title: MR microscopy of human amyloid-β deposits: characterization of parenchymal amyloid, diffuse plaques, and vascular amyloid.
abstract: Cerebral deposits of amyloid-β peptides (Aβ) form the neuropathological hallmarks of Alzheimer's disease (AD) and cerebral amyloid angiopathy (CAA). In the brain, Aβ can aggregate as insoluble fibrils present in amyloid plaques and vascular amyloid, or as diffuse plaques consisting of mainly non-fibrillar Aβ. Previously, magnetic resonance imaging (MRI) has been shown to be capable of detecting individual amyloid plaques, not only via the associated iron, but also Aβ itself has been suggested to be responsible for a decrease in the image intensity. In this current study we aim to investigate the MRI properties of the different cerebral Aβ deposits including diffuse plaques and vascular amyloid. Postmortem 60-μm-thick brain sections of AD, CAA, and Down's syndrome patients, known to contain Aβ, were studied. High resolution T2*- and T2-weighted MRI scans and quantitative relaxation maps were acquired using a microcoil on a Bruker 9.4T MRI system. Specific MRI characteristics of each type of Aβ deposit were examined by co-registration of the MRI with Congo Red and Aβ-immunostainings of the same sections. Our results show that only fibrillar Aβ, present in both vascular and parenchymal amyloid, induced a significant change in T2* and T2 values. However, signal changes were not as consistent for all of the vessels affected by CAA, irrespective of possible dyshoric changes. In contrast, the non-fibrillar diffuse plaques did not create any detectable MRI signal changes. These findings are relevant for the interpretation and further development of (quantitative) MRI methods for the detection and follow-up of AD and CAA.
authors: Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands. R.J.A.Nabuurs@LUMC.nl
authors: Rob J A
authors: RJ
authors: Nabuurs
authors: Remco
authors: R
authors: Natté
authors: Fenna M
authors: FM
authors: de Ronde
authors: Ingrid
authors: I
authors: Hegeman-Kleinn
authors: Jouke
authors: J
authors: Dijkstra
authors: Sjoerd G
authors: SG
authors: van Duinen
authors: Andrew G
authors: AG
authors: Webb
authors: Annemieke J
authors: AJ
authors: Rozemuller
authors: Mark A
authors: MA
authors: van Buchem
authors: Louise
authors: L
authors: van der Weerd
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000473:pathology* / Q000503:physiopathology*; D016229:Amyloid beta-Peptides / Q000378:metabolism*; D001921:Brain / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology; D016657:Cerebral Amyloid Angiopathy; D003224:Congo Red; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D055806:Microvessels / Q000378:metabolism / Q000473:pathology; D008875:Middle Aged; D010446:Peptide Fragments; D058225:Plaque, Amyloid / Q000473:pathology; D011859:Radiography; D055815:Young Adult
chemical_list: D016229:Amyloid beta-Peptides; D010446:Peptide Fragments; D003224:Congo Red