title: Free-breathing 3D steady-state free precession coronary magnetic resonance angiography: comparison of diaphragm and cardiac fat navigators.
abstract: OBJECTIVE
  To compare the performance of the conventional diaphragm navigator (DNAV) and the recently developed cardiac fat navigator (FatNAV) in suppressing respiration-induced cardiac motion in free-breathing 3D balanced steady-state free precession coronary MRA (SSFP CMRA).
  
  
  METHODS
  In 16 healthy volunteers the right coronary artery (RCA) was imaged at 1.5T using a navigator-gated 3D SSFP CMRA sequence. DNAV and FatNAV gating were performed in random order. Image quality difference was scored by three experienced readers blinded to the gating technique. Blood signal-to-noise ratio (SNR), blood-to-myocardium contrast-to-noise ratio (CNR), and navigator efficiency were calculated.
  
  
  RESULTS
  Diagnostically interpretable CMRA was obtained successfully in all 16 subjects with FatNAV gating (0% failure rate) and only 14 subjects with DNAV gating (12% failure rate). Compared to DNAV gating, FatNAV gating provided similar SNR and CNR, better image quality (P < 0.01), and 28% improvement in navigator efficiency (P = 0.002).
  
  
  CONCLUSIONS
  FatNAV gating provides more effective motion suppression and better image quality than DNAV gating for free-breathing 3D SSFP CMRA of the RCA in healthy subjects.
authors.affiliation: Department of Radiology, Weill Medical College of Cornell University, New York, New York 10022, USA. tdn2001@med.cornell.edu
authors.forename: Thanh D
authors.initials: TD
authors.lastname: Nguyen
authors.forename: Pascal
authors.initials: P
authors.lastname: Spincemaille
authors.forename: Matthew D
authors.initials: MD
authors.lastname: Cham
authors.forename: Jonathan W
authors.initials: JW
authors.lastname: Weinsaft
authors.forename: Martin R
authors.initials: MR
authors.lastname: Prince
authors.forename: Yi
authors.initials: Y
authors.lastname: Wang
mesh_terms: D000273:Adipose Tissue / Q000033:anatomy & histology*; D000328:Adult; D016477:Artifacts; D003331:Coronary Vessels; D003964:Diaphragm / Q000033:anatomy & histology*; D004562:Electrocardiography; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009068:Movement; D012119:Respiration; D018709:Statistics, Nonparametric