Alzheimer's Disease Research Today is a free monthly online journal that collates and summarizes the latest research about Alzheimer's Disease, including details on diagnosis, memory loss, heredity, treatment, medication.

In vivo visualization of Alzheimer's amyloid plaques by magnetic resonance imaging in transgenic mice without a contrast agent.

Jack CR, Garwood M, Wengenack TM, Borowski B, Curran GL, Lin J, Adriany G, Gröhn OH, Grimm R, Poduslo JF

Department of Radiology, Mayo Clinic College of Medicine, Rochester, Minnesota 55905, USA. jack.clifford@mayo.edu

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.

Published 7 December 2004 in Magn Reson Med, 52(6): 1263-71.
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