Spine imaging Flashcards
What are the intramedullary lesion causes?
astrocytoma ependymoma hemangioblastoma metastasis demyelinating lesion inflammatory process infection
vascular lesion syrinx
traumatic cord injury
What are the intradural extramedullary (within the thecal sac outside the cord) lesion causes?
meningioma schwannoma neurofibroma myxopapillary
ependymoma paraganglioma spinal dysraphism epidermoid/dermoid neurenteric cyst arachnoid cyst/web cord herniation arachnoiditis Guillain-Barré
CIDP
What are the extradural lesion causes?
extradural metastasis vertebral neoplasm hemangioma epidural lipomatosis degenerative disease nondegenerative
hypertrophic disease discitis/osteomyelitis epidural abscess
crystal deposition disease spondyloarthropathies Paget disease
spinal fracture epidural hematoma epidural extension of
tumor
Describe what MRI is shown?
Where is the location of the lesion?
What is dx and its associated diseases?
Sagittal T2-weighted (left image as CSF is bright) and T1-weighted post-contrast (right image) MRI shows an intramedullary mass in the thoracic spine (yellow arrows) which expands the spinal cord and causes cord signal abnormality from the mid thoracic spine down. A focus of hypointensity on the T2-weighted image at the inferior
aspect of the lesion may represent hemorrhagic material (red arrow). On the post-contrast image, the mass demonstrates wispy enhancement inferiorly (blue arrow). This was an astrocytoma.
Astrocytomas are most common intramedullary tumor (deep to pia mater) in children and second most common in adults.
They are associated with neurofibromatosis type 1 (along with neurofibromas)
Most spinal astrocytomas are low grade. Spinal glioblastoma (WHO grade 4) is rare.
What is the occurence of ependymoma in adults and children?
What disease association?
Ependymomas are the most common intramedullary tumor in adults and 2nd most common in children.
Associated with neurofibromatosis type 2 (along with schwannomas and meningiomas)
Most are low grade (WHO grade II).
Well defined margins and intense, heterogenous enhancement. Cystic components are seen in up to half.
Where does spinal haemangioblastomas occur?
What disease is it associated with?
Appearance?
Spinal haemangioblastomas are uncommon benign tumors in adults.
Associated with von Hippel Lindau syndrome, which should be suspected when there are multiple lesions in the neuraxis (most commonly involving spinal cord, retina, and cerebellum)
Well defined margins and intense, homogenous enhacenement. They are typically small (involving only 1 vertebral level)
What are short segment and long segment causes of saggital cord involvement (non neoplastic)?
Short segment: MS, transverse myelitis (uncommon), hemorrhage, acute/subacute infection, sarcoidosis
Long segment: transverse myelitis, NMO, MS (uncommon), cord infarction, vascular malformation, chronic infection, sarcoidosis, anti MOG associated myelitis
What is observed?
It may mimic a spinal tumor but what is the distinguishing feature?
Sagittal STIR (left image) and axial T2 (right images) MRI show multiple T2 hyperintense lesions (arrows) within the visualized spinal cord, predominantly in the central cord, in this patient with known MS.
Typical spinal MS lesions appear as focal hyperintensity on T2-weighted images (visible in two planes) that are short (one or two vertebral segments), peripherally located, and occupying the minority of the cord in cross-section.
Distinguishable from a neoplasm by the absence of cord expansion, multifocality involving the brain and spine, as well as CSF oligoclonal bands.
Who is affected by ADEM (acute disseminated encephalomyelitis)?
- ADEM is an uncommon demyelinating disorder with an acute monophasic course that typically follows a viral infection or vaccination. It usually occurs in children.
- Spinal cord involvement occurs in a minority of cases, characterized by multifocal or large confluent, T2 hyperintense, intramedullary lesions with cord swelling and variable enhancement.
What is seen and describe each mode of MRI
Spinal cord abscess: Sagittal T2 (left image), T1 pre-contrast (middle image), and T1 post-contrast (right image) MRI demonstrate an elongated area of abnormal intramedullary signal in the lower cervical spinal cord with heterogeneous high T2 and low T1 signal (yellow arrows), and peripheral enhancement after gadolinium administration (red arrows). There is associated cord edema extending superiorly and inferiorly, and cord expansion.
What supplies the anterior and posterior portion of spine?
What connects the blood supply of anterior and posterior spine?
1 anterior spinal artery –> anterior sulcal artery
2 posterior spinal artery
Connected via the segmental artery (lateral) linked by the anterior and posterior radicular artery).
What is the sign of the image on the left?
At what level does this commonly occur and why?
What are it’s risk factors?
Axial T2-weighted MRI (left image) shows symmetric hyperintense foci involving the ventral horns of the intramedullary gray matter (“owl eye appearance”).
Corresponding axial DWI (top image) shows bright spots, suggestive of restricted diffusion.
Most common spinal infarction is in the upper thoracic or thoracolumbar spine due to the artery of Adamkiewicz which comes from a branch of the intercostal or lumbar artery on level T9-12.
- Spinal cord infarction clinically presents with loss of bowel and bladder control, loss of perineal sensation, and impairment in both motor and sensory function of the legs.
- Risk factors for spinal cord infarction include aortic surgery, aortic aneurysm, arteritis, sickle cell anemia, vascular malformation, and disc herniation.
- Imaging of spinal cord infarction shows hyperintensity of the affected cord regions on T2- weighted images. The cord may be enlarged and typically shows restricted diffusion.
Describe what MRI and where is the lesion
What is dx and where is the lesion normally located?
Intradural-extramedullary mass: Sagittal T2-weighted (left image) and axial T1-weighted post-contrast (right image) MRI shows an intradural thoracic mass (arrows). The mass is distinct from the spinal cord and displaces the cord posteriorly. The axial image shows severe posterior compression of the cord (arrow) by the avidly enhancing mass. This was a meningioma. Usually, however, thoracic meningiomas are posterior to the spinal cord.
Where do meningiomas occur in the spine?
What is its associated disease?
And imaging signs?
Typical meningiomas are benign intradural extramedullary neoplasms.
Meningiomas are associated with neurofibromatosis type 2 (NF2)
Imaging classically shows an intensely enhancing mass with a dural tail. Calcification is uncommon. The thoracic region is most commonly involved.
Where do benign nerve sheath tumors (schwannoma, neurofibroma) occur?
What associated disease?
Mostly benign intradural extramedullary tumors from nerve roots 15% are both intradural and extradural, 15% are completely extradural. Intramedullary is rare.
Multiple lesions in younger patients are seen in neurofibromatosis type 1 (neurofibroma) and type 2 (schwannoma). Schwannomatosis is another genetic disorder with multiple schwannomas.
Spinal schwannnomas most commonly involve the lumbar region and the 2nd most common tumor in the cauda equina region. Spinal neurofibromas most comonly involve the cervical region.
Describe what MRI and what is seen?
What is dx and where is location?
Myxopapillary ependymoma: Sagittal T2 (left image), T1 (middle image), and post-contrast T1-weighted (right image) MRI demonstrate a heterogeneously T2 hyperintense, lobulated mass (red arrows) containing regions of hypointensity on the T2-weighted image. The mass is located at the conus medullaris and avidly enhances. There is also enhancing leptomeningeal dissemination along the surface of the more proximal cord (yellow arrows) and along the cauda equina nerve roots (blue arrow).
Myxopapillary ependymomas are the most common tumor of the cauda equina region, arising from ependymal glia within the conus medullaris and filum terminale. They are a benign variant of ependymoma.
The tumor is characterized by slow growth, classically presenting when larger and sausage shaped, causing vertebral scalloping and spinal canal enlargement. It frequently hemorrhages, resulting in peripheral haemosidern deposits as hypointensity on T2 weighted images and blooming on GRE.
What 2 main forms of spinal dysraphism are there?
Open spinal dysraphism: most common is myelomeningocele
Closed spinal dysraphism includes split cord malformations, caudal regression syndrome, persistent ventriculus terminalis, dorsal dermal sinus, neurenteric cyst, spinal lipoma variants including lipomyelomeningocele, meningocele (herniation of CSF filled dural sac) and myelocystocele (herniation of syrinx outside spinal canal)
What is myelomeningocele and where does it commonly occur?
What disease association?
- Neural tube defect in which pleural placode and meninges protrude through defective vertebral posterior elements and are exposed above the skin surface
- The lumbosacral region is most commonly involved. Patients have neurologic deficits involving the bowel, bladder and lower extremities.
- Nearly always associated with Chiari II malformation. Hydrocephalus is present in most cases.
Describe what mode of MRI and what is dx?
Diastematomyelia: Coronal T2-weighted MRI (left image) shows CSF between the two hemicords (arrows) and a thoracolumbar dextroscoliosis. Axial T2-weighted MRI (right image) shows two hemicords (arrows) within a single CSF space.
Describe what mode MRI and what is seen?
How to distinguish from blood vessel?
Filar lipoma/ fatty filum
Sagittal T1-weighted MRI shows a hyperintense lesion in the filum (arrow), representing fat in the filum terminale.
Of note, a potential pitfall is to mistake an enhancing vessel as a fatty filum. A fatty filum will be apparent on the noncontrast sequences as well.
What mode of MRI and what is seen?
Sagittal T2 (left image)
and T1 post-contrast
(middle image) MRI show
a large heterogeneously T2 hyperintense, nonenhancing intradural extramedullary mass (yellow arrows) which displaces the conus and
cauda equina roots. The
mass demonstrates restricted diffusion (right image, red arrow). These findings are consistent with an epidermoid.
More commonly acquired than congenital. Spinal epidermoids are caused by implantation of skin elements isn the subarachnoid space during spinal puncture.
Epidermoid cyst are commonly hypointense on T1W MRI and hyperintense on T2W MRI
What mode of MRI and what is seen?
Arachnoid cyst:
Sagittal and axial T2 MRI images demonstrate anterior displacement of the thoracic spinal cord by an intradural extramedullary lesion with CSF signal intensity. The margins of this lesion are hard to define (yellow arrows). This is thought to represent an arachnoid cyst.
Arachnoid cyst: CSF collection, usually intradural but occasionally extradural.
What mode of MRI and what is seen?
Arachnoid web:
Sagittal and axial T2 MRI (left and middle images) demonstrate dorsal indentation on the thoracic spinal cord (scalpel sign, yellow arrow) with associated void flows within the posterior aspect of the thecal sac (red arrow), but without a clear lesion seen. Axial CISS image (right image) shows linear hypointense signal within the dorsal thecal sac at this level (blue arrows), suggesting the presence of a dorsal arachnoid web.
Arachnoid web: abnormal arachnoid membrane in the subarachnoid space. Should be suspected in the presence of a spinal cord deformity or obstructed CSF flow without defined walls
Spinal arachnoid cysts and webs are most commonly located dorsal to the thoracic cord.
What mode of MRI and what is seen?
Sagittal T1 and T2 MRI (left and middle images) show focal anterior deformity of the thoracic cord, due to anterior herniation of the cord through a ventral dural defect (yellow arrow). There is associated mild intramedullary T2 signal abnormality (red arrows) and prominence of the dorsal subarachnoid space at this level (axial T2, above).
Cord herniation is a cause of myelopathy when the spinal cord plugs and protrudes through a dural defect, usually ventrally involving the thoracic cord.
What areas of disc herniations are there and how does this affect the nerve that will be compressed?
Lesions in the central (including right or left central for lesions just parasagittal to midline) or subarticular (lateral recess) locations may compress the descending/traversing nerve root, while foraminal or extra-foraminal lesions may compress the exiting nerve root.
Sequestered disc:
Sagittal T2-weighted MRI demonstrates an extradural mass (arrow) posterior to the inferior endplate of a mid-lumbar vertebral body.
Despite having different signal intensity from the parent disc, this was a sequestered disc fragment.
What are the axial MRI features of spinal stenosis?
How to assess neural foraminal stenosis severity?
Describe what is seen and what scan is best done for dx?
- The neural foramina are paired openings at each intervertebral spinal level through which the spinal nerve roots pass. They are located at the lateral aspects of the vertebral canal, and are bounded by the intervertebral disc-endplate complexes anteriorly, the articular processes and facet joints posteriorly, and the pedicles inferiorly and superiorly. Thus,
a combination of discovertebral degeneration and facet arthropathy (and the overlying ligamentum flavum) may contribute to neural foraminal stenosis.
Exit nerve should be surrounded by epidural fat with keyhole morphology.
Axial T1W MRI is best
Axial T2W MRI
Facet arthropathy is important to identify and accurately grade, as the facet joints can contribute to spinal, foraminal, or lateral recess stenosis.
facet effusions are associated with spinal instability and if a decompression is performed in the setting of instability, an instrumented fusion is typically the optimal treatment.
Active facet arthropathy can be treated by interventional pain procedures including intra- articular steroid injection, median branch block, and radiofrequency ablation.
What are the different spine infections?
Ossification of the posterior longitudinal ligament (OPLL):
The right image shows OPLL along the upper to mid cervical spine (arrows). Note partially visualized post-surgical changes of cervical laminectomies and posterior instrumented fusion, which were performed to decompress the spinal stenosis caused by OPLL.
- Ossification of the posterior longitudinal ligament (OPLL) is characterized by bone formation along the posterior longitudinal ligament.
- OPLL most frequently involves the cervical spine, followed by the thoracic spine.
- OPLL contributes to spinal canal stenosis and may compress the anterior aspect of the cord.
What is the 3 column concept for spinal trauma?
What must be evaluated in every lateral cervical spine radiograph?
What are significant values to be wary of?
What are the 4 primary osseous contours?
What is the cut off for spinal stenosis diameter in spinal canal?
Spinal canal <13mm is spinal stenosis
What are the different fractures affecting C1 and C2?
Flexion teardrop fracture: Presentation radiograph demonstrates an anterior teardrop fragment (yellow arrow) and retropulsion of C5 into the spinal canal. MRI shows traumatic disc extrusion with caudal migration (red arrow) and spinal stenosis. There is disruption of the posterior ligamentous complex with tear of the ligamentum flavum (blue arrow) and interspinous ligament (green arrow). Note focal fluid signal in the cord at the C7 level (white arrow), which is thought to most likely represent a syrinx. The patient was treated with C5–C6 anterior decompression and fusion.
Flexion teardrop fracture is most severe cervical spine injury potentially compatible with life.
Flexion teardrop fracture can cause anterior cord syndrome due to compression of the pyramidal tracts and anterior spinothalamic tracts. Presents as complete paralysis and loss of pain and temp sensation. The dorsal column usually remains intact, preserving touch and vibration sense.
