White Matter Changes in Patients with Amnestic Mild Cognitive Impairment Detected by Diffusion Tensor Imaging

Abstract

Compared to normal aging adults, individuals with amnestic mild cognitive impairment (aMCI) have significantly increased risk for progressing into Alzheimer’s disease (AD). Autopsy studies found that most of the brains of aMCI cases showed anatomical features associated with AD pathology. The recent development of non-invasive neuroimaging technique, such as diffusion tensor imaging (DTI), makes it possible to investigate the microstructures of the cerebral white matter in vivo. We hypothesized that disrupted white matter (WM) integrity existed in aMCI. So we used DTI technique, by measuring fractional anisotropy (FA) and mean diffusivity (MD), to test the brain structures involved in patients with aMCI. DTI scans were collected from 40 patients with aMCI, and 28 normal controls (NC). Tract-based spatial statistics (TBSS) analyses of whole-brain FA and MD images in each individual and group comparisons were carried out. Compared to NC, aMCI patients showed significant FA reduction bilaterally, in the association and projection fibers of frontal, parietal, and temporal lobes, corpus callosum, bilateral corona radiation, right posterior thalamic radiation and right sagittal stratum. aMCI patients also showed significantly increased MD widespreadly in the association and projection fibers of frontal, parietal and temporal lobes, and corpus callosum. Assessment of the WM integrity of the frontal, parietal, temporal lobes, and corpus callosum by using DTI measures may aid early diagnosis of aMCI.

Mild Cognitive Impairment is Associated With White Matter Integrity Changes in Late-Myelinating Regions Within the Corpus Callosum

“…It is often assumed that the genu is later-myelinating relative to the splenium due to the general tendency of frontal regions to myelinate later than posterior regions (Kinney et al, 1988) and the predominance of fibers connecting prefrontal regions in the genu, versus temporoparietal fibers in the splenium (Lebel et al, 2010; Preti et al, 2012). Decreased white matter integrity within the corpus callosum has been previously reported in patients with AD relative to healthy controls (Alves et al, 2012; Duan et al, 2006; Hanyu et al, 1999; Naggara et al, 2006; Parente et al, 2008; Preti et al, 2012; Takahashi et al, 2002; Teipel, 2007; Teipel et al, 2012) and MCI (Alves et al, 2012; Delano-Wood et al, 2008; Di Paola et al, 2010a; Fellgiebel et al, 2004; Liu et al, 2013; Scrascia et al, 2014; Ukmar et al, 2008; Wang et al, 2009; Wang et al, 2014; Xie et al, 2006). However, inconsistencies exist in the literature base regarding the location of abnormalities within the corpus callosum, when changes emerge across the disease course and the underlying mechanisms driving the changes.…”

Magnetic resonance imaging of leukoencephalopathy in amnestic workers exposed to organotin

“…There is a growing body of evidence suggesting that active white matter degeneration underlies amnestic mild cognitive impairment (Rowley et al, 2013, Chen et al, 2009Gouw et al, 2008;Duan et al, 2006;Liu et al, 2013).…”

Longitudinal Magnetic Resonance Imaging (MRI) Analysis of the Developmental Changes of Tourette Syndrome Reveal Reduced Diffusion in the Cortico-Striato-Thalamo-Cortical Pathways

“…50,51 In patients with mild cognitive impairment and ADHD, there have been, among others, findings of altered white matter integrity in thalamic radiation. 52,53 In patients with obsessive compulsive disorder, white matter abnormalities were, among others, seen in the orbitofrontal-striatothalamo-cortical circuit. 54,55 Asymmetry…”