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Functional magnetic resonance imaging detection of vascular reactivity in cerebral amyloid angiopathy.

ABSTRACT: In addition to its role in hemorrhagic stroke, advanced cerebral amyloid angiopathy (CAA) is also associated with ischemic lesions and vascular cognitive impairment. We used functional magnetic resonance imaging (MRI) techniques to identify CAA-associated vascular dysfunction.Functional MRI was performed on 25 nondemented subjects with probable CAA (mean ± standard deviation age, 70.2 ± 7.8 years) and 12 healthy elderly controls (age, 75.3 ± 6.2 years). Parameters measured were reactivity to visual stimulation (quantified as blood oxygen level-dependent [BOLD] response amplitude, time to peak response, and time to return to baseline after stimulus cessation) and resting absolute cerebral blood flow in the visually activated region (measured by arterial spin labeling).CAA subjects demonstrated reduced response amplitude (percentage change in BOLD signal, 0.65 ± 0.28 vs 0.89 ± 0.14; p < 0.01), prolonged time to peak (11.1 ± 5.1 vs 6.4 ± 1.8 seconds; p < 0.001), and prolonged time to baseline (16.5 ± 6.7 vs 11.6 ± 3.1 seconds; p < 0.001) relative to controls. These differences were independent of age, sex, and hypertension in multivariable analysis and were also present in secondary analyses excluding nonresponsive voxels or voxels containing chronic blood products. Within the CAA group, longer time to peak correlated with overall volume of white matter T2 hyperintensity (Pearson correlation, 0.53; p = 0.007). Absolute resting blood flow in visual cortex, in contrast, was essentially identical between the groups (44.0 ± 12.6 vs 45.0 ± 10.0 ml/100 g/min, p = 0.8).Functional MRI identifies robust differences in both amplitude and timing of the response to visual stimulation in advanced CAA. These findings point to potentially powerful approaches for identifying the mechanistic links between vascular amyloid deposits, vascular dysfunction, and CAA-related brain injury.

SUBMITTER: Dumas A

PROVIDER: S-EPMC3408630 | biostudies-literature | 2012 Jul

REPOSITORIES: biostudies-literature

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Functional magnetic resonance imaging detection of vascular reactivity in cerebral amyloid angiopathy.

Dumas Andrew A Dierksen Gregory A GA Gurol M Edip ME Halpin Amy A Martinez-Ramirez Sergi S Schwab Kristin K Rosand Jonathan J Viswanathan Anand A Salat David H DH Polimeni Jonathan R JR Greenberg Steven M SM

Annals of neurology 20120701 1

<h4>Objective</h4>In addition to its role in hemorrhagic stroke, advanced cerebral amyloid angiopathy (CAA) is also associated with ischemic lesions and vascular cognitive impairment. We used functional magnetic resonance imaging (MRI) techniques to identify CAA-associated vascular dysfunction.<h4>Methods</h4>Functional MRI was performed on 25 nondemented subjects with probable CAA (mean ± standard deviation age, 70.2 ± 7.8 years) and 12 healthy elderly controls (age, 75.3 ± 6.2 years). Paramete ...[more]

PMID: 22829269

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Project description:Cerebral amyloid angiopathy (CAA) involves cerebrovascular amyloid deposition and is classified into several types according to the amyloid protein involved. Of these, sporadic amyloid β-protein (Aβ)-type CAA is most commonly found in older individuals and in patients with Alzheimer's disease (AD). Cerebrovascular Aβ deposits accompany functional and pathological changes in cerebral blood vessels (CAA-associated vasculopathies). CAA-associated vasculopathies lead to development of hemorrhagic lesions [lobar intracerebral macrohemorrhage, cortical microhemorrhage, and cortical superficial siderosis (cSS)/focal convexity subarachnoid hemorrhage (SAH)], ischemic lesions (cortical infarction and ischemic changes of the white matter), and encephalopathies that include subacute leukoencephalopathy caused by CAA-associated inflammation/angiitis. Thus, CAA is related to dementia, stroke, and encephalopathies. Recent advances in diagnostic procedures, particularly neuroimaging, have enabled us to establish a clinical diagnosis of CAA without brain biopsies. Sensitive magnetic resonance imaging (MRI) methods, such as gradient-echo T2(*) imaging and susceptibility-weighted imaging, are useful for detecting cortical microhemorrhages and cSS. Amyloid imaging with amyloid-binding positron emission tomography (PET) ligands, such as Pittsburgh Compound B, can detect CAA, although they cannot discriminate vascular from parenchymal amyloid deposits. In addition, cerebrospinal fluid markers may be useful, including levels of Aβ40 for CAA and anti-Aβ antibody for CAA-related inflammation. Moreover, cSS is closely associated with transient focal neurological episodes (TFNE). CAA-related inflammation/angiitis shares pathophysiology with amyloid-related imaging abnormalities (ARIA) induced by Aβ immunotherapies in AD patients. This article reviews CAA and CAA-related disorders with respect to their epidemiology, pathology, pathophysiology, clinical features, biomarkers, diagnosis, treatment, risk factors, and future perspectives.

Dataset Information

Functional magnetic resonance imaging detection of vascular reactivity in cerebral amyloid angiopathy.

Publications

Functional magnetic resonance imaging detection of vascular reactivity in cerebral amyloid angiopathy.

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