Characterizing Surface-to-Volume Ratio Using Hyperpolarized Xenon-129 Exchange Dynamics in a Rabbit Model
Ruppert K, Mata J, Cai J, Altes T, Mugler III J, Brookeman J, Tobias W, Wang H, Cates Jr G
In this study we investigated whether MR measurements of hyperpolarized Xe-129 inter-phase exchange can characterize the surface-to-volume ratio (S/V) of the lung. Lung emphysema was induced in 5 rabbits to produce S/V changes; 3 rabbits were used as control. Depolarization of the gas-phase signal was measured after ventilation with 50cc hyperpolarized Xe-129. Slopes of the depolarization curves were calculated and compared with S/V from morphology. The emphysema group demonstrated a lower slope (0.7320.106) than the control group (0.9070.0448). Slopes correlated well (r=0.9551) with S/V. The results suggest this technique may be useful to detect changes in S/V of the lung.