MR imaging texture analysis of the corpus callosum and thalamus in amnestic mild cognitive impairment and mild Alzheimer disease.

BACKGROUND AND PURPOSE: TA is a branch of image processing that seeks to reduce image information by extracting texture descriptors from the image. TA of MR images of anatomic structures in mild AD and aMCI is not well-studied. Our objective was to attempt to find differences among patients with aMCI and mild AD and normal-aging subjects, by using TA applied to the MR images of the CC and the thalami of these groups of subjects. MATERIALS AND METHODS: TA was applied to the MR images of 17 patients with aMCI, 16 patients with mild AD, and 16 normal-aging subjects. The TA approach was based on the GLCM. MR images were T1-weighted and were obtained in the sagittal and axial planes. The CC and thalami were manually segmented for each subject, and 44 texture parameters were computed for each of these structures. RESULTS: TA parameters showed differences among the 3 groups for the CC and thalamus. A pair-wise comparison among groups showed differences for AD-control and aMCI-AD for the CC; and for AD-control, aMCI-AD, and aMCI-control for the thalamus. CONCLUSIONS: TA is a useful technique to aid in the detection of tissue alterations in MR images of mild AD and aMCI and has the potential to become a helpful tool in the diagnosis and understanding of these pathologies.

Relationship between environmental factors and gray matter atrophy in refractory MTLE.

OBJECTIVE: To investigate clinical, neuropsychological, and MRI abnormalities (gray matter atrophy [GMA] and white matter atrophy [WMA]) in surgical mesial temporal lobe epilepsy (MTLE) patients with and without familial antecedent for epilepsy. METHODS: A cohort study including 69 operated patients with unilateral MTLE, divided into a group of 29 patients (mean age 35.8 +/- 10.4 years) with a negative family history (FH) of epilepsy and a group of 40 patients (32.8 +/- 10 years) with a positive FH. We performed voxel-based morphometry (VBM) on preoperative MRIs and investigated possible clinical and neuropsychological differences between the 2 groups. We also performed VBM and t tests to compare the patients' groups with normal controls. RESULTS: The negative-FH group had lower IQ scores (p = 0.004), performed poorer on the Boston Naming Test (p = 0.02) and on delayed recall (p = 0.03), and presented a more prominent asymmetry index of hippocampal volume (p = 0.04) and more frequent initial precipitating injuries (p = 0.023). VBM showed a more restricted pattern of GMA in the positive-FH group and a more bilateral and widespread pattern of GMA in the negative-FH group, involving thalami, temporal, frontal, parietal, and occipital lobes. WMA was widespread and bilateral in both groups. CONCLUSIONS: The more widespread structural voxel-based morphometry abnormalities and worse IQ performance identified in the negative-family history (FH) group may result from a stronger environmental influence, including initial precipitating injuries. This is further support for the hypothesis that hippocampal sclerosis in mesial temporal lobe epilepsy with positive FH is determined by a stronger genetic predisposition with less influence of environmental factors compared with patients in the negative-FH group.

Differences in grey and white matter atrophy in amnestic mild cognitive impairment and mild Alzheimer's disease.

BACKGROUND: Grey matter (GM) atrophy has been demonstrated in amnestic mild cognitive impairment (aMCI) and mild Alzheimer's disease (AD), but the role of white matter (WM) atrophy has not been well characterized. Despite these findings, the validity of aMCI concept as prodromal AD has been questioned. METHODS: We performed brain MRI with voxel-based morphometry analysis in 48 subjects, aiming to evaluate the patterns of GM and WM atrophy amongst mild AD, aMCI and age-matched normal controls. RESULTS: Amnestic mild cognitive impairment GM atrophy was similarly distributed but less intense than that of mild AD group, mainly in thalami and parahippocampal gyri. There were no difference between aMCI and controls concerning WM atrophy. In the mild AD group, we found WM atrophy in periventricular areas, corpus callosum and WM adjacent to associative cortices. DISCUSSION: We demonstrated that aMCI might be considered a valid concept to detect very early AD pathology, since we found a close proximity in the pattern of atrophy. Also, we showed the involvement of WM in mild AD, but not in aMCI, suggesting a combination of Wallerian degeneration and microvascular ischaemic disease as a plausible additional pathological mechanism for the discrimination between MCI and AD.

Focal status epilepticus as the first manifestation of paracoccidioidomycosis.

We report a 56-year old man with prolonged focal motor status epilepticus as the first clinical manifestation of paracoccidioidomycosis (PCM) and discuss this unusual presentation. We emphasize the need for a comprehensive work-up and increased awareness for central nervous system involvement in PCM, particularly in endemic areas.