title: Comparison of self-gated cine MRI retrospective cardiac synchronization algorithms.
abstract: OBJECTIVE
  To determine whether improved self-gating (SG) algorithms can provide superior synchronization accuracy for retrospectively gated cine MRI.
  
  
  METHODS
  First difference, template matching, and polynomial fitting algorithms were implemented to improve the synchronization of MRI data using cardiac SG signals. Cine datasets were acquired during short-axis, two-, three-, and four-chamber cardiac MRI scans. The root-mean-square (RMS) error of SG synchronization positions compared to detected R-wave positions were calculated along with the mean square error (MSE) and peak signal-to-noise ratio (PSNR) comparing SG to electrocardiogram (ECG)-gated images. Overall image quality was also compared by two expert reviewers.
  
  
  RESULTS
  RMS errors were highest for the first difference method for all orientations. Improvements for both template matching and cubic polynomial fitting methods were significant for two-, three-, and four-chamber scans. MSE values were lower and PSNR were significantly higher for the cubic method compared to the first difference method for all orientations. Reviewers scored the images to be of comparable quality.
  
  
  CONCLUSIONS
  Template matching and polynomial fitting improved the accuracy of cardiac cycle synchronization for two-, three-, and four-chamber scans; improvements in SG synchronization accuracy were reflected in improvements in analytical image quality. Implementation of robust postprocessing algorithms may bring SG approaches closer to clinical utilization.
authors.affiliation: Department of Electrical Engineering and Computer Science, Northwestern University, Evanston, Illinois 60208, USA.
authors.forename: Grace M
authors.initials: GM
authors.lastname: Nijm
authors.forename: Alan V
authors.initials: AV
authors.lastname: Sahakian
authors.forename: Steven
authors.initials: S
authors.lastname: Swiryn
authors.forename: James C
authors.initials: JC
authors.lastname: Carr
authors.forename: John J
authors.initials: JJ
authors.lastname: Sheehan
authors.forename: Andrew C
authors.initials: AC
authors.lastname: Larson
mesh_terms: D000328:Adult; D000465:Algorithms; D005260:Female; D006321:Heart / Q000033:anatomy & histology*; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D055425:Respiratory-Gated Imaging Techniques / Q000379:methods*; D012680:Sensitivity and Specificity
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