6533b7d3fe1ef96bd12609e8

RESEARCH PRODUCT

19F-MRT der Lungenventilation in Atemanhaltetechnik mittels SF6-Gas

subject

description

Breathhold 19 F-Magnetic Resonance Imaging of Lung Ventilation using SF 6 Gas. Objective: Development of a method to analyze lung ventilation by 19 F-magnetic resonance imaging (MRI) of inspired SF 6 gas during breathhold. Material and Methods: Measurements were performed with a Siemens Magnetom Vision 1.5T scanner using the conventional gradient overdrive. Coronal images of the lung were acquired using ultrafast gradient-echo pulse sequences with TR/TE/α = 1.4 ms/ 0.48 ms/40° without slice selection. With NEX = 200 averages and MA = 32 × 64 raw data matrix, the acquisition time was 9s/image. Higher spatial resolution of 4.7 × 6.3 × 15 mm 3 was obtained with a three-dimensional pulse sequence (TR/TE/ α = 1.6 ms/0.48 ms/65°, NEX = 20) running for 49 s. Measurements wer performed in three anesthetized and ventilated pigs (18 kg). Results: A nearly linear relation between SF 6 concentration and 19 F signal intensity was observed. The signal-to-noise ratio in images obtained without slice selection was 30.9, with slice selection it was 14.9. No differences between SF 6 distribution to both lungs were observed in the animals. Conclusion: Breathhold MRI of SF 6 gas distribution in the lung was demonstrated for the first time. The low spin-density was compensated for by highly repetitive signal averaging. Breathhold 19 F-MR imaging of ventilated airspaces to assess SF 6 distribution in the human lung appears to be an interesting new method, which can be implemented with little technical efforts, and does not rely on radioactive isotopes.