Application of cerebral MR perfusion imaging using pulsed arterial spin labeling technique in patients with amnestic-type mild cognitive impairment and mild Alzheimer disease

Abstract

Objective To study the value of relative cerebral blood flow (rCBF) changes in patients with amnestic-type mild cognitive impairment (aMCI) and mild Alzheimer disease (AD) using MRI pulsed arterial spin labeling (PASL). Methods A prospective study recruited 37 aMCI patients (aMCI group) , 30 mild AD patients (mild AD group) and 30 healthy volunteers (normal control group) from March 2011 to December 2013, MRI using PASL for cerebral perfusion imaging was performed and data of rCBF were collected. Taking age as covariate, analysis of variance (ANONA) was carried out to assess the difference of rCBF among all the three groups, then Bonferroni was done between every two groups. A follow-up examination using PASL was performed in the seventeen patients of the aMCI group. And paired t-test was used for comparing the longitudinal change of their rCBF data. Results Compared with the normal control group, the aMCI group showed significant increase of rCBF in bilateral posterior cingulate cortices and precuneus (cluster number 2 785, P<0.05). While the mild AD group showed decrease of rCBF in the left inferior and superior parietal lobes, the angular, middle frontal lobe, as well as the right superior temporal lobe (cluster number 3 459-5 206, P<0.05). When compared with the aMCI group, the mild AD group showed regional hypoperfusion in bilateral middle frontal lobes, the left precuneus, the right postcentral and inferior parietal lobe (cluster number 3 236-19 863, P<0.05). In the longitudinal study of the 17 aMCI patients, an increased rCBF was found to coexist with reduced rCBF in the left inferior frontal and lateral occipital cortex, bilateral frontal poles and paracingulate gyrus, with hyperperfusion dominated. Increased rCBF was also detected in the left temporal lobe, the angular gyrus and precuneus, while decreased rCBF was present in the left putamen, the operculum and right corpus callosum (P<0.05). Conclusions ASL perfusion imaging is a valuable method for dynamic monitoring of the cerebral perfusion changes in aMCI and AD patients. PASL will assist in finding a useful imaging biomarker for early diagnosis of AD. Key words: Cognition disorders; Alzheimer disease; Magnetic resonance imaging