Alzheimer disease (AD) is a neurodegenerative process affecting memory and cognition in the elderly. Hypertension (HTN), another disease that increases in prevalence with aging, is hypothesized to mediate decreased cerebral perfusion in AD. We investigated this question using arterial spin labeled (ASL) MRI.
METHOD AND MATERIALS
48 control normals (38 no HTN:10 with) and , 20 AD (10 with/without), and 20 MCI (10 with/without) were recruited from the CHS-CS (Cardiovascular Health Study—Cognition Study) and were scanned with T1W MR and ASL at 1.5 T. All scans were voxel warped to a standard colin27 brain. Statistical parametric mapping (SPM2—Wellcome Boroughs) analyzed rCBF on a voxel per voxel basis to evaluate for rCBF deviation in regions involved with memory and cognition.
rCBF is substantially decreased in patients with HTN compared to those without in CN, AD, and MCI groups. Overall rCBF is lowest in AD with HTN (34.8 ml/100g/min) compared to CN with HTN (41.43) and MCI with HTN (47.75). Most notably decreased flow in AD occurs in the posterior cingulate (35.9), prefrontal cortex (29.5), and the thalamus (28.9).
Presence of HTN, treated or untreated, is associated with decreased cerebral perfusion in CN, AD, and MCI groups. Magnitude of perfusion decrease was largest in AD. These data suggest that HTN could contribute to the pathology of AD through affects on rCBF.
HTN can be linked to changes in rCBF in AD. This phenomenon can be studied using ASL, a non-invasive technique that uses no external contrast and is cost effective relative to other modalities.