Diffusion kurtosis imaging to detect amyloidosis in an APP/PS1 mouse model for Alzheimer's disease

Amyloid deposition in the brain is considered an initial event in the progression of Alzheimer's disease. We hypothesized that the presence of amyloid plaques in the brain of APP/presenilin 1 mice leads to higher diffusion kurtosis measures due to increased microstructural complexity. As such, our purpose was to provide an in vivo proof of principle for detection of amyloidosis by diffusion kurtosis imaging (DKI).

APPKM670/671NL /presenilin 1 L166P mice (n = 5) and wild-type littermates (n = 5) underwent DKI at the age of 16 months. Averaged diffusion and diffusion kurtosis parameters were obtained for multiple regions (hippocampus-cortex-thalamus-cerebellum). After DKI, mice were sacrificed for amyloid staining.

Histograms of the frequency distribution of the DKI parameters tended to shift to higher values. After normalization of absolute values to the cerebellum, a nearly plaque-free region, mean, radial, and axial diffusion kurtosis were significantly higher in APP/presenilin 1 mice as compared to wild-type in the cortex and thalamus, regions demonstrating substantial amyloid staining.

The current study, although small-scale, suggests increased DKI metrics, in the absence of alterations in diffusion tensor imaging metrics in the cortex and thalamus of APP/presenilin 1 mice with established amyloidosis. These results warrant further investigations on the potential of DKI as a sensitive marker for Alzheimer's disease.