Cardiovasc Imaging Asia.  2017 Jan;1(1):78-85. 10.22468/cvia.2016.00087.

Semiautomated Analysis of Aortic Stenosis Parameters on Velocity-Encoded Phase-Contrast MR Images in Patients with Severe Aortic Stenosis: A Comparison with Echocardiography

• Bak SH
• Kim SM
• Park SJ
• Kim MY
• Kim HJ
• Lee SC
• Park SW
• Choe YH

• KMID: 2524833
• DOI: http://doi.org/10.22468/cvia.2016.00087

Abstract

Objective
The aim of the study was to determine the reliability of semiautomated analysis of aortic stenosis (AS) parameters on velocity-encoded (VENC) phase-contrast (PC) MR images in patients with severe AS.
Materials and Methods
This study included 55 patients with severe AS and normal left ventricular ejection fraction who underwent transthoracic echocardiography (TTE) and VENC PC sequencing. Aortic valve area (AVA) and transvalvular velocity were measured semiautomatically with commercial software at three aortic valve levels [the level of the aortic leaflet tips (0 mm) and 6 mm upstream and downstream of the leaflet tips]. The AVA was drawn on VENC PC images, and the maximum, minimum, and average were calculated. The peak and mean transaortic pressure gradient (PG) were calculated with a modified Bernoulli equation. All estimates were compared with TTE values by using the concordance correlation coefficient (CCC).
Results
Estimates at the 0 mm level were more highly correlated with TTE values (parameter, CCC): peak velocity, 0.394; average AVA, 0.735; maximum AVA, 0.538; peak PG, 0.539; and mean PG, 0.048. Among these parameters, average AVA 0_mm had the highest reliability.
Conclusion
If AS parameters are measured on VENC PC sequences, average AVA 0_mm should be considered as a parameter for diagnosing severe AS.

Keyword

Aortic stenosis; Valvular heart disease; Magnetic resonance imaging; Transthoracic echocardiography