Chengbo Wang1, Sylvia Verbanck2, John P. Mugler, III1,3, Kai Ruppert1, Eduard E. de Lange1, F W. Hersman4,5, Isabel M. Dregely4, Iulian Runset4, Stephen Ketel5, Talissa A. Altes1
1Radiology, University of Virginia, Charlottesville, VA, USA; 2Respiratory Division, Academic Hospital UZ Brussel, Brussels, Belgium; 3Biomedical Engineering, University of Virginia, Charlottesville, VA, USA; 4Physics, University of New Hampshire, Durham, NH, USA; 5Xemed LLC, Durham, NH, USA
Long-time-scale 3He and 129Xe diffusion was measured in human lungs and found to depend strongly on diffusion time. The ADC values for both gases were one order of magnitude less than the corresponding short-time-scale ADC values. After normalization by the respective free-diffusion coefficients, 3He and 129Xe diffusion and their dependence on time were similar, suggesting that long-time-scale 3He and 129Xe diffusion probe similar structures. Computer simulations based on an acinar model closely matched the experimental measurements, suggesting that noble gas diffusion is in large part representative of the complex intra-acinar pathways in the lung periphery.