Ventilation Study of the Human Lungs by 19 F MRI at 0.5 Tesla

To show the feasibility of functional lung assessment by 19 F MRI using low field (0.5 T) MRI scanner. One healthy volunteer participated in the studies. As a contrast for 19 F pulmonary MRI, the gas mixture of 70% octafluorocyclobutane (OFCB) and 30% oxygen was used. 19 F MR images of human lungs were obtained using 2D and 3D FSE methods. MRI data were used for volume reconstruction and for calculation of wash-in/-out and single-breath dynamics measurements. 19 F 3D imaging provided information about gas distribution and lung volume assessment. The measured volume of the left and right parts of lungs were ≈1.7L and ≈1.8L, respectively. The wash-in/-out dynamics measurements determined that the effective time of gas washing in was 30 ± 5 s and washing out was 19 ± 4 s. Fractional ventilation was 29 ± 3% and 18 ± 2% for wash-in and wash-out processes, respectively. Dynamics of gas distribution during one breath cycle was analyzed. The calculated inspiration and expiration maps gave normalized effective times [rel. un.] for these stages- 0.95 ± 0.18 and 0.84 ± 0.15, respectively. Different 19 F pulmonary MRI methods were implemented: 3D imaging, wash-in/-out dynamics and single respiratory cycle imaging. The results are agreed with known data and demonstrates possibility of ventilation assessment of the lungs at 0.5 Tesla.