Abstract #2213

Experimental Measurements and Computer Simulation of Long-Time-Scale Hyperpolarized 3He and 129Xe Diffusion in Human Lungs

Chengbo Wang¹, Sylvia Verbanck², John P. Mugler, III^1,3, Kai Ruppert¹, Eduard E. de Lange¹, F W. Hersman^4,5, 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.