Rapid detection of the presence of diffusion exchange

Teddy X Cai; Dan Benjamini; Michal E Komlosh; Peter J Basser; Nathan H Williamson

doi:10.1016/j.jmr.2018.10.004

Rapid detection of the presence of diffusion exchange

J Magn Reson. 2018 Dec:297:17-22. doi: 10.1016/j.jmr.2018.10.004. Epub 2018 Oct 10.

Authors

Teddy X Cai¹, Dan Benjamini², Michal E Komlosh³, Peter J Basser², Nathan H Williamson⁴

Affiliations

¹ Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, PA, USA; National Institute of Biomedical Imaging and Bioengineering (BESIP), National Institutes of Health, Bethesda, MD, USA.
² Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA.
³ Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA; The Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, MD, USA.
⁴ Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA. Electronic address: nathan.williamson@nih.gov.

Abstract

Diffusion exchange spectroscopy (DEXSY) provides a detailed picture of how fluids in different microenvironments communicate with one another but requires a large amount of data. For DEXSY MRI, a simple measure of apparent exchanging fractions may suffice to characterize and differentiate materials and tissues. Reparameterizing signal intensity from a PGSE-storage-PGSE experiment as a function of the sum, b_s=b₁+b₂, and difference b_d=b₂-b₁ of the diffusion encodings separates diffusion weighting from exchange weighting. Exchange leads to upward curvature along a slice of constant b_s. Exchanging fractions can be measured rapidly by a finite difference approximation of the curvature using four data points. The method is generalized for non-steady-state and multi-site exchange. We apply the method to image exchanging fractions and calculate exchange rates of water diffusing across the bulk water interface of a glass capillary array.

Keywords: Apparent exchange rate; Exchange-weighted imaging; Inverse Laplace; Permeability; Porous media; Pulsed gradient spin echo NMR; Time-domain analysis; Transcytolemmal water exchange.

Published by Elsevier Inc.

Publication types

Research Support, Non-U.S. Gov't

Abstract

Publication types

Grants and funding