Mitral stenosis refers to stenosis of the mitral valve in the heart.
It is characterised by restriction of blood flow from the left atrium to the left ventricle as a result of a narrowed mitral passage. Mitral stenosis is usually an acquired valvular defect and historically, the commonest cause has been rheumatic heart disease. However, cases of congenital mitral stenosis are occasionally encountered.
- extensive mitral annular calcification particularly in older people can result in mitral stenosis
A widely adopted echocardiographic scoring system that Wilkins and colleagues developed helps in patient selection. In this system, 4 features of the mitral valve are identified, as follows:
- valve leaflet mobility
- valve thickening
- valve calcification
- sub-valvular involvement
Chest radiographs may show:
- double right heart border (enlarged left atrium and normal right atrium)
- prominent left atrial appendage
- splaying of the subcarinal angle (>120 degrees)
Non-rheumatic causes of mitral stenosis usually produce nonspecific imaging features such as valve thickening or leaflet fixation.
Associated features include:
Dynamic CT imaging
Restricted opening of the thickened valve from commissural fusion (especially with rheumatic valve disease), valve calcification, or both results in a “fish-mouth” appearance on short-axis images. Bowing of a thickened and fibrotic anterior leaflet during diastole may result in a “hockey-stick” appearance which is best seen on two- or four-chamber images 1.
May contribute to the non-invasive assessment of mitral stenosis 6.
Observable features include:
- mitral leaflet thickening
- reduced diastolic opening
- abnormal valve motion toward the left ventricular outflow tract
Velocity-encoded cine-magnetic resonance imaging (VEC-MRI) is a new method for quantitation of blood flow with the potential to measure high-velocity jets across stenotic valves 5-7.
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