Global and local gray matter loss in mild cognitive impairment and Alzheimer's disease.

PURPOSE: Mild cognitive impairment (MCI) is thought to be the prodromal phase to Alzheimer's disease (AD). We analyzed patterns of gray matter (GM) loss to examine what characterizes MCI and what determines the difference with AD. MATERIALS AND METHODS: Thirty-three subjects with AD, 14 normal elderly controls (NCLR), and 22 amnestic MCI subjects were included and underwent brain MR imaging. Global GM volume was assessed using segmentation and local GM volume was assessed using voxel-based morphometry (VBM); VBM was optimized for template mismatch and statistical mass. RESULTS: AD subjects had significantly (12.3%) lower mean global GM volume when compared to controls (517 +/- 58 vs. 590 +/- 52 ml; P < 0.001). Global GM volume in the MCI group (552 +/- 52) was intermediate between these two: 6.2% lower than AD and 6.5% higher than the controls but not significantly different from either group. VBM showed that subjects with MCI had significant local reductions in gray matter in the medial temporal lobe (MTL), the insula, and thalamus compared to NCLR subjects. By contrast, when compared to subjects with AD, MCI subjects had more GM in the parietal association areas and the anterior and the posterior cingulate. CONCLUSION: GM loss in the MTL characterizes MCI, while GM loss in the parietal and cingulate cortices might be a feature of AD.

A comprehensive study of gray matter loss in patients with Alzheimer's disease using optimized voxel-based morphometry.

Voxel-based morphometry (VBM) has already been applied to MRI scans of patients with Alzheimer's disease (AD). The results of these studies demonstrated atrophy of the hippocampus, temporal pole, and insula, but did not describe any global brain changes or atrophy of deep cerebral structures. We propose an optimized VBM method, which accounts for these shortcomings. Additional processing steps are incorporated in the method, to ensure that the whole spectrum of brain atrophy is visualized. A local group template was created to avoid registration bias, morphological opening was performed to eliminate cerebrospinal fluid voxel misclassifications, and volume preserving modulation was used to correct for local volume changes. Group differences were assessed and thresholded at P < 0.05 (corrected). Our results confirm earlier findings, but additionally we demonstrate global cortical atrophy with sparing of the sensorimotor cortex, occipital poles, and cerebellum. Moreover, we show atrophy of the caudate head nuclei and medial thalami. Our findings are in full agreement with the established neuropathological descriptions, offering a comprehensive view of atrophy patterns in AD.

Factor V leiden and prothrombin G20210A mutations, but not methylenetetrahydrofolate reductase C677T, are associated with recurrent miscarriages.

The aim of this study was to investigate the relationship between recurrent miscarriages and factor V Leiden, prothrombin G20210A and C677T methylenetetrahydrofolate reductase (MTHFR) mutations. In this case-control study the prevalence of factor V Leiden, prothrombin G20210A and C677T methylenetetrahydrofolate reductase mutations was determined in a consecutive series of 80 recurrent miscarriage patients and 100 controls. Fifteen of 80 recurrent miscarriage patients and four out of 100 controls carried the factor V Leiden mutation (19 versus 4%, P = 0.003, odds ratio 5.5, 95% confidence interval (CI): 1.7-17). Seven of 80 recurrent miscarriage patients and two of 100 controls were carriers of the prothrombin G20210A mutation (9 versus 2%, P = 0.038, odds ratio 4.6, 95% CI: 0.9-23.2). Six of 80 recurrent miscarriage women and 15 of 100 controls were homozygotes for the C677T MTHFR mutation (8 versus 15%, P = 0.134, odds ratio: 0.4, 95% CI: 0.1-1.2). Our results suggest that the presence of factor V Leiden and prothrombin G20210A polymorphism, but not MTHFR C677T homozygosity, could be additional risk factors for recurrent miscarriages. Furthermore, it was suggested that the prevalence of factor V Leiden and prothrombin G20210A mutations is more prominent in second trimester, primary fetal losses and it is independent of the existence of additional pathology predisposing to recurrent fetal losses.

T1 hypointensities and axonal loss.

T1 hypointensities are lesions that are hypointense on moderately T1-weighted conventional spin-echo sequences and serve as markers of matrix destruction and axonal loss. They correlate better with clinical disability than T2-weighted images, are found in patients with progressive multiple sclerosis, and can be used as surrogate outcome measures in treatment trials.