Cumulant expansions for measuring water exchange using diffusion MRI

Research output: Contribution to journalArticle

Abstract

The rate of water exchange across cell membranes is a parameter of biological interest and can be measured by diffusion magnetic resonance imaging (dMRI). In this work, we investigate a stochastic model for the diffusion-and-exchange of water molecules. This model provides a general solution for the temporal evolution of dMRI signal using any type of gradient waveform, thereby generalizing the signal expressions for the Kärger model. Moreover, we also derive a general nth order cumulant expansion of the dMRI signal accounting for water exchange, which has not been explored in earlier studies. Based on this analytical expression, we compute the cumulant expansion for dMRI signals for the special case of single diffusion encoding (SDE) and double diffusion encoding (DDE) sequences. Our results provide a theoretical guideline on optimizing experimental parameters for SDE and DDE sequences, respectively. Moreover, we show that DDE signals are more sensitive to water exchange at short-time scale but provide less attenuation at long-time scale than SDE signals. Our theoretical analysis is also validated using Monte Carlo simulations on synthetic structures.

Details

Authors
Organisations
External organisations
  • Brigham and Women's Hospital / Harvard Medical School
  • CR Development AB
  • Harvard University
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Physical Chemistry
  • Radiology, Nuclear Medicine and Medical Imaging
Original languageEnglish
Article number074109
JournalJournal of Chemical Physics
Volume148
Issue number7
Publication statusPublished - 2018 Feb 21
Publication categoryResearch
Peer-reviewedYes