Segmentation of the aortic leaflets in 3D echocardiographic images

Given the importance of image-based morphological assessment in the diagnosis and surgical treatment of aortic valve disease, there is considerable need to develop a standardized framework for 3D valve segmentation and shape representation. Towards this goal, this work integrates template-based medial modeling and multi-atlas label fusion techniques to automatically delineate and quantitatively describe aortic leaflet geometry in 3D echocardiographic images, a challenging task that has been explored only to a limited extent. The method makes use of expert knowledge of aortic leaflet image appearance, generates segmentations with consistent topology, and establishes a shape-based coordinate system on the aortic leaflets that enables standardized automated measurements.

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(Left) Schematic of the aortic cusps at systole. The valve orifice is the area enclosed by the cusp free edges, and the virtual basal ring connects the basal attachments of the cusps. Valve height is the distance between the virtual basal ring and valve orifice, shown by the black arrow pointing in the direction of blood flow. Three manually identified landmarks are shown in blue. (Right) The triangulated medial template of the aortic cusps used to initialize deformable modeling. (RC = right coronary cusp, LC = left coronary cusp, NC = noncoronary cusp)

 

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A manual segmentation, consensus segmentation generated by label fusion, and fitted medial model of the aortic leaflets. The model-based segmentation is shown in red (right). The yellow arrow points in the direction of blood flow. (LC, RC, NC = left, right, and non-coronary cusps)

The development of this automated technique is a step towards creating a practical, informative tool for preoperative assessment of patient-specific aortic valve morphology.

  • A. M. Pouch, H. Wang, M. Takabe, B. M. Jackson, C. M. Sehgal, J. H. Gorman 3rd, R. C. Gorman, and P. A. Yushkevich, “Automated segmentation and geometrical modeling of the tricuspid aortic valve in 3D echocardiographic images.,” Med Image Comput Comput Assist Interv, vol. 16, iss. Pt 1, pp. 485-492, 2013.
    [Bibtex]
    @ARTICLE{Pouch2013MICCAI,
    author = {Pouch, Alison M. and Wang, Hongzhi and Takabe, Manabu and Jackson,
    Benjamin M. and Sehgal, Chandra M. and Gorman, 3rd, Joseph H and
    Gorman, Robert C. and Yushkevich, Paul A.},
    title = {{A}utomated segmentation and geometrical modeling of the tricuspid
    aortic valve in 3{D} echocardiographic images.},
    journal = {{M}ed {I}mage {C}omput {C}omput {A}ssist {I}nterv},
    year = {2013},
    volume = {16},
    pages = {485--492},
    number = {Pt 1},
    abstract = {The aortic valve has been described with variable anatomical definitions,
    and the consistency of 2D manual measurement of valve dimensions
    in medical image data has been questionable. Given the importance
    of image-based morphological assessment in the diagnosis and surgical
    treatment of aortic valve disease, there is considerable need to
    develop a standardized framework for 3D valve segmentation and shape
    representation. Towards this goal, this work integrates template-based
    medial modeling and multi-atlas label fusion techniques to automatically
    delineate and quantitatively describe aortic leaflet geometry in
    3D echocardiographic (3DE) images, a challenging task that has been
    explored only to a limited extent. The method makes use of expert
    knowledge of aortic leaflet image appearance, generates segmentations
    with consistent topology, and establishes a shape-based coordinate
    system on the aortic leaflets that enables standardized automated
    measurements. In this study, the algorithm is evaluated on 11 3DE
    images of normal human aortic leaflets acquired at mid systole. The
    clinical relevance of the method is its ability to capture leaflet
    geometry in 3DE image data with minimal user interaction while producing
    consistent measurements of 3D aortic leaflet geometry.},
    institution = {{D}epartment of {R}adiology, {U}niversity of {P}ennsylvania, {P}hiladelphia,
    {PA}, {USA}.},
    language = {eng},
    medline-pst = {ppublish},
    owner = {alison},
    pmid = {24505702},
    timestamp = {2014.02.27}
    }

Coming soon…

Segmentation of the complete aortic valve apparatus (cusps and root) with branching medial models.

av-apparatus-template

Aortic valve complex shown from three viewpoints: side (left), ventricular (center), and aortic (right) perspectives. (STJ = sinotubular junction, LVO = left ventricular outflow)