title: Magnetic resonance jet velocity mapping in mitral and aortic valve stenosis.
abstract: BACKGROUND
  Magnetic resonance (MR) phase-shift velocity mapping is an established method for measurement of nonturbulent intravascular flow. Shortening the echo time of the MR sequence to 3.6 msec allowed application of the technique to turbulent jet flow. The objective of this study was validation of MR jet velocity mapping in patients with cardiac valve stenosis.
  
  
  RESULTS
  We used a 0.5-T Picker MR machine to measure peak poststenotic jet velocity in 15 consecutive patients recruited with known valve disease (six mitral stenosis, three of these restudied after valvoplasty, and 11 aortic stenosis). On the same day as the MR study, these patients underwent independent Doppler echocardiographic measurement of peak jet velocity. The results of 10 further MR investigations of aortic stenosis are also reported and compared with Doppler studies performed within 6 months. Of the 29 MR studies, 28 (97%) produced interpretable velocity maps, the one failure being attributed to misplacement of the imaging slice in a case of severe aortic stenosis. Agreement between MR and Doppler measurements of peak jet velocity in the recruited group was as follows: n = 18; range, 1.4-6.1 m/sec; mean, 3 m/sec; mean of differences (MR-Doppler), 0.23 m/sec; standard deviation of differences, 0.49 m/sec.
  
  
  CONCLUSIONS
  In vivo MR peak jet velocity measurements agree well with those made by Doppler ultrasound. The technique, which is not subject to restricted windows of access and has potential for further refinements, could contribute to improved evaluation of stenoses, especially at locations where ultrasonic access is limited.
authors: Magnetic Resonance Unit, Royal Brompton National Heart and Lung Hospital, London, UK.
authors: P J
authors: PJ
authors: Kilner
authors: C C
authors: CC
authors: Manzara
authors: R H
authors: RH
authors: Mohiaddin
authors: D J
authors: DJ
authors: Pennell
authors: M G
authors: MG
authors: Sutton
authors: D N
authors: DN
authors: Firmin
authors: S R
authors: SR
authors: Underwood
authors: D B
authors: DB
authors: Longmore
mesh_terms: D001024:Aortic Valve Stenosis / Q000175:diagnosis* / Q000503:physiopathology; D001783:Blood Flow Velocity / Q000502:physiology; D003326:Coronary Circulation / Q000502:physiology; D015150:Echocardiography, Doppler; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D008946:Mitral Valve Stenosis / Q000175:diagnosis* / Q000503:physiopathology; D015203:Reproducibility of Results