title: Doppler ultrasound compared with electrocardiogram and pulse oximetry cardiac triggering: A pilot study.
abstract: OBJECTIVE
  Accurate triggering of the cardiac cycle is mandatory for optimal image acquisition and thus diagnostic quality in cardiac magnetic resonance imaging. The purpose of this work was to evaluate Doppler ultrasound as an alternative trigger method in cardiac MRI.
  
  
  METHODS
  Steady-state free precession (SSFP) 2D cine CMR was performed in 11 healthy subjects at 1.5T. Doppler ultrasound (DUS), electrocardiogram (ECG) and pulse oximetry (POX) were used for cardiac triggering. DUS peak detection was verified in comparison to ECG. Quantitative analysis of image quality of each gating method was determined by calculating endocardial border sharpness (EBS) and left ventricular (LV) function parameters and compared with ECG.
  
  
  RESULTS
  Mean difference between DUS and ECG in detected RR intervals was 0.04 ± 63 ms (r = 0.96). Trigger jitter was not different between ECG and DUS (P = 0.15) but significant different between ECG and POX (P = 0.01). EBS was similar between each method (3.1 ± 0.2 / 2.6 ± 0.2 / 2.9 ± 0.2 pixel). Mean differences in stroke volume were not significantly different with -1 ± 7 mL (ECG/DUS, P = 0.9) and 2 ± 10 mL (ECG/POX, P = 0.8).
  
  
  CONCLUSIONS
  Cine cardiac MRI using DUS was successfully demonstrated. DUS triggering is an alternative method for cardiac MRI and may be applied in a clinical setting.
authors.affiliation: University Medical Centre Hamburg-Eppendorf, Centre for Radiology and Endoscopy, Department of Diagnostic and Interventional Radiology, Germany.
authors.forename: Fabian
authors.initials: F
authors.lastname: Kording
authors.affiliation: University Medical Centre Hamburg-Eppendorf, Centre for Radiology and Endoscopy, Department of Diagnostic and Interventional Radiology, Germany.
authors.forename: Bjoern
authors.initials: B
authors.lastname: Schoennagel
authors.affiliation: University Medical Centre Hamburg-Eppendorf, Centre for Radiology and Endoscopy, Department of Diagnostic and Interventional Radiology, Germany.
authors.forename: Gunnar
authors.initials: G
authors.lastname: Lund
authors.affiliation: Hamburg University of Applied Sciences, Hamburg, Germany.
authors.forename: Friedrich
authors.initials: F
authors.lastname: Ueberle
authors.affiliation: University Medical Centre Hamburg-Eppendorf, Centre for Radiology and Endoscopy, Department of Diagnostic and Interventional Radiology, Germany.
authors.forename: Caroline
authors.initials: C
authors.lastname: Jung
authors.affiliation: University Medical Centre Hamburg-Eppendorf, Centre for Radiology and Endoscopy, Department of Diagnostic and Interventional Radiology, Germany.
authors.forename: Gerhard
authors.initials: G
authors.lastname: Adam
authors.affiliation: University Medical Centre Hamburg-Eppendorf, Centre for Radiology and Endoscopy, Department of Diagnostic and Interventional Radiology, Germany.
authors.forename: Jin
authors.initials: J
authors.lastname: Yamamura
mesh_terms: D000328:Adult; D000465:Algorithms; D057791:Cardiac Imaging Techniques; D004562:Electrocardiography / Q000379:methods*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008297:Male; D010092:Oximetry / Q000379:methods*; D010865:Pilot Projects; D012815:Signal Processing, Computer-Assisted; D018608:Ultrasonography, Doppler / Q000379:methods*
keywords: Doppler ultrasound; cardiac-gated imaging techniques; cine magnetic resonance imaging; computer-assisted image processing; electrocardiogram; oximetry