3D diffusion-weighted (129) Xe MRI for whole lung morphometry

PURPOSE:

To obtain whole lung morphometry measurements from (129) Xe in a single breath-hold with 3D multiple b-value (129) Xe diffusion-weighted MRI (DW-MRI) with an empirically optimized diffusion time and compressed sensing for scan acceleration.

METHODS:

Prospective three-fold undersampled 3D multiple b-value hyperpolarized (129) Xe DW-MRI datasets were acquired, and the diffusion time (Δ) was iterated so as to provide diffusive length scale (LmD ) estimates from the stretched exponential model (SEM) that are comparable to those from (3) He. The empirically optimized (129) Xe diffusion time was then implemented with a four-fold undersampling scheme and was prospectively benchmarked against (3) He measurements in a cohort of five healthy volunteers, six ex-smokers, and two chronic obstructive pulmonary disease patients using both SEM-derived LmD and cylinder model (CM)-derived mean chord length (Lm).

RESULTS:

Good agreement between the mean (129) Xe and (3) He LmD (mean difference, 2.2%) and Lm (mean difference, 1.1%) values was obtained in all subjects at an empirically optimized (129) Xe Δ = 8.5 ms.

CONCLUSION:

Compressed sensing has facilitated single-breath 3D multiple b-value (129) Xe DW-MRI acquisitions, and results at (129) Xe Δ = 8.5 ms indicate that (129) Xe provides a viable alternative to (3) He for whole lung morphometry mapping with either the SEM or CM. Magn Reson Med, 2017. © 2017 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.