Objectives: For evaluation of aortic valve area (AVA), transthoracic echocardiography (TTE) is the method of choice. Cardiac magnetic resonance (CMR) at 1.5-Tesla is an alternative. The aim of the study was to check whether quantification of whole range of AVA without severe aortic stenosis is possible and reliable in higher magnetic field strength, and also including a comparison to TTE.
Methods: In 3-T CMR phase contrast sequences were assessed above aortic valve and left ventricular output tract. AVA was calculated using the continuity equation. Planimetric analysis of AVA was performed in magnitude images. TTE was used as reference method for graduation of AVA.
Results: Totally 48 patients (64 ± 18 years) without severe aortic valve stenosis were prospectively enrolled. In CMR planimetric AVA was 2.5 ± 1.3 cm(2) and calculated AVA 2.4 ± 1.3 cm(2), whereas AVA in TTE was 1.9 ± 1.1 cm(2). Planimetric and calculated AVA in CMR and also AVA in CMR and TTE showed good correlation (r = 0.97, 0.92, respectively). Bland-Altman analysis demonstrated no signs of over- or underestimation. Inter- and intraobserver variabilities were low.
Discussion: Determination of AVA using 3-T CMR is possible using direct planimetry and continuity equation. CMR is the alternative first choice method in cases with discrepant or insufficient echocardiographic results.
Keywords: CMR; aortic stenosis; aortic valve; echocardiography.