Biomedical Engineering Reference
In-Depth Information
Figure 5.
Parametric directions of the left- and right-ventricular NURBS model given by
(
u
LV
,v
LV
,w
LV
)
and
(
u
RV
,v
RV
,w
RV
)
, respectively.
Figure 6.
Initial NURBS model of a canine heart constructed from the left- and right-
ventricular contours.
See attached CD for color version.
4.2.2. Left-ventricular NURBS model
Using the concept of a
base surface
[
?
], we construct the left-ventricular model
based on a cylindrical or prolate spheroidal parameter assignment. The selection of
these two particular geometric primitives is a natural choice considering the shape
of the left ventricle. Usage of the base surface concept permits the utilization of
both short- and long-axis contour information in building the model. The origin
of the coordinate system is defined as the center of the short-axis left-ventricular
endocardial contour in the most basal short-axis image slice. The focus (for the
prolate spheroidal parametrization) is placed along the central axis of the left
ventricle at a distance equal to the radius of curvature of the apical point of the
long-axis endocardial contour from the apex.
