title: In vivo visualization of Alzheimer's amyloid plaques by magnetic resonance imaging in transgenic mice without a contrast agent.
abstract: One of the cardinal pathologic features of Alzheimer's disease (AD) is the formation of senile, or amyloid, plaques. Transgenic mice have been developed that express one or more of the genes responsible for familial AD in humans. Doubly transgenic mice develop "human-like" plaques, providing a mechanism to study amyloid plaque biology in a controlled manner. Imaging of labeled plaques has been accomplished with other modalities, but only MRI has sufficient spatial and contrast resolution to visualize individual plaques noninvasively. Methods to optimize visualization of plaques in vivo in transgenic mice at 9.4 T using a spin echo sequence based on adiabatic pulses are described. Preliminary results indicate that a spin echo acquisition more accurately reflects plaque size, while a T2* weighted gradient echo sequence reflects plaque iron content, not plaque size. In vivo MRI-ex vivo MRI-in vitro histologic correlations are provided. Histologically verified plaques as small as 50 microm in diameter were visualized in living animals. To our knowledge this work represents the first demonstration of noninvasive in vivo visualization of individual AD plaques without the use of a contrast agent.
authors.affiliation: Department of Radiology, Mayo Clinic College of Medicine, Rochester, Minnesota 55905, USA. jack.clifford@mayo.edu
authors.forename: Clifford R
authors.initials: CR
authors.lastname: Jack
authors.forename: Michael
authors.initials: M
authors.lastname: Garwood
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Wengenack
authors.forename: Bret
authors.initials: B
authors.lastname: Borowski
authors.forename: Geoffrey L
authors.initials: GL
authors.lastname: Curran
authors.forename: Joseph
authors.initials: J
authors.lastname: Lin
authors.forename: Gregor
authors.initials: G
authors.lastname: Adriany
authors.forename: Olli H J
authors.initials: OH
authors.lastname: Gröhn
authors.forename: Roger
authors.initials: R
authors.lastname: Grimm
authors.forename: Joseph F
authors.initials: JF
authors.lastname: Poduslo
mesh_terms: D000544:Alzheimer Disease / Q000473:pathology*; D000818:Animals; D001921:Brain / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D051379:Mice; D008822:Mice, Transgenic; D058225:Plaque, Amyloid / Q000473:pathology*