Imaging Anatomy There are 33 spinal vertebrae, which comprise 2 components: A cylindrical ventral bone mass, which is the vertebral body , and the dorsal arch . 7 cervical, 12 thoracic, 5 lumbar bodies 5 fused elements form the sacrum…
KEY FACTS Terminology Optic nerve sheath meningioma Also known as perioptic meningioma Benign, slow-growing tumor of optic nerve sheath Distinct entity from intracranial (spheno-orbital) meningioma that extends through orbital apex into orbit Imaging NECT “Tram-track” Ca++ on either side of…
KEY FACTS Terminology Optic pathway glioma (OPG) Primary neuroglial tumor of optic pathway 3 broad clinical subtypes Childhood syndromic [neurofibromatosis type 1 (NF1)], childhood sporadic, adult Imaging Fusiform optic nerve (ON) mass with variable posterior pathway involvement MR is preferred…
KEY FACTS Terminology Nonspecific orbital inflammation, not due to any known etiology or systemic illness Imaging Best imaging tool: Contrast-enhanced MR with fat suppression Poorly marginated mass-like enhancing soft tissue involving any area of orbit Categorized by area(s) of involvement…
KEY FACTS Terminology Synonyms: Graves ophthalmopathy, thyroid orbitopathy Autoimmune orbital inflammatory condition associated with thyroid dysfunction Imaging CT For uncomplicated disease and surgical planning Nonuniform, symmetric, or asymmetric extraocular muscle involvement Enlargement of muscle bellies, sparing tendinous insertions “I'M SLO”…
KEY FACTS Imaging Focal or segmental T2 hyperintensity of optic nerve Nerve normal in size or minimally enlarged Central or diffuse nerve enhancement ± peripheral sheath enhancement Top Differential Diagnoses Neuromyelitis optica Ischemic optic neuropathy Infectious optic neuritis (ON) Idiopathic…
Imaging Approach & Indications General Approach Imaging of the orbit encompasses 2 clinically distinct areas of ophthalmology: (1) The eye or globe and (2) the bony orbit, soft tissues, and periorbita. Lesions in these 2 areas result in specific clinical…
KEY FACTS Imaging Enhancing lesion(s) with skull/meningeal destruction/infiltration Skull, dura, leptomeninges, arachnoid/subarachnoid, pia, and subgaleal Many manifestations: Smooth thickening, nodularity, loculation, lobulation, fungating masses Top Differential Diagnoses Skull metastases: Surgical defect (burr hole, craniectomy), myeloma Dural metastases: Epidural/subdural hematoma, meningioma…
KEY FACTS Terminology Clonal B-lymphocyte neoplasm of terminally differentiated plasma cells Solitary = plasmacytoma – Brain/CNS is extramedullary plasmacytoma Multifocal = multiple myeloma (MM) Imaging Intracranial MM rare (1% of MM) Can occur as solitary (primary) plasmacytoma or manifestation of…
KEY FACTS Terminology Benign intraosseous skull lesion with predominantly vascular and some avascular components Imaging Best clue Sharply marginated expansile skull lesion Frontal, temporal, parietal bone in decreasing order Most often solitary, but multiple in 15% Best imaging tool: Bone…