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154 Cards in this Set
- Front
- Back
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What is the cause of nodular cortical or subcortical enhancement
2 |
hematogenous dissemination of mets neoplasm and emboli
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What is the DDx open ring enhancement
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MS
Tumefactive demyelination Fluid Secreting neoplasm |
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What are 3 causes of subependymal enhancement
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Primary CNS lymphoma
Primary glial tumors Infectious ependymitis |
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What is another name for a pleomorphic adenoma
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parotid benign mixed tumor
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What percent of parotid tumors are benign
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80%
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What is the MC tumor of the parotid gland
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a pleomorphic adenoma
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What are general characteristics of a pleomorphic adenoma
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well defined, smooth capsule
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What is the density of a pleomorphic adenoma on CT
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CT: similar in density to muscle
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What are the signal characteristics of a pleomorphic adenoma on MR
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MR: hypo T1, bright T2
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What percent of pleomorphic adenomas undergo malignant degeneration
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20% malignant degeneration (CA ex pleomorphic adenoma)
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What is the 2nd MC tumor of the parotid gland
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warthins gland tumor
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Are warthins glands sometimes multicentric
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yes, 20% of the time
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Do warthins gland tumors sometimes have a cystic component
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yes 30% of the time
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What part of the parotid gland to warthins glands most commonly occur
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the tail
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What demographic will tend to get warthins gland tumor
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elderly men
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What are the MR findings of a warthins gland tumor
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heterogeneous appearing, hypo T1, variable T2
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What nuclear study can be used to examine a warthins gland tumor
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pertechnetate
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What are the findings on a Tcm 99 pertectnetate study if a pt has a warthins gland tumor
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it will be hot
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What are the less common parotid gland tumors
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oncocytoma (looks like BMT), hemangioma (peds, very bright T2, intense enhancement +/- phleboliths), neurofibroma, schwannoma (CN 5 or 7), lipoma
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What is the appearance of a warthins gland tumor on MR
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heterogeneous
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What is a common finding of a malignant tumor of the parotid gland
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a facial palsy
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Are parotid tumors commonly dark on T2 weighted images
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yes, but not always
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What is the most common malignant parotid tumor
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Mucoepidermoid CA is MC malignant parotid tumor
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Can you t rely on border or shape to distinguish malignant from benign in parotid
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no
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What occurs for a every parotid tumor
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biopsy
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What are other less common tumors of the parotid glands
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`adenoid cystic CA, squamous cell CA, adenocarcinoma, undifferentiated, basal cell and squamous cell CA from skin or EAC, acinic cell (rare), lymphoma
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Do basal an squamous cell sometimes cause parotid cancer
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yes
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Does adenoid cystic cancer occur in the parotid gland
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yes
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Can lymphoma cause tumors in the parotid
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yes, lots of lymph nodes
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What are the causes of inflammatory/infectious changes in the parotid glands
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sialolith (stone)
viral (esp mumps) bacterial autoimmune (Sjogren and Sarcoid) |
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When are lymphoepithelial cyst seen in the parotid gland
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AIDS
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Are lymphoepithelial cyst usualy bilateral
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yes
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What do lymphoepithelial cyst look like
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cystic warthins gland tumor
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What is an indication that a cyst may be a warthins gland tumor and not lymphoepithelial cyst
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the age of the patient. If you see cyst in the parotid glands and the patient is young you should be suspicious for an HIV infection
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What do the cyst of lymphoepithelial cyst look like
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cystic parts follow CSF density/intensity
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What is the ddx of cystic chang of the the parotid gland
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lymphoepithelial cysts, Warthin, Sjogren, sarcoid, mets, acinic CA
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Can acinar Ca, sjogrens and sarcoid cause cystic change of the parotid glands
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yes
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If there is a lot of swelling around the parotid gland what should you always look for
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a stone in stensons duct
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What do you see in the late stages of sjogrens (in the parotids)
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calcifications, enlargement, heterogeniety
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What is the ddx of a lacrimal gland lesion
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mixed benign tumor
lymphoma iodiopathic orbital disease (pseudotumor) adenoid cystic Ca sarcoidosis sjogrens dermoid and epidermoid |
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Is it easy to differentiate a dermoid from other pathology
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Can tell dermoid by fat/fluid level, otherwise cannot really distinguish lesions
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If there is bony destruction adjacent to a lesion what should be considered
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malignancy
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What do the lacrimal glands look like on imaging in sarcoid
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T2- with increased signal intensity.
T1 with contrast-, prominent enhancement of the lacrimal glands |
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Are the lacrimal glands enlarged in sarcoidosis
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yes
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What is the ddx of a lacrimal gland tumor
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Benign mixed tumor
Lymphoma Idiopathic orbital inflammatory disease (pseudotumor) Adenoid cystic CA Sarcoidosis Sjogren Dermoid epidermoid |
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What are the clinical findings in a patient with tuberous sclerosis
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seizure
mental retardation facial angiofibroma |
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What is another name for a facial angiofibroma seen in tuberous sclerosis
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adenoma sebaceum
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What 2 renal findings are associated with tuberous sclerosis
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angiomyolipoma
renal cyst |
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What cardiac anomaly is associated with tuberous sclerosis
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rhabdomyoma (50-60%)
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Renal: angiomyolipoma and cysts 40-80%
Cardiac: rhabdomyomas 50-65%; majority involute Lung: lymphangioleiomyomatosis/fibrosis Solid organs: adenomas, leiomyomas Skin: ash-leaf spots (majority) including scalp/hair; facial angiofibromas; shagreen patches 20-35% post pubertal Extremities: subungual fibromas 15-20%; cystic bone lesions; undulating periosteal new bone formation; bone islands Ocular: giant drusen (astrocytic hamartoma) (50%) Dental pitting of permanent teeth in most adults with TS |
Renal: angiomyolipoma and cysts 40-80%
Cardiac: rhabdomyomas 50-65%; majority involute Lung: lymphangioleiomyomatosis/fibrosis Solid organs: adenomas, leiomyomas Skin: ash-leaf spots (majority) including scalp/hair; facial angiofibromas; shagreen patches 20-35% post pubertal Extremities: subungual fibromas 15-20%; cystic bone lesions; undulating periosteal new bone formation; bone islands Ocular: giant drusen (astrocytic hamartoma) (50%) Dental pitting of permanent teeth in most adults with TS |
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What are 4 CNS findings in patients with TSC
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Periventricular subependymal nodules
cortical and subcortical tubers WM lesions subependymal giant cell astrocytomas |
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Do subependymal nodules and cortical tubers tend to calcify
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yes, 80% of subependymal tubers are Ca+, 50% of parenchymal tubers Ca+
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What is more common subependymal nodule or tubers
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subependymal nodules
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Do subependymal giant cell astrocytomas enhance
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yes
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What are the MR signal characteristics of tubers
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Tubers low T1, high T2
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What are the hallmarks of SGCA
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Hallmarks are growth and enhancement
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What is a common complication of SGCA
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Often causes obstructive hydrocephalus b/c located at/near foramen of Monro
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Where do esthesioneuroblastomas arise from
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Arises from the olfactory nerve
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What are the clinical findings in a patient with esthesioneuroblastomas
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Causes nasal obstruction, epistaxis, decreased sense of smell
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Do Esthesioneuroblastoma commonly have calcifications
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yes
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What is the signal characteristic of a esthesioneuroblastoma on MR
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intermediate to low T2, tend to cross cribriform plate into anterior cranial fossa
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Do SCC of the nasal cavity tend to calcify
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no, helps to differentiate from esthesioneuroblastoma
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What is the ddx of a nasal cavity tumor
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squamous cell CA (not Ca+), lymphoma, SNUC, inverted papilloma, adenoCA, chondrosarcoma of nasal septum, mets
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What is a common cause of a cerebellar infarct
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vetebral dissectionq
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What is the typical demographic to get vetebral dissections
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older men
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What are the clinical findings of a vertebral artery dissection
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HA, vertigo, dysarthria, N/V, nystagmus, dysmetria, gait disturbance
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What are indirect finds of a infarct of the cerebellum on MR
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Check 4th ventricle for symmetry to find subtle mass effect, and check temporal horns for hydrocephalus
Can cause upward or downward transtentorial herniation |
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What causes 10-25% of infarcts in the younger population
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carotid or vetebral artery dissections
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What are the common etiologies for carotid or vetebral artery dissections
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spontaneous
HTN major trauma trivial trauma (chiropractic = classic) iatrogenic |
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What are the MRA and angiogram findings in a dissection
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MR: high T1 from intramural hemorrhage, irregular or narrow lumen.
Angiogram: string sign (segmental tapering), sometimes 2 lumens, aneurysmal dilatation, vascular occlusion, intimal flap, retention/poor washout from dissection |
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What causes the string sign on an angiogram
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the string sign is caused by thrombus in the false lumen compressing the true lumen
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What is the ddx of a CPA tumor
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vestibular schwannoma
meningioma ependymoma neuroepithelial cyst aneurysm |
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What causes 80% of CPA tumors
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vestibular schwannoma
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Do vestibular schwannomas have arachnoid cyst occasionally
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yes
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What is a clue that a CPA tumor is a vestibular schwannoma
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if it expands the IAC
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What are 2 neuroepithelial cyst
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Epidermoid (bright DWI), arachnoid cyst (mirrors CSF)
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Are epidermoids typically bright on DWI
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yes
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What must always be excluded when dealing with a CPA tumor
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an aneurysm (pica or vetebral)
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What is the 2nd MC CPA tumor
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meningioma
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What should be done if you see a intramedullary cystic lesion
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If see cystic intramedullary cord lesion, give contrast to differentiate syrinx from cystic tumor or syrinx secondary to tumor
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Are syrinx commonly associated with intramedullary tumors
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yes, sometimes
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What is the ddx of an intramedullary tumor that may have an associated syrinx
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astrocytoma, ependymoma, hemangioblastoma
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Where do myxopapillary ependymomas occur
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in the lumbar region
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What are the findings of a ependymoma in the spinal cord
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Circumscribed, enhancing cord mass with hemorrhage
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Are spinal cord ependymomas associated with central canal widening
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yes, 20% of the time
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Do ependymomas of the spinal cord often have cyst and hemorrhage
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yes, commonly
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What is the cause of the focal hypointense signal around an ependymoma
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hemosiderin
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Do ependymomas of the spinal cord often have homogenous enhancement
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yes, well defined homogenous enhancement in 50%
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What are the findings of an astrocytoma of the spinal cord
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Usually large, involving full diameter of cord
Enhances Often infiltrating and unresectable Cannot reliably distinguish from ependymoma |
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What is one subtle difference between an ependymoma and astrocytoma of the spinal cord
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ependymomas tend to be posterior while astrocytomas tend to involve the entire spinal cord
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What portion of the spinal canal do ependymomas tend to involve
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the lumbar, and posteriorly
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Where do hemangioblastomas tend to occur
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cervical and thoracic
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Do most hemangioblastomas have a solid and cystic component
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yes
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Hemangioblastomas have solid components enhance, may have hemorrhage
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yes
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What vascular characteristic is unique to hemangioblastomas (in differentiating spinal cord tumors)
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Flow voids in tumor or prominent posterior draining veins
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1/3 of pts with spinal cord hemangioblastoms have VHL
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yes
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What is a disc herniation
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Localized (< 50% of disk circumference) displacement of disk material beyond confines of disk space...annulous pulposa
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What is a disc protrusion
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Herniated disk with broad-base at parent disk
Greatest dimension of disk herniation in any plane ≤ distance between edges of the base in same plane |
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What is a disc extruction
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Herniated disk with narrow or no base at parent disk
Greatest dimension of disk herniation in any plane > distance between edges of the base in same plane |
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Disc herniation classification. A: Normal disc anatomy demonstrating nucleus pulposus (NP) and annular margin (AM). B: Disc protrusion, with NP penetrating asymmetrically through annular fibers but confined within the AM. C: Disc extrusion with NP extending beyond the AM. D: Disc sequestration, with nuclear fragment separated from extruded disc.
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Disc herniation classification. A: Normal disc anatomy demonstrating nucleus pulposus (NP) and annular margin (AM). B: Disc protrusion, with NP penetrating asymmetrically through annular fibers but confined within the AM. C: Disc extrusion with NP extending beyond the AM. D: Disc sequestration, with nuclear fragment separated from extruded disc.
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What is the ddx of a intramedullary spinal tumur ( within the spinal cord below the pia matter)
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ependymoma
astrocytoma hemangioblastoma syrinx intramedullary AVM |
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intramedullary
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intramedullary
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Intradural extramedullary (subarachnoid or subdural space)
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Intradural extramedullary (subarachnoid or subdural space)
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extradural
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extradural
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What is the ddx of an intradural extramedullary tumor
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meningioma
schwannoma neurofibroma hemangiopericytoma |
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What is the ddx of a extradural lesion
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herniated disc
synovial cyst osteophyte rheumatoid pannus mets abscess hematoma epidural lipomatosis |
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Where are trigeminal schwannomas usually located
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Can be based in middle cranial fossa, Gasserian ganglion, or posterior fossa
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What are the MRI characteristics of a schwannoma
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iso T1, hyper T2, with avid enhancement
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What is the ddx of lesions that may erode the petrous apex
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cholesterol granuloma
epidermoid mets meningioma chordoma chondrosarcoma schwannoma |
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what should be suspected if there is enlargement of the foramen ovale, rotundum or SOF
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swchwannoma
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What is the appearance of a meningioma in the region of the cavernous sinus
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Follows lateral margin of the cavernous sinus
May extend posterior along tentorium in “dove’s tail” appearance |
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What encases the ICA rather than displace it
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meningiomas tend to encase the ICA rather than displace it, opposite of a schwannoma
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What is the ddx of a parasellar or cavernous sinus lesion
8 |
aneurysm
meningioma trigeminal schwannoma pituitary adenoma extending lateral perineural spread from mets or H&N lesion chondrosarcoma from sellar bone |
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What are the findings of thyroid orbitopathology
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CT: enlarged extraocular muscles (“I’M SLow”), spares musculotendinous insertions
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What is a potential complication of the muscular hypertrophy in thyroid disease
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possible compression of the optic nerve by enlarged muscles
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Besides muscular hypertrophy what other orbital findings are there thyroid disease
3 |
increased orbital fat
proptosis Lacrimal glands may be involved |
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Is a orbital pseudotumor usually bilateral or unilateral
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unilateral
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What is the radiographic appearance of an orbital psuedotumor
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will involve the muscular insertion, orbital fat and appear as muscular thickening, a mass or stranding
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Is orbital thyroid disease usually unilateral
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no symmetric
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What diseases is pseudotumor associated with
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Wegener
PAN retroperitoneal fibrosis sclerosing cholangitis Reidel thyroiditis mediastinal fibrosis |
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What is the T2 signal characteristic of pseudotumor
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MR: low T2
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What are 3 ddx of pseudotumor
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lymphoma
wegners sarcoid |
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Is a classic appearance of a pilocytic juvenile astrocytoma a cyst with a mural nodule
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yes
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What is the most common brain tumor diagnosed in children
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pilocytic astrocytoma
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What is the radiographic appearance of a pilocytic astrocytoma
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Usually cyst with enhancing mural nodule, off midline
Occasionally solid, then similar to medulloblastoma, ependymoma |
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What is a potential complication of pilocystic astrocytoma
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hydrocephalus
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What is the ddx of a tumor with a cyst and nodule
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JPA (anywhere), pleomorphic xanthoastrocytoma and ganglioglioma (temporal lobe), hemangioblastoma (posterior fossa)
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Where do gangliogliomas tend to occur
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in the temporal lobe
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What type of tumor is the cause of the majority of brainstem gliomas
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astrocytome (grade 2)
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Where is the MC location for a brainstem glioma
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the pons
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What are the radiographic findings in a patient with a brainstem glioma
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expansile enlargement of brainstem, ventral pons extends beyond anterior margin of basilar artery, exophytic growth into cisterns (20%)
Cranial nerve palsies pyramidal tract |
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Are brainstem gliomas usually situated anteriorly or posteriorly
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anterior
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What is the prognosis and treatment of a brainstem glioma
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20-30% 5y survival
chemotherapy and radiation |
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How often is there exophytic growth of a brainstem glioma with out
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20%
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What is the ddx of a brainstem lesion
8 |
brainstem glioma
tuberculoma lymphoma rhombic encephalitis demyelination diseasse infarction resolving hematoma vascular malformation |
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Where should the conus be located in an infant
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In infant, normal conus should be above L2-3
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What are the findings in an infant with a tethered cord
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conus ends below L2 inferior endplate
tethered by thickened filum +/- fibrolipoma, terminal lipoma |
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What are the US findings of a tethered cord
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nerve roots do not float freely, filum may be short and thick (> 2 mm)
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Is there often a fibrolipoma or terminal lipoma in a patient with a tethered cord
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yes
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What should be investigated closely in pts with a tethered cord
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The spine becuase there may be an occult spinal dysraphism such as lipomyelomeningocele
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What are the types of a carotid cavernous fistula
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direct and indirect
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What is the cause of an indirect carotid cavernous fistual
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dural arteriovenous fistual of cavernous sinus, typically supplied by numerous ECA +/- cavernous ICA branches
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What does a dural AVF look like
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What is the MCC of indirect carotid cavernous fistuala (dural avf)
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idiopathic
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What is the cause of a direct CC fistula
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: high-flow, single hole fistula between ICA and cavernous sinus
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What are the causes of direct CC fistula
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trauma (MC)
ruptured aneurysm iatrogenic spontaneous |
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What disease will predispose a pt to a direct CC
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ehlers danlos
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What is the ddx of enlarged extraocular muscles
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pseudotumor, Graves, CCF
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What is the ddx of a dilated superior opthalmic vein
5 |
CCF
cavernous sinus thrombosis, venous varix Graves normal variant |
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What may be seein in a patient with a CC AVF during angiogram
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can show communication and may show filling of superior +/- inferior ophthalmic veins, petrosal sinus to IJ, and cortical veins
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vein of galen malformation
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Vein of galen malformation
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What vessels are involved in a vein of galen malformation
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VGAM is misnomer; malformation actually involves the median prosencephalic vein (MPV) of Markowski which becomes "aneurysmal"/dilated
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What is the MC extracardiac cause of highoutput failure in a newborn
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VGAM
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