Neurorad Flashcards
Neuro
Disk protrusion terminology
Bulge: Broad-based disk bulge. Usually bulging annulus fibrosus. Protrusion: Focal disk bulge. Usually herniated nucleus pulposus.
Intervertebral disk high intensity zone (HIZ)
High T2 signal of annulus indicating annular tear.
Disk free fragment mimickers
Conjoined root: Normal variant of two roots exiting thecal sac together. Same density of thecal sac.
Tarlov cyst: Normal variant of dilated nerve root sleeve. Same density of thecal sac.
Lateral Disks
May cause nerve root impingement causing symptoms of a superior level. Nerve root has already exited central canal.
Common causes of Central Canal Stenosis
Facet joint degenerative change (most common). Lligamentum flavum hypertrophy
Most common cause of neuroforaminal stenosis
Facet joint degenerative change with bony encroachment.
Lateral recess
Lumbar spine bony canals where nerve roots lie after exiting thecal sac and before entering neuroforamen. Hypertrophy of superior articular facet is most common cause of encroachment.
Spondylolysis identified on axial images
Break in bony ring of the lamina (pars interarticularis) at the mid vertebral body level.
Spondylolisthesis occurs from either
Bilateral spondylolysis.
Facet joint degenerative change.
Distinguishes postop scar from disk material
Scar tissue enhances. Disk material has only minimal peripheral enhancement.
Differentiates disk infection fromdegenerative disk disease at MR
Type 2 degenerative disk disease: Low T1 disk and high T2 parallel endplate bands. Disk space infection: High T2 disk.
Myelopathy neurologic signs
Ataxia. Bowel and bladder incontinence. Babinski sign.
Common causes of myelopathy
Extramedullary: Epidural mass cord compression. Cervical spine stenosis. Intramedullary: Tumor. Inflammation, Arteriovenous malformation (AVM). Spinal dural arteriovenous fistula (SPAVF).
Definition of Intramedullary spinal canal lesion
Usually confined to spinal cord. May be exophytic.
Definition of extramedullary spinal canal lesion
Outside of spinal cord. May be intradural or extradural.
Intradural intramedullary lesions
Ependymoma. Astrocytoma. Hemangioblastoma. Lipoma/(Epi)dermoid. Syringohydromyelia. Intramedullary AVM. Met/abscess (rare).
Intradural extramedullary lesions (includes subarachnoid space)
Meningioma. Schwannoma/neurinoma. Neurofibroma. Hemangiopericytoma. Lipoma/(Epi)dermoid. Arachnoid cyst/adhesion. Drop/leptomeningeal metastasis. Veins (extramedullary AVM).
Extradural extramedullary lesions
Degenerative: Herniated disc. Synovial cyst. Osteophyte. Rheumatoid pannus. Nondegenerative: Metastasis. Abscess. Hematoma. Primary tumor expansion or invasion. Epidural lipomatosis
Atlantoaxial instability and rheumatoid arthritis
Inflammatory changes (pannus) destroy transverse ligament of C1. Dens may slide posteriorly and intermittently compress cord causing myelomalacia. 5% of RA patients frank atlantoaxial instability.
Vertebral body and disc infection findings
Adjacent vertebral bodies and disc usually involved. Destruction greatest at endplates. Posterior elements usually spared. Low T1 and high T2 marrow signal with normal diffusion. If pyogenic disk enhances, granulation tissue extends above and below affected vertebrae.
Vertebral body neoplasm findings
Isolated or noncontiguous involvement. Pedicles typically affected. Low T1 and high T2 signal with restricted diffusion. Disk typically spared (except prostate cancer). Enhancement may obscure metastases within fatty marrow.
Vertebral body osteoporosis findings
Several vertebral bodies with height loss. Anterior weding with posterior elements spared. Normal T1 and T2 unless fracture. Disk spared.
TB of the spine, or Pott disease
Causes slow collapse of one or more vertebral bodies. Gibbus deformity, acute kyphosis. Infection spreads underneath longitudinal ligaments. Can lead to cord compression. May spare disks.
Most common neoplasm of the spine
Metastases
