title: Cardiac functional assessment without electrocardiogram using physiological self-navigation.
abstract: OBJECTIVE
  Electrocardiogram (ECG)-gated cine MRI provides highly accurate functional assessment of the heart. Nevertheless, reliable ECG signals are not always available due to patient's electrophysiology or due to high MR field strengths. Here, a novel framework for cardiac functional assessment using physiological information is presented, which is obtained from MR image data.
  
  
  METHODS
  Multiple long-axis slices rotated around the center axis of the left ventricle are acquired using a 2D Golden Radial acquisition scheme. This sampling approach allows for both real-time data and retrospectively reordered cine images with different temporal resolutions. Functional information from the left ventricle is used for retrospective reordering of the data to reconstruct cine images without an external ECG signal. Afterward, individual 2D cine slices are synchronized using physiological information on the mitral valve closure. The proposed approach was assessed in 15 volunteers and applied in four patients for feasibility.
  
  
  RESULTS
  Physiological gating signals obtained with our approach show great correlation with an ECG reference signal. Functional parameters determined with the presented method show a relative difference of less than 1.3% when compared with an ECG-gated approach.
  
  
  CONCLUSIONS
  It is successfully demonstrated that functional assessment of the heart is possible using physiological information obtained directly from MR image data.
authors.affiliation: Division of Imaging Sciences and Biomedical Engineering, King's College London, London, UK.
authors.forename: Christoph
authors.initials: C
authors.lastname: Kolbitsch
authors.forename: Claudia
authors.initials: C
authors.lastname: Prieto
authors.forename: Tobias
authors.initials: T
authors.lastname: Schaeffter
mesh_terms: D000328:Adult; D055424:Cardiac-Gated Imaging Techniques; D003199:Computer Systems; D004562:Electrocardiography; D005240:Feasibility Studies; D005260:Female; D006334:Heart Function Tests / Q000379:methods*; D006352:Heart Ventricles / Q000473:pathology*; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D008297:Male; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013318:Stroke Volume; D018487:Ventricular Dysfunction, Left / Q000473:pathology*