Abstract 2029: Head-to-Head Comparison of Planimetric and Continuity Equation Assessment of Aortic Valve Area by Cardiac Magnetic Resonance and Echocardiography.
Purpose. Similar to echocardiography, cardiac MR (cMR) can assess aortic valve area (AVA) by a direct planimetric and a continuity equation approach. Yet, both approaches have never been compared in the same patient population. Accordingly, the aim of the present study was to compare planimetric and continuity equation AVA obtained by cMR and echocardiography.
Methods. Thirty-eight patients (27 males, mean age: 60±13 yrs) underwent cMR, transtho-racic (TTE) and transesophageal (TEE) echocardiography prior to cardiac surgery. Planimetry of maximal AVA opening was performed with TEE and on steady-state free precession cine breathold cMR images through the aortic valve. Continuity equation AVA was computed using velocity time integrals from TTE and phase-contrast imaging at the level of the valve tips and the left ventricular outflow tract (LVOT).
Results. Data are summarized in the table⇓. Planimetric and continuity equation AVA by cMR and echo were highly correlated. Planimetric AVA by cMR and TEE were similar but significantly higher than continuity equation AVA by both techniques. Similarly, continuity equation AVA by cMR and TTE were not significantly different but lower than planimetric AVA by TEE and cMR.
Conclusion. cMR can accurately assess AVA both by planimetry and continuity equation. Yet, these 2 measurements differ significantly. Indeed, similar to TEE, cMR AVA was larger by planimetry than by the continuity equation. This is consistent with the contention that the anatomical maximum opening of a stenotic aortic valve is larger than the size of the functional vena contracta.