Exact determination of the orifice area in stenotic valve disease is essential to guide therapy. With the standard imaging methods, the orifice area has to be calculated by empirically-derived formulas, which may be susceptible to changes in hemodynamic status, leading to wrong therapeutic decisions. We tested the ability of magnetic resonance imaging (MRI) to quantify the orifice area by planimetry of the proximal vena contracta (PVC) in an idealized, constant-flow model in a 1.0-T tomograph (Siemens Magnetom Expert). There was a close correlation of the PVC area in MRI and the true orifice area (r2 = 0.985), and agreement of the methods as measured by the Bland-Altman test was significant with a low systematic error of -0.02 cm2. We conclude that MRI planimetry of the PVC in stenotic valves in a constant-flow model may be used to reliably measure the orifice area.
Copyright 2001 Wiley-Liss, Inc.