Effective orifice area assessment in BI-leaflet mechanical valves by MRI,

Morgan Evin (1) , A. Lalande (2) , David Joannic (2) , J.-F. Fontaine (2) , Yufei Wang (2) , D. F. Fletcher (3) , D.F. Callaghan (1) , Sm Grieve (1, 4)

1 The University of Sydney
2 Le2i - Laboratoire Electronique, Informatique et Image [UMR6306]
3 School of Chemical and Biomolecular Engineering
4 RNSH - Royal North Shore Hospital

Effective orifice area (EOA) and mean pressure gradient are routine echocardiographic measurements of valvular prosthesis function in both the mitral and aortic position. EOA computation is based on the continuity equation and is used to describe the “effective” orifice formed by the flow traversing a geometrical orifice. In the case of bi-leaflet biomechanical valvular prosthesis (BMHV), the orifice of the valve is divided into 3 zones. BMHV performance assessment by MRI have been described in the in-vitro setting in [1] using the maximum pressure gradient. Additionally, a method using jet layer has been used to detect EOA dynamically [2]. 4D-PC flow sequences enable measurement of three velocity components by MRI with a temporal resolution averaging (~ 30 msec). In patients with a BMHV, despite the metallic blurring due to the valve structure, MRI examination enhances both anatomical and hemodynamic diagnosis. Aim of this work is to assess the capacity of MRI to measure BMHV EOA by 4D-PCflow MRI, using simple computational fluid dynamic (CFD) simulation for validation.

Domaines: Génie mécanique [physics.class-ph]

Morgan Evin, A. Lalande, David Joannic, J.-F. Fontaine, Yufei Wang, et al.. Effective orifice area assessment in BI-leaflet mechanical valves by MRI,. European Society of Biomechanic congress, Jul 2016, LYON, France. ⟨hal-01463885⟩