Ultra-fast Steady-State Free Precession Pulse Sequence for Fourier Decomposition Pulmonary MRI

To assess whether ultra-fast steady-state free precession (ufSSFP) can improve image quality in Fourier decomposition (FD) MRI of lung ventilation and perfusion.

Series of two-dimensional time-resolved lung images were acquired in healthy volunteers at 1.5 Tesla (T) and 3T using an FD adapted ufSSFP. For comparison, the imaging protocol was complemented by a standard implementation of the FD MRI technique using balanced steady-state free precession (bSSFP). Imaging parameters were evaluated to optimize the ufSSFP FD MRI protocol with respect to the signal intensity of the lung parenchyma and the severity of image artifacts.

FD MRI with the adapted ufSSFP pulse sequence resulted in increased signal intensity in the lung tissue by 19% and significantly decreased banding artifacts due to shorter repetition times: 1.46 ms for ufSSFP and 1.90 ms for bSSFP. Despite improved image quality FD MRI is still problematic at 3T.

MRI of the lung with ufSSFP performs better than bSSFP in terms of signal and banding artifacts, and can be used to either increase resolution or overall image quality of FD images.