Spine Flashcards
What is a ventral cord herniation. What are MRI findings
Rare cause of focal myelopathy due to herniation of the thoracic cord through a dural defect, between T2-T8. Anterior dural defect allowing the subarachnoid space to communicate with the extradural space.
Often it is idiopathic. Can be post traumatic or post surgical.
focal distortion and rotation of cord, no CSF between it and the ventral theca. Often bulges beyond confines of theca with T2 signal abnormality in cord (myelopathy)
PEDIATRIC
how to differentiation lipomyelocele from lipomyelomeningocele
Both are closed spinal dysraphisms with a lipoma connected to the spinal cord at the level of a placode, the placode-lipoma interface.
lipomyelocele = placode-lipoma interface lies within the spinal canal
lipomyelomeningocele = placode-lipoma interface lies outside the spinal canal
What is a placode
In cases of spina bifida, represents flattened and wide spinal cord termination
What is typical MRI appearance of spinal cord infarction?
Most common in the anterior spinal artery territory (anterior 2/3rds of the cord) because of pair posterior spinal arteries and pial collaterals.
T2 hyperintensity in the central aspect of the spinal cord. No enhancement. Mass effect if present is mild. DWI +ve.
What are the imaging features of a tethered cord?
Associated abnormalities?
Low conus medullaris (below L2 inferior endplate)
thickened filum terminale (>2mm)
Associated abnormalities: filum terminale lipoma syringohydromyelia myelomalacia diastematomalyelia spinal dysraphism scoliosis VACTERL association
What is VACTERL association?
Vertebral anomalies Anorectal anomalies (anal atresia) Cardiac anomalies, cleft lip Tracheoesophageal fistula Esophageal atresia Renal anomalies, radial ray anomalies Limb anomalies
What syndrome are hemangioblastomas associated with?
von Hippel-Lindau syndrome (25-30% of HBs)
Routine screening of brain and spine is recommended starting at age 10 for patients with VHL.
What is spinal hemangioblastoma and what are the imaging findings?
Third most common intramedullary spinal cord tumour (behind astrocytoma and ependydoma). 2-6% of cases.
Who Grade 1.
Thoracic (50%) or cervical (40%) most common.
Most lesions are intramedullary with an exophytic component.
MRI:
Diffuse cord expansion with associated cyst/syrinx.
T1 iso, T2 hyper, surrounding flow voids
Vivid enhancement of tumour nodule.
What are the most common sites of extraspinal metastatic spread of spinal ependymoma? (3)
Lungs, retroperitoneum, lymph nodes
What is the typical MRI appearance of spinal cord ependymomas?
WHO grade?
most commonly in the cervical spine. on average involves ~3.6 vertebral segments
T1 hypo-iso, T2 iso-hyper
20-33% “cap sign”, extreme T2hypo (hemosiderin) at tumor poles
cord edema and expansion
polar cysts common (80%), tumor cysts rare
syringohydromyelia variable
hemorrhage is common
well defined enhancement
Almost all spinal cord ependymomas are WHO grade 1 or 2
Most common neoplasm of the filum terminale/conus medullaris?
myxopapillary ependymoma (83%)
can occasionally occur in the EXTRADURAL space
Most common spinal cord tumor in adults?
Ependymoma
second most common is astrocytoma (which is most common intramedullary tumor in children)
typical MRI appearance of spinal cord astrocytoma?
Most common location: Thoracic cord (67%), followed by cervical cord (49%)
poorly defined margins (infiltrate surrounding tissue, as opposed to ependymomas which displace)
usually eccentric within the cord (57%)
T1 hypo-iso, T2 hyper
on average involves 7 vertebral segments
cysts are common (polar and tumoral [20%])
enhancement +ve
no cap sign
leptomeningeal spread in 60% of GBMs
WHO grade 1-4
What is the mean age of presentation and gender predilection of spinal gangliogliomas?
19 years
no gender predilection
Typical MRI appearance of spinal cord gangliogliomas?
RARE in spinal cord (most are supratentorial)
arise from cervical spine mostly(48%) commonly eccentric Mixed T1 intensity, T2hyper tumoral cysts common (46%) calcification uncommon bone remodeling common (93%) patchy or pial surface enhancement common
WHO grade 1-2 (10% malignant transformation)
What syndrome is associated with multiple hemangioblastomas?
von Hippel-Lindau syndrome
30% of patients with a spinal hemangioblastoma have von Hippel-Lindau syndrome. Cerebellar and retinal findings usually precede spinal cord manifestations
What is a spinal hemangioblastoma?
Nonglial highly vascular slow growing neoplasm.
Most commonly in the thoracic (50%) and cervical (40%) cord.
patients younger than 40
75% intra-medullary, can be intradural or extradural.
syrinx is common
Typical MRI appearance of spinal hemangioblastoma?
Dilated tortuous feeding arteries and draining pial veins
highly vascular with intensely enhancing tumor nodule
diffuse cord expansion
variable T1 signal (50% are iso)
T2 hyper with focal flow voids
syringohydromyelia and cyst formation very common
surrounding edema
cap sign can be seen
What is tabes dorsalis?
It is a form of tertiary neurosyphilis in which there is demyelination of the posterior columns of the spinal cord.
Radiologically, it can manifest as neuropathic arthropathy, usually involving hip, knee or spine.
On MRI, there can be longitudinal T2hyper in the dorsal columns of the spinal cord
TRUE OR FALSE
The absence of enhancement does not exclude an intramedullary neoplasm in the presence of cord expansion
TRUE
In the spinal cord, what is a polar/satellite cyst?
They are cysts located at the poles of the solid portion of a spinal cord tumor. They usually represent reactive dilatation of the central canal (syringomyelia).
Present in 60% of intramedullary spinal tumors. NOT PART OF THE TUMOR.
TRUE OR FALSE
In resection of spinal cord masses, polar cysts need to be resected as well
False
polar cysts are reactive dilatation of the central canal and will resorb post resection of the tumor.
What is the difference in enhancement between polar and tumoral cysts?
Polar cysts do not enhance, whereas tumoral cysts are contained within the tumor and enhance peripherally.
Which of these tumors shows tumoral cysts more commonly:
Ependymoma vs astrocytoma
Astrocytoma
Why is it important to precisely locate the enhancing portion of the tumoral cysts in a spinal cord tumor?
Because they need to be resected with the tumor.
What extra-spinal location can myxopapillary ependymoma be found in?
It can be found in the subcutaneous tissue of the sacrococcygeal region, usually without any connection with the spinal canal.
Why do ependymomas cause symmetric cord expansion?
Because they are believed to arise from ependymal cells of the central canal within the spinal cord.
What is the location of myxopapillary ependymoma?
It is virtually always located along the filum terminale with occasional extension to the conus medullaris.
TRUE OR FALSE
Spinal astrocytomas contain areas of hemorrhage more often than spinal ependymomas
FALSE
Hemorrhage in ependymoma is common, but uncommon in astrocytoma
What is the difference in the enhancement pattern of a spinal astrocytoma vs ependymoma?
Astrocytoma: Patchy irregular enhancement
Ependymoma: Focal, intense homogeneous
What is the most common extramedullary-intradural tumor?
Nerve sheath tumor (neurofibroma, schwannoma) (70-75%)
How do you localize an intradural (extramedullary) spinal mass as opposed to extra-dural?
Identify a subarachnoid cap: widening of the subarachnoid space around the lesion.
Most common extradural spinal metastases in adults?
Breast
Lung
Prostate
Most common extradural spinal metastases in children?
Ewing sarcoma
Neuroblastoma
What is a myelomeningocele?
A myelomeningocele is herniation of portions of the spinal cord or nerve roots containe in a sac, through a posterior spinal column defect (spina bifida)
