Biomedical Engineering Reference
In-Depth Information
minima due to the forward deformation mapping is reported by Klein. Because of
these drawbacks, we do not consider such methods based on forward mapping in
the following.
1.5.4
Diffeomorphic Registration
In medical image registration, diffeomorphic transformations are imperative as they
are invertible, smooth, orientation preserving, and free of foldings. Recently, several
approaches were developed to ensure diffeomorphisms [
2
,
5
,
97
,
117
,
132
]. Inspired
by the Jacobian determinant in V
AMPIRE
, we derived a new discretization of a
hyperelastic regularizer [
22
] that is now integrated in the F
AIR
registration tool-
box [
95
]. It directly controls the volumetric change which in our case corresponds
to the intensity modulations. Although it is a key feature of V
AMPIRE
, it can also
be used for any other registration task. The main ideas of this regularizer are
summarized in Sect.
2.1.2.3
.
1.6
Visualization
For the illustration of the data we will use two different visualizations in terms of
body planes
and
cardiac planes
. To better understand their location with respect to
the patient they will be introduced briefly below. The global body planes are
1.
Sagittal
,
2.
Coronal
, and
3.
Transverse
.
The transverse plane is also often denoted as the
axial plane
in the literature.
An illustration is given in Fig.
1.13
.
Apart from the global body planes we will also use cardiac planes which are
given by the
1.
Short Axis
(SA),
2.
Horizontal Long Axis
(HLA), and the
3.
Vertical Long Axis
(VLA).
The cardiac planes are visualized in Fig.
1.14
. The cardiac planes are especially
informative for physicians as they are given in the coordinate system of the
heart. However, as for example respiratory motion is primarily in the craniocaudal
direction, which can be nicely visualized by the coronal or sagittal plane, we will
use all representations throughout this topic.
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