Examining lung microstructure using 19F MR diffusion imaging in COPD patients
Arnd Jonathan Obert, Marcel Gutberlet, Agilo Luitger Kern, Till Frederik Kaireit, Julian Glandorf, Tawfik Moher Alsady, Frank Wacker, Jens Michael Hohlfeld, Jens Vogel-Claussen
Abstract
Purpose
To examine the time-dependent diffusion of fluorinated (19F) gas in human lungs for determination of surface-to-volume ratio in comparison to results from hyperpolarized 129Xe and lung function testing in healthy volunteers and patients with chronic obstructive pulmonary disease.
Methods
Diffusion of fluorinated gas in the short-time regime was measured using multiple gradient-echo sequences with a single pair of trapezoidal gradient pulses. Pulmonary surface-to-volume ratio was calculated using a first-order approximation of the time-dependent diffusion in a study with 20 healthy volunteers and 22 patients with chronic obstructive pulmonary disease. The repeatability after 7 days as well as the correlation with hyperpolarized 129Xe diffusion MRI and lung function testing was analyzed.
Results
Using 19F diffusion MRI, the median surface-to-volume ratio is significantly decreased in chronic obstructive pulmonary disease patients (S/V = 126 cm−1 [87–144 cm−1]) compared with healthy volunteers (S/V = 164 cm−1 [160–84 cm−1], p < 0.0001). No significant difference was found between measurements within 7 days for healthy (p = 0.88, median coefficient of variation = 4.3%) and diseased subjects (p = 0.58, median coefficient of variation= 6.7%). Linear correlations were found with S/V from 129Xe diffusion MRI (r = 0.85, p = 0.001) and the forced expiratory volume in 1 second (r = 0.68, p < 0.0001).
Conclusion
Examination of lung microstructure using time-dependent diffusion measurement of inhaled 19F is feasible, repeatable, and correlates with established measurements.