Diffusion corrected reconstructions of partial pressure of oxygen using polarized gas MRI
Yu J, Ishii M, Kadlecek S, MacDuffie Woodburn J, Emami K, Rajaei S, Hammond F, Vahdat V, Rizi R
University of Pennsylvania
Hyperpolarized (HP) 3He MRI measures of regional oxygen tensions provide important insight into lung function under physiologic and pathophysiologic conditions. This stems from the unique correlation between the lungs steady state oxygen tensions and its ventilation perfusion ratios; a similar relationship exists between the lungs the oxygen degradation rate and local alveolar perfusion. Thus these measures are of great interest to pulmonologists and physiologists. Current HP oxygen measurement techniques assume that diffusion of the HP gas during the measurement cycle affects the measured signal intensity negligibly. We show that under many conditions this assumption is false and severely degrades measurement accuracy; we present the first direct oxygen reconstruction algorithm for measuring regional oxygen tensions in the presence of a diffusing HP contrast agent. Numerical simulations and experimental results are presented as well.