Clinical assessment of aortic valve stenosis: comparison between 4D flow MRI and transthoracic echocardiography

Background The prevalence of valvular aortic stenosis (AS) increases as the population ages. Echocardiographic measurements of peak jet velocity (V-peak), mean pressure gradient (P-mean), and aortic valve area (AVA) determine AS severity and play a pivotal role in the stratification towards valvular replacement. A multimodality imaging approach might be needed in cases of uncertainty about the actual severity of the stenosis. Purpose To compare four-dimensional phase-contrast magnetic resonance (4D PC-MR), two-dimensional (2D) PC-MR, and transthoracic echocardiography (TTE) for quantification of AS. Study Type Prospective. Population Twenty patients with various degrees of AS (69.3 +/- 5.0 years). Field Strength/Sequences 4D PC-MR and 2D PC-MR at 3T. Assessment We compared V-peak, P-mean, and AVA between TTE, 4D PC-MR, and 2D PC-MR. Flow eccentricity was quantified by means of normalized flow displacement, and its influence on the accuracy of TTE measurements was investigated. Statistical Tests Pearson's correlation, Bland-Altman analysis, paired t-test, and intraclass correlation coefficient. Results 4D PC-MR measured higher V-peak (r = 0.95, mean difference + 16.4 +/- 10.7%, P