English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Zendy Plus

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Zendy Tools

Zendy Open

Double diffusion encoding (DDE) makes diffusion MRI sensitive to a wide rangeof microstructural features, and the acquired data can be analysed usingdifferent approaches. Correlation tensor imaging (CTI) uses DDE to resolvethree components of the diffusional kurtosis: isotropic, anisotropic, andmicroscopic. The microscopic kurtosis is estimated from the contrast betweensingle diffusion encoding (SDE) and parallel DDE signals at the same b-value.Another approach is multi-Gaussian exchange (MGE), which employs DDE to measureexchange. Sensitivity to exchange is obtained by contrasting SDE and DDEsignals at the same b-value. CTI and MGE exploit the same signal contrast toquantify microscopic kurtosis and exchange, and this study investigates theinterplay between these two quantities. We perform Monte-Carlo simulations indifferent geometries with varying levels of exchange and study the behaviour ofthe parameters from CTI and MGE. We conclude that microscopic kurtosis from CTIis sensitive to the exchange rate and that intercompartmental exchange and theintrinsic kurtosis of individual compartments are distinct sources ofmicroscopic kurtosis. In an attempt to disentangle these two sources, wepropose a heuristic signal representation referred to as $\mu$MGE (MGEincorporating intrinsic kurtosis) that accounts for both effects, by exploitingthe distinct signatures of exchange and intrinsic kurtosis with varying mixingtime: exchange causes a slow dependence of the signal on mixing time whileintrinsic kurtosis arguably has a much faster dependence. We find that applying$\mu$MGE to data acquired with multiple mixing times for both parallel andorthogonal DDE may allow estimation of the exchange rate as well as theisotropic, anisotropic, and intrinsic kurtosis.

Diffusion MRI with double diffusion encoding and variable mixing times disentangles water exchange from intrinsic kurtosis