title: Spectrally selective imaging with wideband balanced steady-state free precession MRI.
abstract: OBJECTIVE
  Unwanted, bright fat signals in balanced steady-state free precession sequences are commonly suppressed using spectral shaping. Here, a new spectral-shaping method is proposed to significantly improve the uniformity of stopband suppression without compromising the level of passband signals.
  
  
  METHODS
  The proposed method combines binomial-pattern excitation pulses with a wideband balanced steady-state free precession sequence kernel. It thereby increases the frequency separation between the centers of pass and stopbands by π radians, enabling improved water-fat contrast. Simulations were performed to find the optimal flip angles and subpulse spacing for the binomial pulses that maximize contrast and signal efficiency.
  
  
  RESULTS
  Comparisons with a conventional binomial balanced steady-state free precession sequence were performed in simulations as well as phantom and in vivo experiments at 1.5 T and 3 T. Enhanced fat suppression is demonstrated in vivo with an average improvement of 58% in blood-fat and 68% in muscle-fat contrast (P < 0.001, Wilcoxon signed-rank test).
  
  
  CONCLUSIONS
  The proposed binomial wideband balanced steady-state free precession method is a promising candidate for spectrally selective imaging with enhanced reliability against field inhomogeneities.
authors.affiliation: Department of Electrical and Electronics Engineering, Bilkent University, Ankara, Turkey.|National Magnetic Resonance Research Center, Bilkent University, Ankara, Turkey.
authors.forename: Tolga
authors.initials: T
authors.lastname: Çukur
mesh_terms: D005223:Fats / Q000737:chemistry; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D007866:Leg / Q000502:physiology; D008279:Magnetic Resonance Imaging / Q000379:methods*; D018482:Muscle, Skeletal / Q000737:chemistry; D019047:Phantoms, Imaging; D014867:Water / Q000737:chemistry
chemical_list: D005223:Fats; D014867:Water
keywords: RF pulse; excitation; fat suppression; selectivity; spectral; steady-state free precession; wideband