About the origins of enhanced visualization of amyloid plaques on APP/PS1 mouse brain using GdDOTA passive staining

Introduction T1-relaxating contrast agent (e.g. GdDOTA) “passive staining” is a smart strategy to enhance signal-to-noise ratio (SNR) for MRI microscopy (μMRI) of ex vivo tissue samples. The principle of the method is to immerse organs (e.g. brains) in a solution of GdDOTA and let it diffuse for days in order to reduce the T1 and further reduce the optimum relaxation time (TR) and accordingly the acquisition time. Such strategy has been adopted successfully to detect amyloid plaques in high-resolution T2 -weighted images of APP/PS1 transgenic mice brain [1]. Nevertheless, mechanisms of this contrast enhancement of amyloid plaques were not thoughtfully investigated. In the present study, we have carried such investigation and established how GdDOTA is diffusing throuh tissues during passive staining and what the consequences are for the contrast of amyloid plaques vs. healthy brain tissue.