title: Combined outer volume suppression and T2 preparation sequence for coronary angiography.
abstract: OBJECTIVE
  To develop a magnetization preparation sequence for simultaneous outer volume suppression (OVS) and T2 weighting in whole-heart coronary magnetic resonance angiography.
  
  
  METHODS
  A combined OVS and T2 preparation sequence (OVS-T2 Prep) was designed with a nonselective adiabatic 90° tipdown pulse, two adiabatic 180° refocusing pulses, and a 2D spiral -90° tipup pulse. The OVS-T2 Prep preserves the magnetization inside an elliptic cylinder with T2 weighting, while saturating the magnetization outside the cylinder. Its performance was tested on phantoms and on 13 normal subjects with coronary magnetic resonance angiography using 3D cones trajectories.
  
  
  RESULTS
  Phantom studies showed expected T2 -dependent signal amplitude in the spatial passband and suppressed signal in the spatial stopband. In vivo studies with full-field-of-view cones yielded a passband-to-stopband signal ratio of 3.18 ± 0.77 and blood-myocardium contrast-to-noise ratio enhancement by a factor of 1.43 ± 0.20 (P < 0.001). In vivo studies with reduced-field-of-view cones showed that OVS-T2 Prep well suppressed the aliasing artifacts, as supported by significantly reduced signal in the regions with no tissues compared to the images acquired without preparation (P < 0.0001).
  
  
  CONCLUSIONS
  OVS-T2 Prep is a compact sequence that can accelerate coronary magnetic resonance angiography by suppressing signals from tissues surrounding the heart while simultaneously enhancing the blood-myocardium contrast.
authors.affiliation: Department of Electrical Engineering, Magnetic Resonance Systems Research Laboratory, Stanford University, Stanford, California, USA.
authors.forename: Jieying
authors.initials: J
authors.lastname: Luo
authors.affiliation: Department of Electrical Engineering, Magnetic Resonance Systems Research Laboratory, Stanford University, Stanford, California, USA.
authors.forename: Nii Okai
authors.initials: NO
authors.lastname: Addy
authors.affiliation: Department of Electrical Engineering, Magnetic Resonance Systems Research Laboratory, Stanford University, Stanford, California, USA.
authors.forename: R Reeve
authors.initials: RR
authors.lastname: Ingle
authors.affiliation: Department of Radiology, Stanford University, Stanford, California, USA.
authors.forename: Brian A
authors.initials: BA
authors.lastname: Hargreaves
authors.affiliation: Department of Electrical Engineering, Magnetic Resonance Systems Research Laboratory, Stanford University, Stanford, California, USA.|Palo Alto Medical Foundation, Palo Alto, California, USA.
authors.forename: Bob S
authors.initials: BS
authors.lastname: Hu
authors.affiliation: Department of Electrical Engineering, Magnetic Resonance Systems Research Laboratory, Stanford University, Stanford, California, USA.
authors.forename: Dwight G
authors.initials: DG
authors.lastname: Nishimura
authors.affiliation: Diagnostic Radiology and Nuclear Medicine, University of Maryland, Baltimore, Maryland, USA.
authors.forename: Taehoon
authors.initials: T
authors.lastname: Shin
mesh_terms: D000328:Adult; D016477:Artifacts; D017023:Coronary Angiography / Q000379:methods*; D003331:Coronary Vessels / Q000033:anatomy & histology*; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted
keywords: T2 Prep; cones imaging; coronary MR angiography; outer volume suppression; radiofrequency pulse design