title: Comparison of left ventricular function assessment using phonocardiogram- and electrocardiogram-triggered 2D SSFP CINE MR imaging at 1.5 T and 3.0 T.
abstract: OBJECTIVE
  As high-field cardiac MRI (CMR) becomes more widespread the propensity of ECG to interference from electromagnetic fields (EMF) and to magneto-hydrodynamic (MHD) effects increases and with it the motivation for a CMR triggering alternative. This study explores the suitability of acoustic cardiac triggering (ACT) for left ventricular (LV) function assessment in healthy subjects (n = 14).
  
  
  METHODS
  Quantitative analysis of 2D CINE steady-state free precession (SSFP) images was conducted to compare ACT's performance with vector ECG (VCG). Endocardial border sharpness (EBS) was examined paralleled by quantitative LV function assessment.
  
  
  RESULTS
  Unlike VCG, ACT provided signal traces free of interference from EMF or MHD effects. In the case of correct R-wave recognition, VCG-triggered 2D CINE SSFP was immune to cardiac motion effects-even at 3.0 T. However, VCG-triggered 2D SSFP CINE imaging was prone to cardiac motion and EBS degradation if R-wave misregistration occurred. ACT-triggered acquisitions yielded LV parameters (end-diastolic volume (EDV), end-systolic volume (ESV), stroke volume (SV), ejection fraction (EF) and left ventricular mass (LVM)) comparable with those derived from VCG-triggered acquisitions (1.5 T: ESV(VCG) = (56 +/- 17) ml, EDV(VCG) = (151 +/- 32) ml, LVM(VCG) = (97 +/- 27) g, SV(VCG) = (94 +/- 19) ml, EF(VCG) = (63 +/- 5)% cf. ESV(ACT) = (56 +/- 18) ml, EDV(ACT) = (147 +/- 36) ml, LVM(ACT) = (102 +/- 29) g, SV(ACT) = (91 +/- 22) ml, EF(ACT) = (62 +/- 6)%; 3.0 T: ESV(VCG) = (55 +/- 21) ml, EDV(VCG) = (151 +/- 32) ml, LVM(VCG) = (101 +/- 27) g, SV(VCG) = (96 +/- 15) ml, EF(VCG) = (65 +/- 7)% cf. ESV(ACT) = (54 +/- 20) ml, EDV(ACT) = (146 +/- 35) ml, LVM(ACT) = (101 +/- 30) g, SV(ACT) = (92 +/- 17) ml, EF(ACT) = (64 +/- 6)%).
  
  
  CONCLUSIONS
  ACT's intrinsic insensitivity to interference from electromagnetic fields renders it suitable for clinical CMR.
authors.affiliation: Department of Diagnostic Radiology, University Hospital, RWTH Aachen, Pauwelsstrasse 30, 52074 Aachen, Germany.
authors.forename: Meike
authors.initials: M
authors.lastname: Becker
authors.forename: Tobias
authors.initials: T
authors.lastname: Frauenrath
authors.forename: Fabian
authors.initials: F
authors.lastname: Hezel
authors.forename: Gabriele A
authors.initials: GA
authors.lastname: Krombach
authors.forename: Ute
authors.initials: U
authors.lastname: Kremer
authors.forename: Benedikt
authors.initials: B
authors.lastname: Koppers
authors.forename: Christoph
authors.initials: C
authors.lastname: Butenweg
authors.forename: Andreas
authors.initials: A
authors.lastname: Goemmel
authors.forename: Jane F
authors.initials: JF
authors.lastname: Utting
authors.forename: Jeanette
authors.initials: J
authors.lastname: Schulz-Menger
authors.forename: Thoralf
authors.initials: T
authors.lastname: Niendorf
mesh_terms: D000328:Adult; D055424:Cardiac-Gated Imaging Techniques / Q000379:methods*; D004562:Electrocardiography / Q000379:methods*; D005260:Female; D006801:Humans; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D008297:Male; D008875:Middle Aged; D010701:Phonocardiography / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D018487:Ventricular Dysfunction, Left / Q000175:diagnosis*; D055815:Young Adult