Fluid-attenuated inversion-recovery SSFP imaging.
OBJECTIVE
To describe and evaluate a fast, fluid-suppressed 2D multislice steady-state free precession (SSFP) neuroimaging sequence.


METHODS
We developed a fast fluid-attenuated inversion-recovery SSFP sequence for use in neuroimaging. The inversion time (TI) was optimized to yield good cerebrospinal fluid (CSF) suppression while conserving white matter (WM)/lesion contrast across a broad range of flip angles. Multiple SSFP acquisitions were combined using the sum-of-squares (SOS) method to maximize SNR efficiency while minimizing SSFP banding artifacts. We compared our fluid-attenuated inversion-recovery (FLAIR) SSFP sequence with FLAIR fast spin-echo (FSE) in both normal subjects and a volunteer with multiple sclerosis. SNR measurements were performed to ascertain the SNR efficiency of each sequence.


RESULTS
Our FLAIR SSFP sequence demonstrated excellent CSF suppression and good gray matter (GM)/WM contrast. Coverage of the entire brain (5-mm slices, 24-cm FOV, 256 x 192 matrix) was achieved with FLAIR SSFP in less than half the scan time of a corresponding FLAIR FSE sequence with similar SNR, yielding improvements of more than 50% in SNR efficiency. Axial scans of a volunteer with multiple sclerosis show clearly visible plaques and very good visualization of brain parenchyma.


CONCLUSIONS
We have demonstrated the feasibility of a very fast fluid-suppressed neuroimaging technique using SSFP.
Bangerter
Neal K
NK
Department of Electrical Engineering, Stanford University, Stanford, California, USA. nealb@mrsrl.stanford.edu
Hargreaves
Brian A
BA
Gold
Garry E
GE
Stucker
Daniel T
DT
Nishimura
Dwight G
DG
D000465:Algorithms; D016477:Artifacts; D001921:Brain / Q000033:anatomy & histology*; D002555:Cerebrospinal Fluid / Q000166:cytology*; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013382:Subtraction Technique