Divergent regional patterns of cerebral hypoperfusion and gray matter atrophy in mild cognitive impairment patients

Abstract

Reductions of cerebral blood flow and gray matter structure have been implicated in early pathogenesis of Alzheimer's disease, potentially providing complementary information. The present study evaluated regional patterns of cerebral hypoperfusion and atrophy in patients with mild cognitive impairment and healthy older adults. In each participant, cerebral perfusion and gray matter structure were extracted within selected brain regions vulnerable to Alzheimer's disease using magnetic resonance imaging. Measures were compared between diagnostic groups with/without adjustment for covariates. In mild cognitive impairment patients, cerebral blood flow was significantly reduced in comparison with healthy controls in temporo-parietal regions and the basal ganglia in the absence of local gray matter atrophy. By contrast, gray matter structure was significantly reduced in the hippocampus in the absence of local hypoperfusion. Both, cerebral perfusion and gray matter structure were significantly reduced in the entorhinal and isthmus cingulate cortex in mild cognitive impairment patients compared with healthy older adults. Our results demonstrated partly divergent patterns of temporo-parietal hypoperfusion and medial-temporal atrophy in mild cognitive impairment patients, potentially indicating biomarker sensitivity to dissociable pathological mechanisms. The findings support applicability of cerebral perfusion and gray matter structure as complementary magnetic resonance imaging-based biomarkers in early Alzheimer's disease detection, a hypothesis to be further evaluated in longitudinal studies.

Keywords: Alzheimer’s disease; Cerebral blood flow; cerebral blood volume; magnetic resonance imaging; mild cognitive impairment.

Figures

Figure 1.

Representation of the AD-related regions-of-interest. Three-dimensional representation of cortical AD-related regions-of-interest (ROIs). The ROIs are projected on the gray matter surface of the left hemisphere. Subcortical ROIs of the hippocampus and basal ganglia are not shown.

Figure 2.

Effects of diagnostic group on perfusion and structural MRI measures. Effects of diagnostic group (HC, MCI) on cerebral blood volume (first bar), cerebral blood flow (second bar), gray matter volume (third bar), or cortical thickness (fourth bar) for AD-related regions-of-interest (ROIs). Negative standardized beta coefficients reflect biomarkers reductions in MCI patients; statistical significance is indicated (*p