title: Motion artifacts in cardiac CT. The Novacor left ventricular assist device and its implications for clinical imaging.
abstract: OBJECTIVE
  Cardiovascular applications of CT are primarily limited by temporal resolution of the scanner. Recent development in scanner technology has greatly increased temporal resolution. We here describe a standardized method of assessing temporal properties of various CT techniques.
  
  
  METHODS
  The Novacor left ventricular assist device was mounted in a water-filled circulation phantom and scanned at different pump rates with a spiral CT unit and an electron beam unit. We also evaluated the use of ECG-triggered subsecond scanning on a spiral CT unit.
  
  
  RESULTS
  Using the fastest conventional scanning protocol, severe motion artifacts occurred. These artifacts could not be reproduced from image to image, even if the pump rate was adjusted to scan rate (l/s). Electron beam tomography (EBT) reproducibly yielded few artifacts at 100 ms and practically no artifacts at 50 ms scanning time. Even without ECG-triggering, pump motion could be reproduced as a cine-cycle. With the ECG-triggered partial scanning CT technique, limited motion artifacts could be reproduced during diastole at a heart rate of 70-80 beats/min.
  
  
  CONCLUSIONS
  The Novacor ventricular assist device may serve as a benchmark test in the evaluation of new scanning techniques for cardiovascular CT. While EBT presently remains the only CT technique to freeze cardiac motion throughout its cycle, ECG-triggered subsecond scans may, under certain conditions, capture cardiac anatomy in diastole.
authors.affiliation: Strahlenklinik, Medizinische Fakultät der Humboldt-Universität zu Berlin, Germany.
authors.forename: F D
authors.initials: FD
authors.lastname: Knollman
authors.forename: R
authors.initials: R
authors.lastname: Halfmann
authors.forename: J
authors.initials: J
authors.lastname: Regn
authors.forename: M
authors.initials: M
authors.lastname: Loebe
authors.forename: R
authors.initials: R
authors.lastname: Ewert
authors.forename: R
authors.initials: R
authors.lastname: Hetzer
authors.forename: R
authors.initials: R
authors.lastname: Felix
mesh_terms: D016477:Artifacts; D004562:Electrocardiography; D006353:Heart-Assist Devices; D008955:Models, Cardiovascular; D015203:Reproducibility of Results; D014057:Tomography, X-Ray Computed / Q000379:methods*