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In-Depth Information
Provocative discography may be used to con
rm that a degenerative disk is the
source of neck pain or back pain in dif
uoroscopy, a
diseased disk is injected at a certain pressure to see if this procedure reproduces the
patient
cult cases [
19
]. Under
fl
s pain. If the injection to an adjacent normal disk does not reproduce the
pain, the test is con
'
rmatory.
MRI is the standard imaging modality for detecting disk disease. It is indicated
in patients who have progressive neurological symptoms despite conservative
management, or in patients who plan to undergo surgery. On MRI, a degenerated
disk has decreased intensity on T2 weighted images, due to loss of water content
and glycosaminoglycans [
20
]. Bulging of the annulus (Fig.
5
a), herniation of the
disk contents (Fig.
5
b), and loss of intervertebral disk height can be demonstrated
on MRI. Early changes of disk degeneration, such as tears of the annulus
fibrosis,
can be seen as high intensity zone lesions [
21
,
22
].
CT scan can depict degeneration, bulging and herniation of the disk, but with
much less detail than MRI. CT can also show sclerotic changes of the vertebral
endplate and loss of the disk height, which are commonly seen in degenerative disk
disease, but these
findings most often can be readily seen on plain radiographs.
Clinically, CT is used in patients with contraindications to MRI.
Fig. 5 Degenerative disk disease by magnetic resonance imaging. Sagittal view of a lumbar spine,
T2 weighted images. a Disk bulging at multiple levels, most prominent at L1
L2, L3
L4 and
-
-
L5
S1, and indenting the spinal canal (arrows). VB indicates vertebral body; Asterisk indicates
intervertebral disk. b Disk herniation at the T12
-
T12-L1 level, with migration of disk material posterior
to the T12 vertebral body (arrowhead). Disk bulging (arrow) is present at L1
-
L2 and L2
L3 as
-
-
well
