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

PurposeTo obtain whole lung morphometry measurements from Xe-129 in a single breath-hold with 3D multiple b-value Xe-129 diffusion-weighted MRI (DW-MRI) with an empirically optimized diffusion time and compressed sensing for scan acceleration. MethodsProspective three-fold undersampled 3D multiple b-value hyperpolarized Xe-129 DW-MRI datasets were acquired, and the diffusion time () was iterated so as to provide diffusive length scale (Lm(D)) estimates from the stretched exponential model (SEM) that are comparable to those from He-3. The empirically optimized Xe-129 diffusion time was then implemented with a four-fold undersampling scheme and was prospectively benchmarked against He-3 measurements in a cohort of five healthy volunteers, six ex-smokers, and two chronic obstructive pulmonary disease patients using both SEM-derived Lm(D) and cylinder model (CM)-derived mean chord length (Lm). ResultsGood agreement between the mean Xe-129 and He-3 Lm(D) (mean difference, 2.2%) and Lm (mean difference, 1.1%) values was obtained in all subjects at an empirically optimized Xe-129 =8.5 ms. ConclusionCompressed sensing has facilitated single-breath 3D multiple b-value Xe-129 DW-MRI acquisitions, and results at Xe-129 =8.5 ms indicate that Xe-129 provides a viable alternative to He-3 for whole lung morphometry mapping with either the SEM or CM. Magn Reson Med 79:2986-2995, 2018. (c) 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.