Voxel-wise correlations between cognition and cerebral blood flow using arterial spin-labeled perfusion MRI in patients with Alzheimer’s disease: a cross-sectional study

BACKGROUND: To analyze voxel-wise correlation between cerebral blood flow (CBF) measured using ASL-MRI and cognition in patients with Alzheimer’s disease (AD). METHODS: Forty-one patients diagnosed with AD or mild cognitive impairment due to AD were recruited for this study. CBF images were obtained using ASL-MRI (n = 41) with a post-labeling delay (PLD) of 1.5 and 2.5 s (PLD(1.5) and PLD(2.5), respectively) using a 3 T scanner, in addition to brain perfusion SPECT with N-isopropyl-4-[I-123]iodoamphetamine (n = 28). Voxel-based analyses were performed for ASL-MRI and SPECT using Mini-Mental State Examination (MMSE) scores as covariates. Differences in CBF between PLD(1.5) and PLD(2.5) were assessed using a paired t-test with SPM12. RESULTS: Significant positive correlations were observed between MMSE scores and CBF at PLD(1.5) in the right posterior cingulate cortex (PCC), and both temporo-parietal association cortexes. At PLD(2.5), significant positive correlations were determined for MMSE scores and CBF in the superior parietal lobule and the right temporo-parietal association cortex. SPECT showed significant positive correlations in the PCC and both temporo-parietal association cortexes (right-side dominant). PLD(1.5) showed significantly higher CBF than PLD(2.5) in the proximal areas of vascular territories of the anterior, middle, and posterior cerebral arteries. CONCLUSIONS: Significant positive correlations in CBF, measured with both ASL-MRI and SPECT, with cognition were found in the PCC and temporo-parietal association cortexes. PLD(1.5) and PLD(2.5) showed similar correlations with cognition, although the CBF images had significant differences.