GE Voluson S6 Basic User Manual page 335

9.12.1 Definitions
Voluson® S6/S8 Basic User Manual
5433669-100 Revision 4
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Manual or Semi automatic Contour detection of structures (such as tumor lesion, cyst,
prostate, etc.) and subsequent volume calculation. The accuracy of the process can be
visually controlled by the examiner in multi-planar display.
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Construction of a virtual shell around the contour of the lesion. The wall thickness of the
shell can be defined. The shell can be imagined as a layer of tissue around the lesion,
where the tumor vascularization takes place.
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Automatic calculation of the vascularization within the shell by 3D color histogram by
comparing the number of color voxels to the number of grayscale voxels.
The follow-up control of tumor volume and vascularization delivers information on the proper
dose of medication or radiation and is therefore a measure for the success of treatment. After
definition of a contour in 3D space a wide range of functionality is given:
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definition of a shell contour
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visualization of a (shell) contour as a surface or wire mesh
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volume calculation of a (shell) contour
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histogram calculation of ultrasound tissue inside a (shell) contour
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visualization of ultrasound tissue inside a (shell) contour as a rendered image
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niche presentation of contour and slices
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cine rotation calculation
The basic idea behind VOCAL II is the combination of 3D ultrasound tissue (presented as
voxels) and the geometric information of surfaces in a 3D dataset. The main interest of
VOCAL II is the volume calculation of tumors or lesions.
The principle operation steps are given in this diagram.
Definition of the Surface Geometry
Surface Geometry is defined by rotation of an image plane about a fixed axis (main
The
contour axis) and the definition of 2D contours in each plane. The 2D contours can be defined
semi-automatically (Contour Finder), manually or by an automatic sphere. The rotation step for
each contour plane depends on the VOCAL Mode and on the selected rotation steps.
Surface Geometry is defined by 3D triangularization of the 2D contours, meaning each
The
point of the 2D contour in plane N is connected via a triangle mesh to corresponding points in
plane N-1 and plane N+1.
Volume Mode
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