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Cerebral amyloid angiopathy: emerging concepts.

Yamada M - J Stroke (2015)

Bottom Line: Cerebrovascular Aβ deposits accompany functional and pathological changes in cerebral blood vessels (CAA-associated vasculopathies).Moreover, cSS is closely associated with transient focal neurological episodes (TFNE).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.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurology and Neurobiology of Aging, Kanazawa University Graduate School of Medical Sciences, Kanazawa, Japan.

ABSTRACT
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.

No MeSH data available.


Related in: MedlinePlus

Imaging findings of CAA-related hemorrhages and white matter lesions. Fresh (arrow) and old (arrowhead) lobar macrohemorrhages in the frontal lobes on CT (A). Cortical microhemorrhages with lobar distribution (B) and focal subarachnoid hemorrhages (superficial siderosis) (C) on gradient echo T2*-weighted MRI. Posterior distribution of white matter hyperintensities (arrows on T2-weighted MRI) (D).
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Figure 4: Imaging findings of CAA-related hemorrhages and white matter lesions. Fresh (arrow) and old (arrowhead) lobar macrohemorrhages in the frontal lobes on CT (A). Cortical microhemorrhages with lobar distribution (B) and focal subarachnoid hemorrhages (superficial siderosis) (C) on gradient echo T2*-weighted MRI. Posterior distribution of white matter hyperintensities (arrows on T2-weighted MRI) (D).

Mentions: CAA is significantly associated with lobar intracerebral hemorrhage (ICH) (Figure 4A), but not with deep ICH,19 because sporadic Aβ-type CAA is commonly found in the meningeal and cortical vessels of cerebral and cerebellar cortices, and rarely in those of the deep gray matter including basal ganglia, thalamus, and brainstem.6 Using the SMASH-U system (structural lesion, medication, amyloid angiopathy, systemic/other disease, hypertension, undetermined) as a pathogenetic classification system for ICH, CAA-related ICH was noted in 20% of ICH cases in the Helsinki ICH study,20 and 12% of ICH cases in the National Taiwan University Hospital Stroke Registry.21 CAA-related ICH was the second most common cause of ICH following hypertensive angiopathy in these studies.20,21 The incidence of lobar ICH in the elderly has been increasing recently, in which CAA is strongly implicated.22 CAA-related lobar ICH is often multiple and recurrent, and clinical manifestations include motor paresis, disturbance of consciousness, abnormalities in higher brain functions, such as aphasia, visual loss, with headache at the acute stage, and dementia and seizures during chronic stages.9 Headache with meningeal signs is likely caused by subarachnoid hemorrhage (SAH) accompanying lobar ICH.23,24,25


Cerebral amyloid angiopathy: emerging concepts.

Yamada M - J Stroke (2015)

Imaging findings of CAA-related hemorrhages and white matter lesions. Fresh (arrow) and old (arrowhead) lobar macrohemorrhages in the frontal lobes on CT (A). Cortical microhemorrhages with lobar distribution (B) and focal subarachnoid hemorrhages (superficial siderosis) (C) on gradient echo T2*-weighted MRI. Posterior distribution of white matter hyperintensities (arrows on T2-weighted MRI) (D).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4325636&req=5

Figure 4: Imaging findings of CAA-related hemorrhages and white matter lesions. Fresh (arrow) and old (arrowhead) lobar macrohemorrhages in the frontal lobes on CT (A). Cortical microhemorrhages with lobar distribution (B) and focal subarachnoid hemorrhages (superficial siderosis) (C) on gradient echo T2*-weighted MRI. Posterior distribution of white matter hyperintensities (arrows on T2-weighted MRI) (D).
Mentions: CAA is significantly associated with lobar intracerebral hemorrhage (ICH) (Figure 4A), but not with deep ICH,19 because sporadic Aβ-type CAA is commonly found in the meningeal and cortical vessels of cerebral and cerebellar cortices, and rarely in those of the deep gray matter including basal ganglia, thalamus, and brainstem.6 Using the SMASH-U system (structural lesion, medication, amyloid angiopathy, systemic/other disease, hypertension, undetermined) as a pathogenetic classification system for ICH, CAA-related ICH was noted in 20% of ICH cases in the Helsinki ICH study,20 and 12% of ICH cases in the National Taiwan University Hospital Stroke Registry.21 CAA-related ICH was the second most common cause of ICH following hypertensive angiopathy in these studies.20,21 The incidence of lobar ICH in the elderly has been increasing recently, in which CAA is strongly implicated.22 CAA-related lobar ICH is often multiple and recurrent, and clinical manifestations include motor paresis, disturbance of consciousness, abnormalities in higher brain functions, such as aphasia, visual loss, with headache at the acute stage, and dementia and seizures during chronic stages.9 Headache with meningeal signs is likely caused by subarachnoid hemorrhage (SAH) accompanying lobar ICH.23,24,25

Bottom Line: Cerebrovascular Aβ deposits accompany functional and pathological changes in cerebral blood vessels (CAA-associated vasculopathies).Moreover, cSS is closely associated with transient focal neurological episodes (TFNE).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.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurology and Neurobiology of Aging, Kanazawa University Graduate School of Medical Sciences, Kanazawa, Japan.

ABSTRACT
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.

No MeSH data available.


Related in: MedlinePlus