Die Ablagerung von β-Amyloid im Zentralnervensystem ist die Ursache ganz verschiedener
Krankheitsbilder. Trotz identischer Pathophysiologie unterscheiden sie sich markant
hinsichtlich Klinik und bildgebenden Befunden. Dieser Artikel schildert die wichtigsten
klinischen und bildgebenden Merkmale amyloidassoziierter Krankheiten, um dem Radiologen
die für die korrekte Diagnose erforderlichen Kenntnisse an die Hand zu geben.
Abstract
Amyloid-b (Ab) is ubiquitous in the central nervous system (CNS), but pathologic accumulation
of Ab results in four distinct neurologic disorders that affect middle-aged and elderly
adults, with diverse clinical presentations ranging from chronic debilitating dementia
to acute life-threatening intracranial hemorrhage. The characteristic imaging patterns
of Ab-related CNS diseases reflect the pathophysiology of Ab deposition in the CNS. Ab
is recognized as a key component in the neuronal damage that characterizes the pathophysiology
of Alzheimer disease, the most common form of dementia. Targeted molecular imaging
shows pathologic accumulation of Ab and tau protein, and fluorine 18 fluorodeoxyglucose
positron emission tomography and anatomic imaging allow differentiation of typical
patterns of neuronal dysfunction and loss in patients with Alzheimer disease from
those seen in patients with other types of dementia. Cerebral amyloid angiopathy (CAA)
is an important cause of cognitive impairment and spontaneous intracerebral hemorrhage
in the elderly. Hemorrhage and white matter injury seen at imaging reflect vascular
damage caused by the accumulation of Ab in vessel walls. The rare forms of inflammatory
angiopathy attributed to Ab, Ab-related angiitis and CAA-related inflammation, cause
debilitating neurologic symptoms that improve with corticosteroid therapy. Imaging
shows marked subcortical and cortical inflammation due to perivascular inflammation,
which is incited by vascular Ab accumulation. In the rarest of the four disorders,
cerebral amyloidoma, the macroscopic accumulation of Ab mimics the imaging appearance
of tumors. Knowledge of the imaging patterns and pathophysiology is essential for
accurate diagnosis of Ab-related diseases of the CNS.
Schlüsselwörter
Pathologische β-Amyloidablagerung - bildgebende Merkmale - Alzheimer-Krankheit - zerebrale
Amyloidangiopathie
Keywords
pathologic accumulation of Amyloid-b - imaging patterns - Alzheimer disease - cerebral
amyloid angiopathy
