ASL - MRI Cerebal Perfusion Patterns in Alzheimer's Disease

 

Aim:  To determine if cerebral blood flow (CBF) perfusion patterns from arterial spin-labeling MRI (ASL-MR) discriminate mild-moderate Alzheimer's disease (AD) from healthy older controls and act as a potential biomarker.

Methods:  Pseudo-continuous ASL-MR was used on a 3T HDx Signa GE scanner.  Seven subjects with probable AD (age=72.0±8.1 years, MMSE=19.3) and seven age-matched controls (age=70.3±6.4 years, MMSE=29.1) had MRI scans.  All subjects completed neuropsychological tests including the Mini Mental Status Examination (MMSE), Montreal Cognitive Assessment scale (MoCA) and Alzheimer Disease Assessment Scale-Cognitive subscale (ADAS-cog).  Principal Component Analysis (PCA), a method of multivariate analysis, detailed perfusion patterns of the data as principal component images. 

Results:  The first principal component explained 27% of variance and demonstrated a pattern in which the AD group showed hypo-perfusion relative to the control group in thalami, parieto-occipital, frontal and posterior cingulate cortices (p=0.0403).  Within the AD group, increased severity of impairment as indexed by the MMSE, MoCA, and ADAS-cog appeared to be linearly associated with decreased expression of the first component.  There was no relationship among the controls, who showed ceiling or floor effects for the severity measures.

Conclusions:  The pattern demonstrated in our AD group was similar to previously established hypo-perfusion patterns using PET and ASL-MR.  Our preliminary results demonstrated the ability to detect differing perfusion patterns between AD and control groups and showed signs of correlation with global cognition, even with a small sample.  The ability to non-invasively acquire a quantitative measure of CBF, give ASL-MR promise as a biomarker in AD.

 

Wright S.L.^1,2, MacAskill M.R.^1,2, Watts R.^1,3, Melzer T.R.^1,2, Keenan R.⁴, Shankaranarayanan A.⁵, Alsop D.C.⁶, Dalrymple-Alford J.C.^1,7, and Anderson T.J.^1,2

¹Van der Veer Institute for Parkinson's and Brain Research, Christchurch, New Zealand, ²Medicine, University of Otago, Christchurch, New Zealand, ³Physics and Astronomy, University of Canterbury, Christchurch, New Zealand, ⁴Christchurch Radiology Group, Christchurch, New Zealand, ⁵GE Healthcare, Menlo Park, California, United States, ⁶Beth Israel Deconess Medical Centre, Boston, MA, United States, ⁷Psychology, University of Canterbury, Christchurch, New Zealand.