Rapid 3D lung imaging with bSSFP stack of spiral out-in (SoSoi) sampling at 0.55T

MRI provides radiation-free screening of many lung diseases. Its use has been limited at field strengths >1.5T, largely due to the ultra-shot T2* and low proton density in the lung. New 0.55T systems provide improved lung MRI capability since T2* is prolonged to the order of 10ms. In this work, we propose a rapid 3D bSSFP stack-of-spiral out-in (SoSoi) pulse sequence for lung imaging. The sequence can acquire 2 mm isotropic resolution image with 23 sec breathhold or 2.4 mm isotropic resolution image with 13 sec breathhold, both show great pulmonary vessels depiction.