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

To show the feasibility of functional lung assessment by 19F MRI using low field (0.5 T) MRI scanner. One healthy volunteer participated in the studies. As a contrast for 19F pulmonary MRI, the gas mixture of 70% octafluorocyclobutane (OFCB) and 30% oxygen was used. 19F 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. 19F 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 19F 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.