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…
KEY FACTS Terminology Typical (benign) meningioma = WHO grade I Atypical meningioma (AM) = WHO grade II Malignant meningioma (MM) = WHO grade III Imaging CT triad of MM: Extracranial mass, osteolysis, intracranial tumor MR Dural-based locally invasive lesion with…
KEY FACTS Imaging Intradural extramedullary mass Thoracic (80%) > cervical (16%) > lumbar (4%) Typically round or ovoid (en globe) En plaque variety pancaked or flat along dura Broad-based dural attachment Strong homogeneous enhancement Prominent “dural tail” less common than…
KEY FACTS Terminology Trichilemmal cyst (TC) is preferred term Sebaceous cyst commonly used but incorrect Variant = proliferating trichilemmal tumor Keratin-containing cyst Lined by stratified squamous epithelium Pathology looks like root sheath of hair follicle Imaging General features Most within…
KEY FACTS Terminology Multisystem inflammatory disease characterized by noncaseating epithelioid-cell granulomas Imaging Solitary or multifocal CNS mass(es) ± abnormal CXR CXR abnormal in > 90% with neurosarcoid (NS) Wide spectrum of MR manifestations Dura-arachnoid thickening (diffuse or focal)) May coat…