J Korean Med Sci.  2009 Apr;24(2):203-208. 10.3346/jkms.2009.24.2.203.

Does The Mitral Annulus Shrink or Enlarge During Systole? A Real-Time 3D Echocardiography Study

• Kwan J
• Jeon MJ
• Kim DH
• Park KS
• Lee WH

• KMID: 1779119
• DOI: http://doi.org/10.3346/jkms.2009.24.2.203

Abstract

This study was conducted to explore the geometrical changes of the mitral annulus during systole. The 3D shape of the mitral annulus was reconstructed in 13 normal subjects who had normal structure of the mitral apparatus using real-time 3D echocardiography (RT3DE) and 3D computer software. The two orthogonal (antero-posterior and commissure-commissure) dimensions, the areas (2D projected and 3D surface) and the non-planarity of the mitral annulus were estimated during early, mid and late systole. We demonstrated that the MA had a "saddle shape" appearance and it consistently enlarged mainly in the antero-posterior direction from early to late systole with lessening of its non-planarity, as was determined by 3D reconstruction using RT3DE and 3D computer software.

Keyword

Mitral Annulus; Echocardiography

MeSH Terms

*Echocardiography, Three-Dimensional
Humans
Image Processing, Computer-Assisted
Mitral Valve/cytology/*ultrasonography
Software
Systole/*physiology

Figure

• 

  Fig. 1 Generation of 16 rotational apical planes and tracing 32 hinge points of the mitral annulus (white spots) on each plane for 3D reconstruction of the annulus using newly developed 3D computer software.

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  Fig. 2 Definition of anatomical reference markers of the mitral annulus on the cross sectional volumetric plane and geometrical measurements of the annulus. A, anterior point; P, posterior point; AC, anterior commissure; PC, posterior commissure; AML, anterior mitral leaflet; PML, posterior mitral leaflet; AP, antero-posterior; CC, commissure-commissure; NPA, non-planar angle.

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  Fig. 3 Division of the mitral annulus into anterior and posterior annuli by the CC axis and the NPA measurement. CC, commissure-commissure; NPA, non-planar angle.

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  Fig. 4 3D reconstruction and 3D area calculation (B) of a "saddle-shaped" artificial structure (A) using newly developed 3D computer software for its validation.

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  Fig. 5 Anterior oblique (left) and projected (right) views of the mitral annulus. A, anterior point; P, posterior point; AC, anterior commissure; PC, posterior commissure.

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  Fig. 6 Line graphs showing changes of the areas (2D and 3D) of the mitral annulus during three phases (early, mid, and late) of the systole. 2DMAA, 2D area of the annulus; 3DMAA, 3D area of the annulus; 3DaMAA, 3D area of the anterior annulus; 3DpMAA, 3D area of the posterior annulus. *p<0.05 versus prior phase by post-hoc comparison test (Bonferroni's method).

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  Fig. 7 Change of the AP dimension of the mitral annulus from early to late systole in comparison with that of the AP diameter of the left ventricle. AP, antero-posterior.

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  Fig. 8 Change of the 3D shape of the mitral annulus from early to late systole. NPA, non-planar angle.

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