Information Technology Reference
In-Depth Information
3
S
Fig. 2 The spine-based coordinate system
of a 3D image of a scoliotic spine,
shown in a 3D view, b left sagittal view, c posterior coronal view and d superior axial view (Note
The spine corresponds to Fig.
1
)
!ð
u
;
v
;
w
Þ
R
C
:
c
ð
i
Þ
¼
ð
c
x
ð
i
Þ;
c
y
ð
i
Þ;
c
z
ð
i
ÞÞ;
i
2
½
i
sp
;
i
ep
;
ð
1
Þ
where i
i
ep
represent the locations on the spine at its start and end
point of observation, respectively, and c
x
ð
¼
i
sp
and i
¼
represent the sagittal,
coronal and axial coordinate, respectively, of the same anatomical reference point at
any location i on the spine in the image-based coordinate system. Although arbi-
trary anatomical reference points can be chosen (e.g. the centers of the spinal canal),
the most established anatomical reference points are the centers of vertebral bodies.
For K observed consecutive vertebrae, let points
i
Þ
, c
y
ð
i
Þ
and c
z
ð
i
Þ
f
v
ð
k
Þ
¼
ð
v
x
ð
k
Þ;
v
y
ð
k
Þ;
v
z
ð
k
ÞÞ;
k
¼
1
;
2
; ...;
K
g
represent the corresponding centers of vertebral bodies. The spine