3D volume-localized pO2 measurement in the human lung with 3He MRI

✍ Scribed by Jim M. Wild; Stan Fichele; Neil Woodhouse; Martyn N.J. Paley; Larry Kasuboski; Edwin J.R. van Beek

• Publisher: John Wiley and Sons
• Year: 2005
• Tongue: English
• Weight: 543 KB
• Volume: 53
• Category: Article
• ISSN: 0740-3194
• DOI: 10.1002/mrm.20423

✦ Synopsis

Abstract

A method for 3D volume‐localized quantification of __p__O2 in the lungs is presented that uses repetitive frame 3D gradient‐echo imaging of ^3^He. The method was demonstrated by experiments on ^3^He phantoms containing known concentrations of O~2~ and in vivo on a group of three healthy human volunteers. The results were compared with those obtained by equivalent 2D thin‐slice and 2D projection methodologies, and were found to be consistent with published results from the 2D projection methodologies (__p__O~2~ = 0.09–0.18 bar). Studies performed on the same subject, on three separate occasions, demonstrated a repeatability of __p__O~2~ measurement to within 14% using the 3D technique. Experimental differences between the 2D and 3D methods were substantiated with theoretical and numerical analyses of the signal decay, which took into account the effects of out‐of‐slice diffusion as a source of error in the thin‐slice 2D experiments. It is shown that the 2D thin‐slice technique systematically underestimates __p__O2 when there is significant gas diffusion (factor of 4 underestimate for D = 0.9 cm^2^s^−1^ representative of free ^3^He in air). Magn Reson Med 53:1055–1064, 2005. © 2005 Wiley‐Liss, Inc.