Posture-Dependent Human 3He Lung Imaging in an Open Access MRI System: Initial Results

TL;DR

This study demonstrates the feasibility of using an open-access MRI system to image human lungs in different postures, revealing posture-dependent variations in lung function with hyperpolarized 3He gas.

Contribution

It introduces an open MRI system capable of imaging lungs in vertical and horizontal positions, enabling posture-dependent lung studies previously limited by traditional MRI constraints.

Findings

Posture influences lung imaging results.

Open MRI allows vertical and horizontal lung imaging.

Initial images show detectable differences due to posture.

Abstract

The human lung and its functions are extremely sensitive to orientation and posture, and debate continues as to the role of gravity and the surrounding anatomy in determining lung function and heterogeneity of perfusion and ventilation. However, study of these effects is difficult. The conventional high-field magnets used for most hyperpolarized 3He MRI of the human lung, and most other common radiological imaging modalities including PET and CT, restrict subjects to lying horizontally, minimizing most gravitational effects. In this paper, we briefly review the motivation for posture-dependent studies of human lung function, and present initial imaging results of human lungs in the supine and vertical body orientations using inhaled hyperpolarized 3He gas and an open-access MRI instrument. The open geometry of this MRI system features a "walk-in" capability that permits subjects to be imaged in vertical and horizontal positions, and potentially allows for complete rotation of the orientation of the imaging subject in a two-dimensional plane. Initial results include two-dimensional lung images acquired with ~ 4 mm in-plane resolution and three-dimensional images with ~ 1.5 cm slice thickness. Effects of posture variation are observed.