title: Self-gated fat-suppressed cardiac cine MRI.
abstract: OBJECTIVE
  To develop a self-gated alternating repetition time balanced steady-state free precession (ATR-SSFP) pulse sequence for fat-suppressed cardiac cine imaging.
  
  
  METHODS
  Cardiac gating is computed retrospectively using acquired magnetic resonance self-gating data, enabling cine imaging without the need for electrocardiogram (ECG) gating. Modification of the slice-select rephasing gradients of an ATR-SSFP sequence enables the acquisition of a one-dimensional self-gating readout during the unused short repetition time (TR). Self-gating readouts are acquired during every TR of segmented, breath-held cardiac scans. A template-matching algorithm is designed to compute cardiac trigger points from the self-gating signals, and these trigger points are used for retrospective cine reconstruction. The proposed approach is compared with ECG-gated ATR-SSFP and balanced steady-state free precession in 10 volunteers and five patients.
  
  
  RESULTS
  The difference of ECG and self-gating trigger times has a variability of 13 ± 11 ms (mean ± SD). Qualitative reviewer scoring and ranking indicate no statistically significant differences (P > 0.05) between self-gated and ECG-gated ATR-SSFP images. Quantitative blood-myocardial border sharpness is not significantly different among self-gated ATR-SSFP ( 0.61±0.15 mm -1), ECG-gated ATR-SSFP ( 0.61±0.15 mm -1), or conventional ECG-gated balanced steady-state free precession cine MRI ( 0.59±0.15 mm -1).
  
  
  CONCLUSIONS
  The proposed self-gated ATR-SSFP sequence enables fat-suppressed cardiac cine imaging at 1.5 T without the need for ECG gating and without decreasing the imaging efficiency of ATR-SSFP.
authors.affiliation: Magnetic Resonance Systems Research Laboratory, Department of Electrical Engineering, Stanford University, Stanford, California, USA.
authors.forename: R Reeve
authors.initials: RR
authors.lastname: Ingle
authors.forename: Juan M
authors.initials: JM
authors.lastname: Santos
authors.forename: William R
authors.initials: WR
authors.lastname: Overall
authors.forename: Michael V
authors.initials: MV
authors.lastname: McConnell
authors.forename: Bob S
authors.initials: BS
authors.lastname: Hu
authors.forename: Dwight G
authors.initials: DG
authors.lastname: Nishimura
mesh_terms: D000465:Algorithms; D055424:Cardiac-Gated Imaging Techniques; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D008297:Male; D008536:Meglumine / Q000031:analogs & derivatives; D009200:Myocardial Contraction / Q000502:physiology; D009942:Organometallic Compounds; D012016:Reference Values; D012680:Sensitivity and Specificity
chemical_list: D009942:Organometallic Compounds; C064572:gadobenic acid; D008536:Meglumine
keywords: alternating repetition time; cardiac imaging; cine magnetic resonance imaging; self gating; steady-state free precession