Cerebral Blood Flow Measured with 3D Pseudocontinuous Arterial Spin-labeling MR Imaging in Alzheimer Disease and Mild Cognitive Impairment: A Marker for Disease Severity

Purpose: To compare quantitative cerebral blood flow (CBF) values in patients with Alzheimer disease (AD), patients with mild cognitive impairment (MCI), and subjects with subjective complaints by using a whole-brain three-dimensional (3D) pseudocontinuous arterial spin-labeling (ASL) technique at 3.0 T. Materials and Methods: The local institutional review board approved the study. All subjects provided informed consent. Whole-brain 3D fast spin-echo pseudocontinuous ASL images were acquired at 3.0 T in 71 patients with AD (mean age, 65 years +/- 7; 55% women), 35 patients with MCI (mean age, 65 years +/- 8; 42% women), and 73 subjects with subjective complaints (mean age, 60 years +/- 9; 39% women) who visited a memory clinic. Analyses were performed by using both uncorrected maps and maps corrected for partial volume effects. Regional CBF was compared by using analyses of variance; permutation tests were used for voxel-wise comparisons. Associations with cognition (Mini-Mental State Examination) were investigated by using linear regression analyses. All analyses were corrected for age and sex. Results: Uncorrected CBF was decreased in patients with AD compared with subjects with subjective complaints (27 mL/100 g/min +/- 5 vs 33 mL/100 g/min +/- 5; P < .001), with strongest reductions in the parietal lobes (22 mL/100 g/min +/- 6 vs 30 mL/100 g/min +/- 5; ie, decrease of 27%). Corrected cortical CBF showed similar results. In patients with MCI, CBF was decreased in the precuneus and the parietal and occipital lobes compared with subjects with subjective complaints. Voxel-wise comparisons confirmed the region of interest-based findings, showing the largest CBF differences in the precuneus and bilateral parietal cortex. Uncorrected and corrected cortical CBF were associated with cognition across diagnostic groups (beta = 0.46 and beta = 0.42, P < .001) and within the AD group (beta = 0.41 and beta = 0.42, P < .001). Conclusion: CBF measured with 3D pseudocontinuous ASL MR imaging helps detect functional changes in the prodromal and more advanced stages of AD and is a marker for disease severity. (C)RSNA, 2012