Quantification of valvular aortic stenosis by magnetic resonance imaging

Planimetric and continuity equation assessment of aortic valve area: Head to head comparison between cardiac magnetic resonance and echocardiography

“…Several recent studies have compared the measurements of AVA obtained by this planimetric approach with those obtained by TEE or during cardiac catheterization. All demonstrated good agreement between cMR and either TTE or hemodynamic measurements of AVA (3)(4)(5)(6). Potential limitations of planimetry consist of difficulties of precise visualization of the aortic leaflets due to partial volume effects, presence of calcification, or flow artifacts.…”

“…With the introduction of SSFP, this technique indeed permits high quality cine short-axis images of the aortic valve to be obtained and therefore its maximal opening area to be directly planimetered (3)(4)(5)(6). Several recent studies have compared the measurements of AVA obtained by this planimetric approach with those obtained by TEE or during cardiac catheterization.…”

“…SIMILAR TO ECHOCARDIOGRAPHY, cardiac MRI (cMR) allows for the assessment of aortic stenosis (AS) severity by use of two different approaches, i.e., the direct planimetry of the maximal anatomical orifice using cine MR imaging at the valve tips (1)(2)(3)(4)(5)(6) and the calculation of the functional orifice area using the continuity equation and velocity time integrals (VTIs) obtained at the valve tips and the left ventricular outflow tract with phase-contrast imaging (7,8). Although aortic valve areas (AVAs) obtained with both techniques have been shown to correlate well with echocardiography and the Gorlin formula, there has been no direct comparison of these two approaches in the same population.…”

The emerging clinical role of cardiovascular magnetic resonance imaging

“…Aortic valve stenosis can be accurately quantified by planimetry of the aortic valve (96,97) (Figure 4), a method that does not depend on pressure gradient measurement-derived calculations, and that therefore may be less susceptible to pre-and afterload variations. Another established way to assess the aortic valve area is by flow measurements using phase-contrast CMR imaging, analogous to Doppler echocardiography.…”

“…The accuracy of phase-contrast measurements as assessed with in vitro models is excellent (91,92) and good correlations have been documented between CMR flow measurements and Doppler echocardiography (93), as well as cardiac catheterization (94,95). Cine imaging is applied to quantify the orifice of a stenotic valve (96).…”