Information Technology Reference
In-Depth Information
coordinate system, the following types of MPR can be applied to 3D images of the
spine:
orthogonal MPR, where the sampling plane is orthogonal to one of the axes of
the image-based coordinate system (Sect.
3.1.1
),
oblique MPR, where the orthogonal sampling plane, de
ned in the image-based
coordinate system, is rotated about the axes of the image-based coordinate
system (Sect.
3.1.2
).
The common characteristic of all types of MPR is that sampling planes are
3
de
ned on the basis of the image-based coordinate system
I
.
R
3.1.1 Orthogonal Multi-planar Reformation
The most common MPR is orthogonal, meaning that the sampling plane is
orthogonal to one of the axes of the image-based coordinate system. By applying
orthogonal MPR to a 3D spine image, the following orthogonal multi-planar cross-
sections can be obtained:
sagittal orthogonal multi-planar cross-sections are obtained by sampling the 3D
image on selected sagittal planes de
ned in the-based coordinate system (sec-
tion
Sagittal Orthogonal Multi-planar Cross-Sections
),
coronal orthogonal multi-planar cross-sections are obtained by sampling the
3D image on selected coronal planes de
ned in the image-based coordinate
system (section
Coronal Orthogonal Multi-planar Cross-Sections
),
axial orthogonal multi-planar cross-sections are obtained by sampling the 3D
image on selected axial planes de
ned in the image-based coordinate system
(section
Axial Orthogonal Multi-planar Cross-Sections
).
I
,
By selecting a point p
c
¼
ð
x
c
;
y
c
;
z
c
Þ
in the image-based coordinate system
R
exactly one sagittal (x
¼
x
c
), one coronal (y
¼
y
c
) and one axial (z
¼
z
c
) orthogonal
multi-planar cross-section can be de
ned through p
c
.Ifp
c
is located on the spine
, the obtained cross-
sections show, depending on the shape of the spine, parts of the spinal anatomy.
curve c
ð
i
Þ
, e.g. at point i
¼
i
p
so that p
c
¼
c
x
ð
i
p
Þ;
c
y
ð
i
p
Þ;
c
z
ð
i
p
Þ
Sagittal Orthogonal Multi-planar Cross-Sections
Sagittal orthogonal multi-planar cross-sections are obtained by sampling the 3D
image on selected sagittal planes that are orthogonal to axis x of the image-based
coordinate system. The sagittal orthogonal multi-planar cross-section M
x¼x
c
is
¼
therefore obtained by selecting a
x
c
, and sampling the 3D
image I along coordinates y and z in the image-based coordinate system:
fixed coordinate x