Abstract #0881

Regional Ventilation Mapping of the Rat Lung using Hyperpolarized 3He & 129Xe Magnetic Resonance Imaging

Marcus John Couch^1,2, Alexei V. Ouriadov¹, Giles E. Santyr^1,3

¹Imaging Research Laboratories, Robarts Research Institute, The University of Western Ontario, London, ON, Canada; ²Department of Physics & Astronomy, the University of Western Ontario, London, ON, Canada; ³Department of Medical Biophysics, The University of Western Ontario, London, ON, Canada

In this work, hyperpolarized ³He and ¹²⁹Xe MRI was used to measure regional ventilation in the normal rat lung using the dynamic gas signal from inside the lungs. This method used a variable flip angle approach (FAVOR) to mitigate the effects of RF pulses and relaxation both in the ventilator system and in the rat lung. A theoretical model was used to fit signal enhancement curves on a pixel-by-pixel basis to generate two-dimensional maps of the ventilation parameter, r, which was defined as the fractional refreshment of gas per breath. Ventilation gradients were calculated in the superior/inferior and anterior/posterior directions.