Vascular brain lesions, brain atrophy, and cognitive decline. The Second Manifestations of ARTerial disease—Magnetic Resonance (SMART-MR) study

We investigated whether total cerebral blood flow (CBF) was associated with brain atrophy, and whether this relation was modified by white matter lesions (WML). Within the Second Manifestations of ARTerial disease-magnetic resonance (SMART-MR) study, a prospective cohort study among patients with arterial disease, cross-sectional analyses were performed in 828 patients (mean age 58±10 years, 81% male) with quantitative flow, atrophy, and WML measurements on magnetic resonance imaging (MRI). Total CBF was measured with MR angiography and was expressed per 100 mL brain volume. Total brain volume and ventricular volume were divided by intracranial volume to obtain brain parenchymal fraction (BPF) and ventricular fraction (VF). Lower BPF indicates more global brain atrophy, whereas higher VF indicates more subcortical brain atrophy. Mean CBF was 52.0±10.2 mL/min per 100 mL, mean BPF was 79.2±2.9%, and mean VF was 2.03±0.96%. Linear regression analyses showed that lower CBF was associated with more subcortical brain atrophy, after adjusting for age, sex, vascular risk factors, intima-media thickness, and lacunar infarcts, but only in patients with moderate to severe WML (upper quartile of WML): Change in VF per s.d. decrease in CBF 0.18%, 95% CI: 0.02 to 0.34%. Our findings suggest that cerebral hypoperfusion in the presence of WML may be associated with subcortical brain atrophy.

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Reduced parenchymal cerebral blood flow is associated with greater progression of brain atrophy: The SMART-MR study

Journal of Cerebral Blood Flow & Metabolism ◽

10.1177/0271678x20948614 ◽

2020 ◽

pp. 0271678X2094861

Author(s):

Rashid Ghaznawi ◽

Maarten HT Zwartbol ◽

Nicolaas PA Zuithoff ◽

Jeroen de Bresser ◽

Jeroen Hendrikse ◽

...

Keyword(s):

Blood Flow ◽

Cerebral Blood Flow ◽

Brain Atrophy ◽

Brain Volume ◽

Arterial Disease ◽

Cerebral Hypoperfusion ◽

Intracranial Volume ◽

Total Brain Volume ◽

Brain Parenchymal ◽

Mr Study

Global cerebral hypoperfusion may be involved in the aetiology of brain atrophy; however, long-term longitudinal studies on this relationship are lacking. We examined whether reduced cerebral blood flow was associated with greater progression of brain atrophy. Data of 1165 patients (61 ± 10 years) from the SMART-MR study, a prospective cohort study of patients with arterial disease, were used of whom 689 participated after 4 years and 297 again after 12 years. Attrition was substantial. Total brain volume and total cerebral blood flow were obtained from magnetic resonance imaging scans and expressed as brain parenchymal fraction (BPF) and parenchymal cerebral blood flow (pCBF). Mean decrease in BPF per year was 0.22% total intracranial volume (95% CI: –0.23 to –0.21). Mean decrease in pCBF per year was 0.24 ml/min per 100 ml brain volume (95% CI: –0.29 to –0.20). Using linear mixed models, lower pCBF at baseline was associated with a greater decrease in BPF over time ( p = 0.01). Lower baseline BPF, however, was not associated with a greater decrease in pCBF ( p = 0.43). These findings indicate that reduced cerebral blood flow is associated with greater progression of brain atrophy and provide further support for a role of cerebral blood flow in the process of neurodegeneration.

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