Regional differences in MRI detection of amyloid plaques in AD transgenic mouse brain

►Human Alzheimer's disease (AD) and AD transgenic mouse amyloid plaques contain iron. ►Many MR studies have attempted to image amyloid plaques using T2*-weighted pulse sequences that maximize the magnetic susceptibility effects of iron. ►APP/PS1 transgenic mice develop two types of amyloid plaques based on histological and morphological analysis: (1) fibrillar, found predominantly in the cerebral cortex and hippocampus, and (2) spherical, found only in the thalamus. ►Fibrillar plaques more closely replicate human AD amyloid plaques, but contain very low levels of iron and are much less detectable by T2*-weighted MR. ►T2-weighted (spin echo) MR relies less on the magnetic susceptibility of iron and can detect fibrillar cortical and hippocampal amyloid plaques better than T2*-weighted MR.