Category Neurology

Normal Fatty Marrow Variants

KEY FACTS Terminology Red marrow: Hematopoietic marrow Yellow marrow: Fatty marrow Imaging Yellow marrow often distributed around central perforating vein Yellow marrow adjacent to endplates in degenerative disc disease After bone marrow transplantation: Fat centrally located in vertebral body, red…

Epidural Lipomatosis

KEY FACTS Terminology Excessive accumulation of intraspinal fat causing cord compression and neurologic deficits Imaging Thoracic spine: 58-61% T6-T8, dorsal to spinal cord Epidural fat ≥ 7 mm thick Lumbar spine: 39-42% L4-L5, surrounding thecal sac Y-shaped configuration to lumbar…

Perineural Root Sleeve Cyst

KEY FACTS Terminology Dilatation of arachnoid and dura of spinal posterior nerve root sheath, containing nerve fibers a.k.a. Tarlov cyst Imaging Occur anywhere along spine Most common in lower lumbar spine and sacrum S2 and S3 nerve roots most commonly…

CSF Flow Artifact

KEY FACTS Terminology Cerebrospinal fluid (CSF) flow-related phenomenon due to time of flight (TOF) effects and turbulent flow Imaging Location: Intrathecal, subarachnoid space Most prominent in cervical and thoracic spine Low or high signal intensity Ill-defined margins Top Differential Diagnoses…

Anterior Lumbar Radiculopathy

KEY FACTS Terminology Uncommon complication following intrathecal chemotherapy Transient or permanent paraplegia Initially described following intrathecal methotrexate (MTX) in pediatric acute lymphoblastic leukemia patients Imaging Smooth linear enhancement of conus pia, anterior cauda equina nerve roots Unenhanced T1W, T2W images…

Postirradiation Vertebral Marrow

KEY FACTS Terminology Transformation of cellular vertebral marrow into fatty marrow following therapeutic irradiation Imaging Sharp demarcation between irradiated and untreated marrow (margins of radiation port) Corresponds to site of irradiation and extent of radiation field Marrow signal intensity within…

Radiation Myelopathy

KEY FACTS Terminology Chronic progressive radiation myelitis Delayed radiation myelopathy Imaging Spindle-shaped cord swelling with irregular, focal rind of enhancement (early) Focal cord atrophy (late) Clinical signs may reflect longer segment of damage than demonstrated on MR Top Differential Diagnoses…

Spinal Cord Metastases

KEY FACTS Terminology Metastatic lesion from primary carcinoma in another organ (including brain) Imaging Focal, enhancing cord lesion(s) with extensive edema Typically small (< 1.5 cm) T1WI: Enlarged cord T2WI/PD/STIR: Focal high signal represents diffuse edema Rarely syrinx T1WI C+:…

Myxopapillary Ependymoma

KEY FACTS Terminology Slow-growing glioma arising from ependymal cells of conus, filum terminale, cauda equina Imaging Usually spans 2-4 vertebral segments May fill entire lumbosacral thecal sac Ovoid, lobular, sausage-shaped CT/radiographs ± osseous canal expansion, thinned pedicles, vertebral scalloping May…

Classic Ependymoma

KEY FACTS Terminology Neoplasm arising from ependyma lining spinal cord central canal Imaging Circumscribed, enhancing hemorrhagic cord mass with surrounding edema Associated cysts common Cervical > thoracic > conus T1WI: Isointense or slightly hypointense to spinal cord T2WI: Hyperintense relative…