Jos Westenberg PhD, Abstract Co-Author: Nothing to Disclose

Stijntje Dorien Roes MD, Abstract Co-Author: Nothing to Disclose

Nico Binnendijk, Abstract Co-Author: Nothing to Disclose

Albert De Roos MD, Abstract Co-Author: Nothing to Disclose

Johan H.C. Reiber PhD, Abstract Co-Author: Nothing to Disclose

Rob J. van der Geest MS, Presenter: Nothing to Disclose

Although conventional one-directional (1-dir) velocity-encoded (VE) MRI is routinely used for flow assessment over mitral (MV) and tricuspid valve (TV), it has been shown to be inaccurate. Three-dimensional (3D) 3-dir VE MRI with retrospective valve tracking during offline analysis is introduced for simultaneous MV and TV-flow assessment.

MRI was performed on a Gyroscan ACS/NT15 (Philips, Best, the Netherlands). A 3D acquisition with 3-dir VE MRI was designed and tested in stationary flow phantoms and in a phantom simulating harmonic left ventricular filling. Echo Planar Imaging (EPI) was used for acceleration.In ten volunteers without regurgitation, MV and TV-flow was assessed from the 3D velocity vector field of the blood flow acquired at the basal level of the heart and reconstructed into 30 phases/cardiac cycle (velocity sensitivity set to 150 cm/s). In offline analysis, MV and TV-flow was reformatted using left and right ventricular cine 2- and 4-chamber views (in 30 corresponding phases/cardiac cycle). Analysis was repeated by two observers to test intra- and inter-observer variation. 1-dir VE MRI was performed for comparison.Finally, MV and TV-flow was assessed in ten patients with valve regurgition.

Phantom validation showed less than 10% error in flow quantification for either 3D VE MRI or 1-dir VE MRI. In volunteers, a significant bias was found for 1-dir VE MRI for both MV (over-estimation 11 ml/cycle) and TV (over-estimation 12 ml/cycle), while 3D VE MRI showed no bias and small confidence intervals. Correlation with aortic flow was strong for 3D VE MRI (r=0.96 for MV, r=0.88 for TV; r=0.91 between MV and TV) but weak for 1-dir VE MRI (r=0.70 for MV, r=0.21 for TV; r=0.34 between MV and TV). Coefficient of variation for 3D VE MRI was 4% for intra- and 6% for inter-observer analysis. Also in patients, correlation with aortic flow was strong (r=0.94 for MV, r=0.78 for TV; r=0.84 between MV and TV).

3D VE MRI provides true trans-valvular MV and TV-flow in a single acquisition in less than 5 minutes scan time.

Regurgitation through atria-ventricular valves can be accurately quantified, providing essential information for surgical decision-making.

Westenberg, J, Roes, S, Binnendijk, N, De Roos, A, Reiber, J, van der Geest, R, Accurate Quantification of True Transvalvular Flow Simultaneously over Mitral and Tricuspid Valve Using 3D Velocity-encoded MRI with Retrospective Valve Tracking.  Radiological Society of North America 2007 Scientific Assembly and Annual Meeting, November 25 - November 30, 2007 ,Chicago IL. http://archive.rsna.org/2007/5010362.html