Voxel-based morphometry to discriminate early Alzheimer's disease from controls

University of Tsukuba, Tsukuba, Ibaraki, Japan
Neuroscience Letters (Impact Factor: 2.03). 08/2005; 382(3):269-74. DOI: 10.1016/j.neulet.2005.03.038
Source: PubMed


We assessed the accuracy of voxel-based morphometry (VBM) using a three-dimensional T1-weighted MRI in discriminating Alzheimer's disease (AD) in the very early stage of amnestic type of mild cognitive impairment and age-matched healthy controls. We randomly divided these subjects into two groups. The first group comprising 30 AD patients and 41 controls was used to identify the area with the most significant gray matter loss in patients compared to normal controls based on the voxel-based analysis of a group comparison. The second group comprising 31 patients and 41 controls was used to determine the discrimination accuracy of VBM. A Z-score map for a gray matter image of a subject was obtained by comparison with mean and standard deviation gray matter images of the controls for each voxel after anatomical standardization and voxel normalization to global mean using the following equation; Z-score=([control mean]-[individual value])/(control S.D.). Receiver operating characteristic curves for a Z-score in the bilateral medial temporal areas including the entorhinal cortex with the most significant loss in the first group showed a high discrimination accuracy of 87.8%. This result would open up a possibility for early diagnosis of AD using VBM.

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Available from: Kiyotaka Nemoto, Jul 02, 2015
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    • "Then, gray matter images were smoothed with an isotropic Gaussian kernel with a full-width-at-half-maximum of 12 mm. We compared the gray matter images of each subject with the mean and standard deviation of gray matter images obtained from healthy older adults using voxel-by-voxel Z-score analysis (Hirata et al., 2005; Matsuda et al., 2012). Regions of brain atrophy were defined as voxels with a Z-score N 2. A brain atrophy index was defined as the proportion of atrophic voxels relative to the total number of voxels for the entire brain. "
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    • "Although the amyloid and tau imaging methods enable direct observation of AD pathogenesis, they are not appropriate methods for easily screening dementia in most hospitals and are still not easily applied in clinical practice. In that regard, VBM-MRI that could detect AD-specific structural brain changes, especially medial temporal atrophy (MTA) [8] [9] [10] [11], and magnetic resonance spectroscopy ( 1 H MRS) using regular 1.5-Tesla (T) MRI that captures early brain biochemical abnormalities, are popular, non-invasive, cost-effective, require a short examination time, and are practical for early diagnosis and for tracking subjects with dementia due to AD [19] [20] [21] [22] [23] [24] [25] [26] [27] [28] [29] [30] [31] [32]. Previous studies have shown the utility of VBM-MRI for showing MTA and metabolite abnormalities on 1 H MRS for the early diagnosis of MCI and AD [8–11, 19–33]. "

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    • "At the very early stage of AD, regional cortical atrophy is mainly restricted to the medial temporal structures as well as the posterior cingulate gyrus [44,45,46]. With the progression of the disease, the atrophic areas extend to the parietal and frontal lobes with the advancement of the disease [47,48]. "
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