Cerebral blood flow and vasoreactivity in aging: an arterial spin labeling study.

R F Leoni,O M Pontes-Neto,I A F Oliveira,A C Santos,I.A.F Oliveira,J P Leite

doi:10.1590/1414-431x20175670

R F Leoni, O M Pontes-Neto + Show 4 more

Open Access

https://doi.org/10.1590/1414-431x20175670

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Abstract

Regional cerebral blood flow (CBF) and cerebrovascular reactivity (CVR) in young and elderly participants were assessed using pulsed arterial spin labeling (ASL) and blood oxygenation level-dependent (BOLD) magnetic resonance imaging (MRI) techniques in combination with inhalation of CO2. Pulsed ASL and BOLD-MRI were acquired in seventeen asymptomatic volunteers (10 young adults, age: 30±7 years; 7 elderly adults, age: 64±8 years) with no history of diabetes, hypertension, and neurological diseases. Data from one elderly participant was excluded due to the incorrigible head motion. Average baseline CBF in gray matter was significantly reduced in elderly (46±9 mL·100 g-1·min-1) compared to young adults (57±8 mL·100 g-1·min-1; P=0.02). Decreased pulsed ASL-CVR and BOLD-CVR in gray matter were also observed in elderly (2.12±1.30 and 0.13±0.06 %/mmHg, respectively) compared to young adults (3.28±1.43 and 0.28±0.11 %/mmHg, respectively; P<0.05), suggesting some degree of vascular impairment with aging. Moreover, age-related decrease in baseline CBF was observed in different brain regions (inferior, middle and superior frontal gyri; precentral and postcentral gyri; superior temporal gyrus; cingulate gyri; insula, putamen, caudate, and supramarginal gyrus). In conclusion, CBF and CVR were successfully investigated using a protocol that causes minimal or no discomfort for the participants. Age-related decreases in baseline CBF and CVR were observed in the cerebral cortex, which may be related to the vulnerability for neurological disorders in aging.

Highlights

Aging has been associated with motor changes and cognitive decline that can seriously interfere with quality of life [1,2]
We investigated changes in cerebral blood flow (CBF) and blood oxygenation leveldependent (BOLD) response to CO2 using an experimental setup that minimizes participant’s discomfort, and Magnetic resonance imaging (MRI) sequences available for clinical routine
BOLD-cerebrovascular reactivity (CVR) paradigm consisted of 5 epochs of hypercapnia (14 s each) intercalated by 6 epochs of normocapnia (30 s each)

Summary

Introduction

Aging has been associated with motor changes and cognitive decline that can seriously interfere with quality of life [1,2]. Age-related cerebrovascular alterations have been reported [3,4]. The study of cerebral perfusion in advanced age is important to understand neurovascular mechanisms that underlie the reported changes and their relationship with age-related pathologies. Noninvasive assessment of cerebral blood flow (CBF) and cerebrovascular reactivity (CVR) may provide additional information about the integrity of cerebrovascular reserve. Magnetic resonance imaging (MRI) techniques, such as arterial spin labeling (ASL) and blood oxygenation leveldependent (BOLD) contrast, have been widely used in combination with vasoactive challenges to map CVR, such as acetazolamide (ACZ) administration, breath-holding test (BHT) and CO2 inhalation [5]. Because the resistance of smooth muscles of blood vessels is sensitive to regional pH variation, hypercapnia results in a decrease of cerebrovascular resistance, and global vasodilation.

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