Dynamic F-19-MRI of pulmonary ventilation using sulfur hexafluoride (SF6) gas

A new method for dynamic imaging of pulmonary wash-in and wash-out kinetics of inhaled sulfur hexafluoride (SF,) gas was developed. Measurements at th e fluorine-19 Larmor frequency were performed in pigs using a gradient echo pulse sequence with 0.5 ms echo time and a measurement time of 9.1 s per i mage, Dynamic MRI was performed during wash-in and washout of SF6 gas in me chanically ventilated porcine lungs, A postprocessing strategy was develope d for quantitative determination of wash-out time constants in the presence of noise. Mean wash-out constants were 4.78 +/- 0.48 breaths vs, 4.33 +/- 0.76 breaths for left and right lung when ventilation was performed with lo w tidal volume, and 1.73 +/- 0.16 breaths vs. 1.85 +/- 0.11 breaths with hi gh tidal volume ventilation, In conclusion, breath-hold MRI of SF6 gas is f easible in large animals. Moreover, regional wash-in and wash-out kinetics of SF6 can be determined noninvasively with this new method, Potential huma n applications are discussed. Magn Reson Med 45: 605-613, 2001. (C) 2001 Wi ley-Liss, Inc.