Usefulness of 3-Tesla cardiac magnetic resonance imaging in the assessment of aortic stenosis severity in routine clinical practice

Abstract

Recently, 1.5-Tesla cardiac magnetic resonance imaging (CMR) was reported to provide a reliable alternative to transthoracic echocardiography (TTE) for the quantification of aortic stenosis (AS) severity. Few data are available using higher magnetic field strength MRI systems in this context. To evaluate the feasibility and reproducibility of the assessment of aortic valve area (AVA) using 3-Tesla CMR in routine clinical practice, and to assess concordance between TTE and CMR for the estimation of AS severity. Ninety-one consecutive patients (60 men; mean age 74±10years) with known AS documented by TTE were included prospectively in the study. All patients underwent comprehensive TTE and CMR examination, including AVA estimation using the TTE continuity equation (0.81±0.18cm2), direct CMR planimetry (CMRp) (0.90±0.22cm2) and CMR using Hakki's formula (CMRhk), a simplified Gorlin formula (0.70±0.19cm2). Although significant agreement with TTE was found for CMRp (r=0.72) and CMRhk (r=0.66), CMRp slightly overestimated (bias=0.11±0.18cm2) and CMRhk slightly underestimated (bias=-0.11±0.17cm2) AVA compared with TTE. Inter- and intraobserver reproducibilities of CMR measurements were excellent (r=0.72 and r=0.74 for CMRp and r=0.88 and r=0.92 for peak aortic velocity, respectively). 3-Tesla CMR is a feasible, radiation-free, reproducible imaging modality for the estimation of severity of AS in routine practice, knowing that CMRp tends to overestimate AVA and CMRhk to underestimate AVA compared with TTE.