title: Inline directionally independent peak velocity evaluation reduces error in peak antegrade velocity estimation in patients referred for cardiac valvular assessment.
abstract: OBJECTIVE
  The purpose of this article is to evaluate the utility of a tool in quantifying the peak antegrade velocity when assessing patients with cardiac valvular pathology.
  
  
  METHODS
  Directionally independent peak velocity evaluation (MaxVelocity, Siemens Healthcare) phase-contrast cardiac MRI was performed for 44 patients referred to our institution with a diagnosis or concern for aortic valvular disease or undergoing imaging for thoracic aortic aneurysm. In addition, standard through-plane phase-contrast MR angiography at the level of the aortic valve was performed. The MaxVelocity technique provides a simple tool to extract the magnitude of the peak velocity, independently of its direction, from phase-contrast imaging with velocity encoding. Recent echocardiography (within 1 month) and assessment of peak forward velocity at the level of the aortic valve were required for inclusion in the study.
  
  
  RESULTS
  The MaxVelocity technique shows significantly lower error in estimating peak antegrade velocity at the level of the aortic valve than does standard unidirectional through-plane phase-contrast MRI, using transthoracic echocardiography as the reference noninvasive imaging method.
  
  
  CONCLUSIONS
  Relative to standard through-plane imaging, MaxVelocity more closely approximates echocardiography for noninvasive assessment of peak antegrade velocity. Improved accuracy is critical for surgical decision making in patients with aortic valvular disease. Therefore, MaxVelocity provides an easy approach to quantify peak velocity as part of a routine clinical MRI protocol.
authors.affiliation: Division of Cardiovascular Imaging, Northwestern Memorial Hospital, Chicago, IL, USA. Philip.Hodnett@hse.ie
authors.forename: Philip A
authors.initials: PA
authors.lastname: Hodnett
authors.forename: Christopher B
authors.initials: CB
authors.lastname: Glielmi
authors.forename: Amir H
authors.initials: AH
authors.lastname: Davarpanah
authors.forename: Timothy G
authors.initials: TG
authors.lastname: Scanlon
authors.forename: Emily
authors.initials: E
authors.lastname: Ward
authors.forename: Jeremy D
authors.initials: JD
authors.lastname: Collins
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Weale
authors.forename: James C
authors.initials: JC
authors.lastname: Carr
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D017545:Aortic Aneurysm, Thoracic / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000503:physiopathology; D001783:Blood Flow Velocity / Q000502:physiology*; D015150:Echocardiography, Doppler; D005260:Female; D006349:Heart Valve Diseases / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000503:physiopathology; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008875:Middle Aged; D012984:Software