Biomedical Engineering Reference
In-Depth Information
Figure 21.
Three orthogonal 2D images of the atlas and the real tumor patient before
and after deformable registration. Some labels associated with the atlas image are warped
and superimposed on the patient's images. Left to right: atlas image with all labels; atlas
image with five selected labels near the tumor area; patient's image; patient's image with
superimposed labels warped from the atlas via direct deformable registration between the
two images; and the patient's image with superimposed labels warped from the atlas via
the proposed approach. The five selected labels are: the right middle frontal gyrus (green),
the right medial frontal gyrus (dark green), the right superior frontal gyrus (cyan), the
right cingulate region (magenta), and the left cingulate region (brown). Copyright c
2006,
Elsevier B. V. See attached CD for color version.
the available computer memory size, with the relatively small number of available
training samples, statistical models constructed using PCA are sensitive to data
noise and may be unable to generalize to valid shape or deformation instances not
used during training. Here, to deal with this problem, the statistical properties
of only a part of the atlas domain immediately outside
M
A
was modeled. This
region was obtained by several iterations of morphological dilation of region
M
A
followed by subtraction of
M
A
from the resulting region. The number of voxels
in the modeled region of the atlas domain was typically a few thousand voxels
(
≈
5000).
In Figure 21, the results of applying the proposed approach to register the
image of the real tumor subject to the atlas is demonstrated. With the use of
deformable registration to directly register the (normal) atlas image to the patient's
MR image, the warping result is innaccurate in the tumor area. Gray matter from
the right cingulate region and adjacent cortical CSF in the atlas were stretched to
match the intensity of the tumor and the surrounding edema in the patient's image.
The area
M
A
where the registration is inaccurate was outlined manually.
