Cerebral blood flow by arterial spin labeling in poststroke dementia

Abstract

Objective: To investigate the relationship between cerebral blood flow and dementia in older stroke survivors and subjects with Alzheimer disease (AD). Methods:This cohort study used arterial spin labeling MRI at 3 T to examine cerebral blood flow (CBF).We scanned 39 patients 6 years after stroke. They were older than 75 years at the time of stroke and free of dementia 3 months poststroke, with 8 subsequently developing dementia. We also scanned 17 subjects with AD and 29 healthy control subjects. We determined the perfusion in regions of interest (ROIs). Hippocampal volume was also measured using a previously validated automated procedure. Results:The gray matter/white matter CBF ratio was reduced globally in the poststroke dementia (PSD) group (1.55 SD ϭ 0.12) relative to control subjects (1.78 SD ϭ 0.18; p ϭ 0.03). The CBF ratio in a parietal ROI was reduced in the AD (1.34 SD ϭ 0.31; p ϭ 0.003), PSD (1.32 SD ϭ 0.22; p ϭ 0.041), and poststroke no-dementia (PSND) (1.44 SD ϭ 0.34; p ϭ 0.014) groups relative to that of control subjects (1.70 SD ϭ 0.32). In subjects without stroke, the best predictor of dementia was hippocampus volume, whereas in the stroke group, it was the global CBF gray matter/white matter ratio. Hippocampus volume was not significantly different between the AD and PSD groups, and both had reduced hippocampi relative to those of control subjects and the PSND group. Conclusions:We found evidence for both vascular and AD pathology in PSD, suggesting that both the direct impact of the stroke and subsequent development of AD-type changes play a role in the etiology of PSD. Neurology Dementia is common in people with stroke and may be preexisting in 10% of subjects and a direct consequence of the stroke in a further 15%.1 However, stroke is also a risk factor for dementia in the long term.

Temporal and Spatial Variances in Arterial Spin-Labeling Are Inversely Related to Large-Artery Blood Velocity

“…The GM-CBF values observed here are consistent with those in other studies involving younger adults, 27 healthy older adults, 28 and individuals with chronic stroke. 29 Older adults with WMH, however, exhibited lower GM-CBF than previously reported. 30 Calibration of the GM-CBF to individual labeling efficiency on the basis of PC altered the sensitivity to distinguish clinical groups.…”

Staging and natural history of cerebrovascular pathology in dementia

“…27 In our more recent study on poststroke stable and dementia cases there was also no major impact on laterality of medial temporal atrophy or hippocampal microscopic changes. 28 In agreement with the harmonization standards, 6 we recommend that alternate sampling should be now widely used in prospective cohorts. We recognize, however, that even the limited number of brain regions we studied may exceed available resources on a clinical neuropathologic service.…”

Intensive Blood Pressure Lowering Increases Cerebral Blood Flow in Older Subjects With Hypertension

“…[12][13][14] It has also been suggested that hypotension resulting from BP-lowering drugs may be more harmful than hypertension in older people with hypoperfusion producing syncope, falls, and possibly accelerating atrophy and leukoaraiosis. 15 Cognitive decline is associated with reduced CBF in the elderly, 16 and we have shown reductions in CBF are associated with poststroke dementia 17 and late life depression. 18 Preventing reductions in CBF associated with hypertension in older people might reduce the risk of cognitive impairment and mood disorders.…”