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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_6012_Библиотеки_им_академика_М_И_Перельмана.pdf
Chapter 13 Spine Imaging 213
SECTION
II
A
FIG. 13.16 Lumbar canal stenosis. (A) Sagittal and (B) axial T2-weighted magnetic resonance images show
severe central canal stenosis at L3–L4 and L4–L5 with marked compression of the thecal sac owing to anterior
bulge of the anulus brosus and facet hypertrophic degenerative change. There are small bilateral facet
eusions (arrows).
B
spondylolisthesis are bilateral defects in the pars interarticularis (isthmic spondylolisthesis) and facet disease (degenerative spondylolisthesis). e degenerative variety is the most
common in older adults.
Because of its ability to obtain direct sagittal images free of
overlapping structures and patient rotation, MRI is an accurate
method of diagnosing spondylolisthesis. MRI is nearly always
performed with the patient supine, however. In that position,
a vertebra with subluxation can be normally aligned. A more
accurate method of detecting listhesis is by weight-bearing
lateral lumbar radiographs. e detection of spondylolysis
(pars interarticularis defect without ventral slippage) by MRI
can be problematic, and it is generally agreed that plain lms
and CT are more reliable for its diagnosis. Because MRI is
being increasingly used as the rst and only imaging modality
in evaluating patients with low back pain and radicular symptoms, many cases of spondylolysis are imaged without the
benet of correlative plain lms or CT studies.
166
Using MRI,
sagittal T1-weighted images are best for showing the pars
interarticularis owing to their higher signal-to-noise ratio, the
depiction of the pars marrow as hyperintense, and the minimal
obliquity of the pars in this imaging plane (Fig. 13.18). If the
pars appears normal (i.e., contiguous normal marrow signal),
one can be certain that it is intact.
167
Additionally, myelopathic symptoms tend to occur when the
canal cross-sectional area is less than 60 mm2. e ratio of the
anteroposterior canal diameter to the vertebral body diameter
has been used to assess cervical stenosis. is Pavlov ratio
(sometimes referred to as the Torg ratio) is normal if it is 1 or
168
gre ater.
A ratio of 0.8 or less is considered abnormal. As a
ratio, however, it can be abnormal not only because of an
abnormally small canal diameter (small numerator), but also
because of an abnormally large vertebral body (large denominator). is ratio method also does not take into account the
size of the spinal cord itself. As an isolated tool, this method
is of historical interest only and is useless in evaluating cervical
spinal cord compression.
Takahashi and colleagues and others have described areas
of increased signal intensity on T2-weighted images within the
cervical cord owing to extradural compression, which variously reects myelomalacia, gliosis, and demyelination and
edema (Fig. 13.19).
169
Patients who show areas of abnormal
signal within the cord tend to have a worse clinical condition
than patients with normal cord signal intensity. ese abnormal signal changes can disappear or diminish aer surgery to
relieve the cord compression.
Postoperative Imaging
Cervical Radiculopathy and Myelopathy
Various studies have shown that canal size is reduced in
patients with cervical spondylotic myelopathy. e normal
diameter of the canal from C3 to C7 is approximately 17 mm
and can be decreased to 12 mm or less in cervical spondylotic
myelopathy. e size that is associated with myelopathy has
ranged, however, from less than 10 mm up to 14 mm.
Causes of early and delayed failure of surgery are listed in
Boxes 13.1 and 13.2. Caution must be used in interpretation
of CT, CT myelography, and MRI within the rst 6 weeks aer
surgery owing to the large amount of tissue disruption and
edema that may be present producing mass eect on the anterior thecal sac, even in the absence of any clinical symptoms.
MRI may be used in the immediate postoperative period for a
214 DIAGNOSIS
A
C
FIG. 13.17 Synovial cyst. (A) Sagittal and (B) axial T1-weighted magnetic resonance images show mass with
central low signal centered on the right anterior facet that eaces the right dorsal aspect of the thecal sac. (C)
Sagittal and (D) axial T2-weighted images show central high signal of uid consistent with synovial cyst.
BOX 13.1 Technical Causes of Early Spine Surgery Failure
Hematoma
Infection
Inadequate decompression of bony foraminal or central stenosis
Insucient removal of herniation
Neural trauma
Unrecognized free disc fragment
Wrong level surgery
B
D
BOX 13.2 Technical Causes of Delayed Recurrence of Low Back Pain
or Radiculopathy
Arachnoiditis
Epidural brosis
Facet arthropathy with foraminal stenosis
Instability
New or recurrent herniation
Pseudomeningocele
Central canal stenosis
Infection
more gross view of the thecal sac and epidural space, to exclude
signicant postoperative hemorrhage, pseudomeningocele, or
disc space infection at the laminectomy site. CT myelography
is also a direct way to dene a pseudomeningocele and to
image the spine when hardware is present (Fig. 13.20).
Small uid collections are commonly seen in the posterior
tissues aer laminectomy. e signal intensities can vary
depending on whether the collections are serous (follow CSF
signal intensity) or serosanguineous (increased signal on
T1-weighted images owing to hemoglobin breakdown products). e distinction between small postoperative uid col-
lections and infected collections cannot be made by MRI
morphology or signal intensity. Acute hemorrhage typically
shows isointense to increased signal in the epidural space on
T1-weighted images and should show diminished signal on
Chapter 13 Spine Imaging 215
gradient-echo or T2-weighted images. Very acute blood collections may be isointense, however, on T1-weighted and
T2-weighted images (Fig. 13.21).
Aside from the various options for instrumentation that are
available, dierent types of bone gra materials are available,
FIG. 13.18 Spondylolysis. Sagittal T1-weighted magnetic resonance image
shows disruption of cortical margin of pars interarticularis (arrow) at L5–S1
consistent with spondylolysis. There is severe foraminal stenosis at L5–S1.
some with ramications when imaging.
170
Bone morphogenic
protein (BMP) can produce imaging ndings that can be
misinterpreted as infection, including prevertebral so tissue
swelling and vertebral body endplate resorption, although
these ndings typically resolve by 6 months.
171-173
Epidural Fibrosis and Disc Herniations
e use of contrast medium–enhanced MRI in the evaluation
of scar versus disc has been examined by several authors, with
reported accuracy rates of 96% to 100% for distinguishing scar
from disc.
of the normal epidural fat with postoperative brotic tissue,
which is capable of binding the dura and nerve roots to the
surrounding structures anteriorly and posteriorly. Epidural
brosis is seen to enhance consistently immediately aer
injection of contrast material (Fig. 13.22). is enhancement
occurs regardless of the time since surgery. Disc material does
not enhance on the early postinjection images owing to its lack
of vascularity (Fig. 13.23). In cases with a mixture of scar and
disc material, scar enhances but the disc material does not
enhance on early postinjection images.
used in the evaluation of postoperative patients. Georgy et al.
examined 25 patients with recurrent pain aer lumbar disc
surgery with MRI to evaluate the usefulness of gadoliniumenhanced fat suppression imaging in patients with failed back
surgery. e addition of fat suppression to enhanced T1-weighted
images improved the visualization of enhancing scar in all
cases, helped distinguish scar from recurrent herniated disc,
and showed more clearly the relationship of scar to the nerve
174
Lumbar epidural brosis (scar) is a replacement
Selective fat suppression on T1-weighted images has been
175
SECTION
II
A
FIG. 13.19 Cervical spondylosis. (A) Sagittal T1- and (B) T2-weighted magnetic resonance images show solid
fusion at C6–C7 level with a small osteophyte. There is severe central stenosis of the disc and osteophyte
complex and posterior ligamentous hypertrophy at C4–C5, C5–C6, and T1–T2 levels. There is myelomalacia
within the cord seen as high signal intensity on the T2-weighted image at C4–C5 (arrow). (C) Axial gradientecho image at C4–C5 conrms severity of central stenosis owing to broad-based disc and osteophyte.
B
C
216 DIAGNOSIS
roots and thecal sac. Overall there are conicting data as to
whether epidural scar is associated or causative of symptoms
following back surgery. e presence of scar did not correlate
with symptoms in a study of 40 patients.
176
When epidural scar
is present in symptomatic patients undergoing reoperation,
it is associated with a poor outcome.
177
Others suggest that
psychosocial factors rather than the presence of epidural scar
correlate better with symptoms.
178
Stenosis
Bony stenosis has been implicated as a cause of failed back
surgery in 60% of cases. Various mechanisms can lead to
stenotic changes in the canal or foramina. eir signicance
may vary, and many of these stenoses are not symptomatic.
Examples of mechanisms are as follows:
1. Bony overgrowth aer facetectomy may compromise a
lateral recess.
2. Aer posterior fusion, there may be late overgrowth of
bone into the posterior or lateral canals.
3. Aer anterior fusion, bone may extend into the canal or
foramen.
4. e narrowing of the interspace aer discectomy may allow
sucient facet overriding to produce a decreased size of
the lateral recesses or foramina.
5. Postoperative spondylolisthesis can produce focal stenosis.
Arachnoiditis
FIG. 13.20 Pseudomeningocele. Axial computed tomographic scan after
myelography shows metal artifact from prior pedicle screw xation. There is
pooling of contrast medium around and dorsal to the hardware owing to a
large pseudomeningocele (arrows).
Spinal MRI can identify the various characteristics of lumbar
arachnoiditis, as can CT and myelography.
179-181
ese may be
classied into three categories or patterns, which can be
applied to MRI, CT, or myelography, although a mixture of
patterns can occur in any one patient.
182
A
FIG. 13.21 Recurrent herniation mimicking blood. This patient underwent multilevel laminectomy and L3–L4
discectomy 3 weeks before examination. (A) Sagittal T1-weighted magnetic resonance image shows vague
anterior epidural mass at L3 and extensive postoperative changes in dorsal epidural soft tissues. (B) Sagittal
T2-weighted image shows L3 epidural mass to be of low signal, with eacement of anterior thecal sac. (C) After
contrast administration, sagittal T1-weighted image shows slight peripheral enhancement. Dierential diagnosis
included acute blood (deoxyhemoglobin) and large recurrent herniation. Because of homogeneity of low signal
and contiguity with disc space at L3–L4, recurrent herniation was favored. A large herniation was found at
reoperation.
B
C
Chapter 13 Spine Imaging 217
SECTION
II
A
FIG. 13.22 Postoperative epidural scar. Axial T1-weighted magnetic resonance images (A) before and (B) after
contrast administration show diuse enhancement of tissue surrounding the right lateral aspect of the thecal
sac (large arrow) and exiting the right S1 root (small arrow).
A B
B
C
D E
FIG. 13.23 Recurrent herniation. (A) Sagittal T1-weighted magnetic resonance image shows large anterior
epidural mass extending dorsal to L4 body from L4–L5 disc space. The patient previously underwent L4
laminectomy and discectomy. (B) Sagittal T2-weighted image shows a large disc extrusion migrating superiorly
from the disc space level, reecting free fragment. (C) After contrast medium administration, sagittal
T1-weighted image shows typical peripheral enhancement of large herniation. Axial T1-weighted images (D)
before and (E) after contrast administration show peripheral enhancement of the disc component at mid-L4
level (arrow).
218 DIAGNOSIS
e rst pattern is central adhesion of the nerve roots
within the thecal sac into a central clump of so tissue signal.
Instead of showing their normal feathery pattern, the nerve
roots are clumped into one or more cords. is pattern is most
easily identied on axial CT myelography or T1-weighted
MRI. e second pattern is adhesion of the nerve roots to the
meninges, giving rise to an “empty thecal sac” sign. On MRI,
only the homogeneous signal of the CSF is present within the
thecal sac, and the nerve roots are peripherally attached to the
meninges. On CT myelography, only the high-attenuation
contrast agent within the thecal sac is visualized, without the
nerve roots. In the third pattern, which can be viewed as an
end stage of the inammatory response, the arachnoid
becomes an inammatory mass that lls the thecal sac. On
myelography, this type of arachnoiditis gives rise to a block,
with an irregular “candle dripping” appearance. MRI shows a
nonspecic so tissue mass, as does CT myelography.
Infection
Infection should be considered in the dierential diagnosis for
back pain even though it is an uncommon disorder (1% of all
cases of osteomyelitis). When infection is considered, accurate
imaging is a necessary prelude for microbiologic diagnosis or
surgical drainage. Because abnormalities that appear on plain
radiographs usually take days to weeks to become apparent,
radionuclide studies and MRI have been the primary imaging
modalities for diagnosis of vertebral osteomyelitis.
CT has played a minor diagnostic role in cases with bony
or so tissue components and is not considered a mainstay for
the diagnosis of disc space infection.
tive than either plain lms or CT for detecting vertebral
osteomyelitis, and it approaches or equals the sensitivity of
radionuclide studies (Figs. 13.24 and 13.25).
183,184
MRI is more sensi-
185,186
A
D
B
FIG. 13.24 Pyogenic disc space infection. (A) Sagittal T1-weighted
magnetic resonance image shows typical pattern of disc space infection
with low signal from adjacent L3 and L4 bodies and abnormal
morphology to the disc itself. There is kyphotic angulation at that level,
with increased anterior epidural soft tissue. (B) Sagittal T2-weighted
image shows abnormal increased signal from L3 and L4, with irregular
margins to the disc space. There is severe thecal sac compromise
(arrow). (C) Sagittal T1-weighted image after contrast administration
shows marked enhancement of vertebral bodies, disc space, and
epidural phlegmon. (D) Degree of thecal sac compromise (large arrow)
and diuse paravertebral extension of inammatory process (small
arrows) are shown on axial T1-weighted image.
C
Chapter 13 Spine Imaging 219
SECTION
II
A
E
B
FIG. 13.25 Early disc space infection. (A) Sagittal T1-weighted magnetic resonance image shows loss of disc
space height at L2–L3 through L4–L5 but no overt marrow signal abnormality. (B) Sagittal T2-weighted
image shows abnormal increased signal in L4–L5 disc space but no marrow signal abnormality. (C) Sagittal
T1-weighted image after contrast administration shows mild patchy L4–L5 disc enhancement and mild
endplate enhancement. Dierential diagnosis at this time is severe degenerative disc disease versus early
disc space infection. (D) Grossly abnormal signal involving L4 and L5 bodies with loss of disc margin was
visible 5 weeks later on T1-weighted image. (E) L4–L5 disc now shows more marked increased signal on
T2-weighted image.
C
D
It is imperative to obtain both T1- and T2-weighted images
in the sagittal plane for optimal sensitivity to detect disease.
e T1-weighted spin-echo image allows detection of the
increased water content or marrow uid seen with inammatory exudate or edema. Similar to most pathologic processes,
disc space infection or vertebral osteomyelitis results in
increased signal intensity on T2-weighted images. e diagnostic specicity of MRI is provided by the signal intensity
changes on T1- and T2-weighted images and by the anatomic
pattern of disease involvement and the appropriate clinical
situation.
On T2-weighted images, the normal intervertebral disc
usually shows increased signal intensity within its central
portion that is bisected by a thin horizontal line of decreased
signal, termed the intranuclear cle. Aer the age of 30 years,
the cle is almost a constant feature of normal intervertebral
discs. Disc space infections on MRI typically produce conuent
decreased signal intensity of the adjacent vertebral bodies and
the involved intervertebral disc space on T1-weighted images
compared with the normal vertebral body marrow. A poorly
dened endplate margin exists between the disc and adjacent
vertebral bodies. T2-weighted images show increased signal
intensity of the vertebral bodies adjacent to the involved disc
and an abnormal morphology and increased signal intensity
from the disc itself, with absence of the normal intranuclear
cle. ese MRI ndings are much more typical of pyogenic
than of tuberculous osteomyelitis.
187
In a comparative study
of patients with suspected vertebral osteomyelitis, MRI had a
220 DIAGNOSIS
sensitivity of 96%, a specicity of 92%, and an overall accuracy
of 94%.
185
Scintigraphy with 67Ga and
99m
Tc bone scintigraphy
had a sensitivity of 90%, specicity of 100%, and accuracy
of 94% when combined. In this study, MRI was as accurate
and sensitive as radionuclide scanning for the detection of
Dagirmanjian and colleagues
188
investigated the sensitivity
of MRI ndings for vertebral osteomyelitis. ey considered
the “classic” MRI changes of vertebral osteomyelitis to include
decreased signal of disc and adjacent vertebral bodies on
T1-weighted images, increased nonanatomic signal of the disc
on T2-weighted images, increased signal of the adjacent vertebral bodies on T2-weighted images, and enhancement of the
disc and adjacent vertebral bodies. ese investigators found
95% of disc space infection levels had typical T1-weighted
vertebral body changes, and 90% had increased nonanatomic
signal of the disc on T2-weighted images. Only 54% of the
abnormal levels showed increased signal of the vertebral
bodies on T2-weighted images, however. Although 84% of
patients showed the typical T1-weighted vertebral body and
T1- and T2-weighted disc changes, only 49% of cases showed
the typical T1- and T2-weighted vertebral body and disc ndings as originally described. T1-weighted vertebral body, disc,
and endplate changes and T2-weighted disc changes are the
most reliable ndings of disc space infection and vertebral
osteomyelitis. In the initial stages of vertebral osteomyelitis,
when the disc space is not yet involved, it may be dicult to
exclude neoplastic disease or compression fracture from the
dierential diagnosis using only MRI. Follow-up studies are
usually necessary to dene the nature of the lesion further.
Boden and colleagues
189
suggested that in the postoperative spine the triad of intervertebral disc space enhancement,
anular enhancement, and vertebral body enhancement leads
to the diagnosis of disc space infection, with the appropriate
laboratory ndings, such as an elevated sedimentation rate. A
group of normal postoperative patients, however, has anulus
enhancement (at the surgical site), intervertebral disc enhancement, and vertebral endplate enhancement without evidence
of disc space infection. In these cases, the intervertebral disc
enhancement is typically seen as thin bands paralleling the
adjacent endplates, and the vertebral body enhancement
is associated with type 1 degenerative endplate changes.
is pattern should be distinguished from the amorphous
enhancement seen within the intervertebral disc with disc
space infection.
Staphylococcus aureus is the organism most commonly
associated with vertebral osteomyelitis and epidural abscess,
accounting for approximately 60% of the cases (Fig. 13.26). S.
aureus is ubiquitous, tends to form abscesses, and can infect
compromised and normal hosts. Other gram-positive cocci
account for approximately 13% of cases, and gram-negative
organisms account for approximately 15%. Clinical acute
symptoms classically include back pain, fever, obtundation in
severe cases, and neurologic decits. Chronic cases may have
less pain and no elevated temperature. Rankin and Flothow
190
described the classic clinical course of epidural abscess in
four stages: spinal ache, root pain, weakness, and paralysis.
Acute deterioration from spinal epidural abscess remains
unpredictable, however. Patients may present with abrupt
paraplegia and anesthesia. e cause for this precipitous
course is unknown, but it is thought to be related to a vascular
mechanism (e.g., epidural thrombosis and thrombophlebitis,
venous infarction).
191,192
e primary diagnostic modality in the evaluation of epidural abscess is MRI. MRI is as sensitive as CT myelography
for diagnosing epidural infection, but it also allows the exclusion of other entities, such as herniation, syrinx, tumor, and
cord infarction.
193,194
MRI of epidural abscess shows a so
tissue mass in the epidural space with tapered edges and an
associated mass eect on the thecal sac and cord. e epidural
masses are usually isointense to the cord on T1-weighted
images and of increased signal on T2-weighted images. Post
and colleagues
195,196
recommended that in ambiguous cases
either CT myelography or contrast medium–enhanced MRI is
necessary for full elucidation of the abscess (Fig. 13.27).
e patterns of MRI contrast medium enhancement of
epidural abscess include (1) diuse and homogeneous, (2)
heterogeneous, and (3) thin peripheral. Post and colleagues
found that enhancement was a very useful adjunct for identifying the extent of a lesion when the plain MR image was
equivocal, for showing activity of an infection, and for directing needle biopsy and follow-up treatment. Successful therapy
should cause a progressive decrease in enhancement of the
paraspinal so tissues, disc, and vertebral bodies.
197
Intramedullary Lesions
Diagnostic considerations of pathology involving the intramedullary space include neoplasm, vascular malformation, syrinx,
granulomatous disease, inammation, or demyelination.
Radiographs without intrathecal contrast have no value for
nonexpansile cord pathology, with late ndings of cord neoplasm
only inferred by canal expansion or osseous destruction. MR
imaging can directly visualize the cord and can characterize
nonexpansile cord abnormalities.
e imaging ndings of spinal cord neoplasm most commonly include cord expansion, syrinx formation, and
enhancement. For low-grade nonenhancing neoplasms there
is typically cord expansion.
pansile T2 or STIR hyperintense spinal cord, distribution of
signal abnormalities, enhancement, blood degradation
byproducts, and its behavior over time (if available) are all
useful factors to consider when arriving at an appropriate
dierential diagnosis. Transverse myelitis tends to involve
longer segments of the cord as opposed to multiple sclerosis,
which tends to be patchy and involves the dorsal or lateral
aspects of the cord. Enhancement should typically resolve by
2 months when present with multiple sclerosis (Fig. 13.28).
Spinal cord infarct can involve the ventral gray matter centrally
within the spinal cord; subacute combined degeneration has
a more posterior distribution.
Neoplasms
e most common intramedullary neoplasms are gliomas,
principally astrocytomas and ependymomas. Ependymomas
201,202
When faced with a nonex-
200
196
198-200
Chapter 13 Spine Imaging 221
SECTION
II
AB
FIG. 13.26 Disc space infection with epidural abscess. (A) Sagittal
T1-weighted magnetic resonance image shows slight decreased
signal of L4 and L5 marrow adjacent to disc space and poor denition
of distal thecal sac. (B) Sagittal T2-weighted image shows abnormal
increased signal from L4–L5 disc space (large arrow) and linear low
signal dorsal to L4 and L5 bodies outlining anterior epidural abscess
(small arrows). (C) Sagittal T1-weighted image after contrast
administration better denes margins of epidural abscess (arrows) by
enhancing margin extending inferiorly toward S1 level. Slight
abnormal enhancement is present within the disc itself. (D) Axial
D
are cited as the most frequent intramedullary tumors in adults
(Fig. 13.29). Although ependymomas may involve any portion
of the cord, they most commonly involve the conus medullaris
and lum terminale and are the most common primary tumor
of the lower spinal cord. Patients with these tumors present in
the fourth to h decades of life, oen with back pain.
203,204
A
typical appearance is an intradural extramedullary mass
involving the lum terminale and cauda equina, although it
can appear as fusiform enlargement of the cord itself.
205
Cervical intramedullary tumors may be seen in patients with
neurobromatosis type 2 (Fig. 13.30). ese tumors typically
enhance and may have intratumoral cysts. e myxopapillary
subtype is particularly common in the lumbosacral region,
typically appearing as a large, intensely enhancing mass spanning several vertebral levels. In most cases, the tumors appear
as intradural extramedullary lesions because of their bulky
exophytic growth, which lls the spinal canal. Overall signal
intensities are nonspecic, but because of their highly vascular
T2-weighted image shows loculated abscess as foci of high signal,
displacing caudal thecal sac dorsally (arrow).
nature, ependymomas oen show areas of T2-weighted shortening secondary to the presence of hemosiderin and ferritin,
which is strongly suggestive of the diagnosis.
manifest as subarachnoid hemorrhage.
Intramedullary astrocytomas constitute 6% to 8% of primary
spine tumors, with a peak incidence in the third to fourth
decades of life. Astrocytomas produce focal enlargement and
occasionally exophytic growth involving the cord. Of these
tumors, 75% to 92% are relatively benign, such as grades 1 and
2. Imaging shows fusiform enlargement of the cord over
several segments, whereas T2-weighted MRI shows increased
signal intensity reecting tumor and edematous cord. Cysts
are oen associated with these intramedullary tumors. ese
cysts may be benign, syringomyelic type of cavities, or actual
cysts associated with the tumor.
Hemangioblastomas are unusual cord tumors and
typically manifest in the third to fourth decades of life. ey
are frequently multiple and seen in association with von
C
206
207
ey also may
222 DIAGNOSIS
A
C
B
FIG. 13.27 Tuberculosis. (A) Sagittal T1-weighted magnetic
resonance image shows large mass involving L5–S2 bodies
with epidural extension. L5–S1 disc space is normal. (B)
T2-weighted image shows mass as heterogeneous high
signal. (C) After contrast administration, T1-weighted image
better denes epidural abscess with peripheral enhancement
(arrows).
Hippel–Lindau disease.
208-213
ese lesions most oen manifest as dorsal intramedullary masses containing a nodule that
enhances, although these vary by the amount of cyst component and solid component. ere may be extensive widening
of the cord, showing increased signal intensity on T2-weighted
images related to cord edema and extending several segments
away from the nidus itself.
Occasionally, metastatic disease may manifest as an
intramedullary enhancing mass. Carcinoma of the lung and
breast is the most common, with melanoma, lymphoma,
and renal cell carcinoma also reported.
214,215
Spread of intracranial neoplasms such as ependymoma and glioma may also
seed the leptomeninges and produce direct involvement of
the cord.
216-218
Benign intramedullary tumors are uncommon, but cavern-
ous angiomas (cavernous malformations) can occur in the
cord with typical signal characteristics of speckled increased
and decreased signal on T1-weighted images and evidence of
hemosiderin deposition on T2-weighted images (Fig. 13.31).
Inammation
e various causes of inammatory myelopathies include
multiple sclerosis, postviral demyelinating disease, viral
infection, pyogenic infection, and granulomatous disease.
e archetypal inammatory lesion is multiple sclerosis (Fig.
13.32). e spinal cord is the site of much clinical involvement
in patients with multiple sclerosis; however, imaging of the
spinal cord has always been subordinate to brain imaging
in radiologic investigations of multiple sclerosis. Because
some of the clinical disease activity in multiple sclerosis is
related to the spinal cord, it is important to correlate cord
disease with clinical activity to gain further insights into the
nature of disability in these patients and to correlate objective