's disease (AD) during 3-year follow-up. MTA > or = 2 showed a trend for greater left sided hippocampal atrophy versus MTA < 2 groups at baseline (P(corrected) = 0.08). Higher MTA scores were associated with progressive atrophy of the subiculum and the CA1-3 subregions. The MTA < 2 group demonstrated significant bilateral atrophy progression at follow-up (left P(corrected) = 0.008; right P(corrected) = 0.05). Relative to MTA < 2 nonconverters, MTA < 2 converters showed further involvement of the subiculum and CA1 and additional involvement of CA2-3 at follow-up. Right CA1 atrophy was significantly associated with conversion to dementia (for 1 mm greater right CA1 radial distance subjects had 50% reduced hazard for conversion). Greater CA1 and subicular atrophy can be demonstrated early and is predictive of future conversion to AD, whereas CA2-3 involvement becomes more evident as the disease progresses.
Asunto(s)
Enfermedad de Alzheimer/patología , Trastornos del Conocimiento/patología , Hipocampo/patología , Anciano , Enfermedad de Alzheimer/tratamiento farmacológico , Atrofia , Trastornos del Conocimiento/tratamiento farmacológico , Progresión de la Enfermedad , Femenino , Estudios de Seguimiento , Lateralidad Funcional , Humanos , Imagenología Tridimensional , Estudios Longitudinales , Imagen por Resonancia Magnética , Masculino , Nootrópicos/uso terapéutico , Índice de Severidad de la Enfermedad , Vitamina E/uso terapéuticoRESUMEN
PURPOSE: The aim of this study was to investigate the longitudinal positron emission tomography (PET) metabolic changes in the elderly. PROCEDURES: Nineteen nondemented subjects (mean Mini-Mental Status Examination 29.4 +/- 0.7 SD) underwent two detailed neuropsychological evaluations and resting 2-deoxy-2-[F-18]fluoro-D: -glucose (FDG)-PET scan (interval 21.7 +/- 3.7 months), baseline structural 3T magnetic resonance (MR) imaging, and apolipoprotein E4 genotyping. Cortical PET metabolic changes were analyzed in 3-D using the cortical pattern matching technique. RESULTS: Baseline vs. follow-up whole-group comparison revealed significant metabolic decline bilaterally in the posterior temporal, parietal, and occipital lobes and the left lateral frontal cortex. The declining group demonstrated 10-15% decline in bilateral posterior cingulate/precuneus, posterior temporal, parietal, and occipital cortices. The cognitively stable group showed 2.5-5% similarly distributed decline. ApoE4-positive individuals underwent 5-15% metabolic decline in the posterior association cortices. CONCLUSIONS: Using 3-D surface-based MR-guided FDG-PET mapping, significant metabolic changes were seen in five posterior and the left lateral frontal regions. The changes were more pronounced for the declining relative to the cognitively stable group.