Neuroradiology Flashcards
DDx cystic sellar lesions
- Rathke cleft cyst
- Arachnoid cyst
- Craniopharyngioma
- Epidermoid cyst
- Dermoid cyst
DDx pineal gland tumors
- Pineal cyst
- Germ cell tumors (germinoma, non-germinoma: choriocarcinoma, embryonal cell carcinoma, teratoma); engulfs calcium
- Pineoblastoma (exploded calcium)
- Pineocytoma
- Metastases
What is Tolosa-Hunt Syndrome?
Tolosa-Hunt Syndrome is an idiopathic granulomatous inflammation of the cavernous sinus hat typically presents with painful ophthalmoplegia with involvement of one or multiple cranial nerves located in the cavernous sinus and superior orbital fissure.
DDx for a unilateral cavernous sinus mass
- Schwannoma
- Meningioma
- Lymphoma
- SCC via perineural spread
- Sarcoidosis
- Tolosa-Hunt Syndrome
- Thrombophlebitis
- Fungal infections
- Aneurysm
What disease is associated with a cotton wool appearance of the skull?
Paget’s disease
DDx for jugular foramen tumors
- Glomus jugulare (salt and pepper; erosive bone changes)
- Schwannoma (can be cystic; bone remodeling without destruction)
- Meningioma
- Rare (chondrosarcoma, hemangiopericytoma, plasmacytoma)
DDx calcified brain metastases
- Breast cancer
- GI mucinous adenocarcinoma
- Papillary thyroid
- Osteosarcoma
- Ovarian
What are typical findings of intracranial hypotension?
Classic triad: (rarely see all signs)
- Diffuse dural thickening/enhancement
- Downward displacement of brain through incisura (“slumping” midbrain)
- Subdural hygromas/hematomas
(4. distended dural sinuses)
What are findings of normal pressure hydrocephalus?
- Lateral ventricles enlarge +/- aqueductal flow void
- Transependymal flow
- Enlarged basal cisterns, sylvian fissures; normal sulci
- CC bowed upward or CC thinning
- crowding of the gyri at the vertex
What are typical findings of increased intracranial pressure?
- Partial empty sella
- Dilation/tortuosity of optic nerve sheath
- Flattening of posterior sclera
- increased fluid around optic nerves
- MRV to exclude dural sinus thrombosis/stenosis
What features make up the Mondini malformation of the cochlea?
Triad of:
1) 1.5 turns of the cochlea
2) enlarged vestibule with normal SC canals
3) enlarged vestibular aqueduct
What is Pendred syndrome?
Bilateral SN hearing loss and goitre
Most common cause of syndromic hearing loss
What is Michel aplasia?
aka complete labyrinthine aplasia, is a congenital abnormality of the inner ear and is characterized by bilateral absence of differentiated inner ear structures with resultant anacusis
Absence of the semi-circular ducts is frequently associated with what congenital syndrome?
CHARGE syndrome (coloboma, heart defects, atresia [choanal], retardation, genital hypoplasia, ear abnormalities/deafness)
What is the normal size of the vestibular aqueduct?
Should not exceed 1.5 mm or the width of the posterior semicircular canal
What is the classic triad of Gradenigo syndrome?
1) petrous apicitis
2) CN 6 palsy
3) Trigeminal neuralgia or retro-oribtal pain
What are the 3 most common expansile masses at the petrous apex?
- Cholesterol granuloma
- Cholesteatoma
- Mucocele
What is a cholesterol granuloma?
Foreign body giant cell reaction to cholesterol deposits occurring in obstructed fluid-filled air cells developing a recurrent cycle of hemorrhage and granulation.
What is a cholesteatoma?
Cholesteatoma is histologically equivalent to an epidermoid cyst and is composed of desquamated keratinizing stratified squamous epithelium forming a mass. Usually present with conductive hearing loss.
What are the most common tumors at the CP angle (4)?
“AMEN”
- Acoustic schwannoma (~80%)
- Meningioma (~10%)
- Ependymoma (~5%)
- Neuroepithelial cyst (epidermoid/arachnoid) (~5%)
What are typical MR findings of metachromatic leukodystrophy?
- symmetric confluent T2 hyperintensity periventricular and deep WM
- Tigroid pattern: sparing of perivenular WM
- Early: spares subcortical U-fibers
- Later: involves U-fibers and atrophy may be present
What are imaging features of Chiari I malformation?
- Peg-like cerebellar tonsils > 5 mm below foramen magnum
- may see assoc syringohydromyelia
- may see elongation of the fourth ventricle
What is Stenson’s duct?
Parotid gland duct
What is Wharton’s duct?
Submandibular gland duct
What is the major duct of the sublingual gland called?
Bartholin duct
What is Plummer disease?
toxic adenoma within multi nodular goiter or just toxic MNG
Which brain metastases have increased T1 signal before contrast administration?
-melanoma, kidney, lung, choriocarcinoma and bowel (due to mucin)
What brain tumors may be low on T2-WI?
- CNS lymphoma
- PNET
- mucinous-adeno metastases (GI, lung, breast, GU)
- melanoma met
- germinoma
- GBM can be
- Calcificied masses (e.g. meningioma)
- Blood (old hemorrhage in tumor or vascular malformation)
What are possible causes of PRES?
Many aetiologies with HTN
- Acute/subacute systemic HTN
- Pre-eclampsia, eclampsia
- Drug toxicity (e.g. cisplatin, cyclosporine)
- Uremic encephalopathies
- Thrombotic microangiopathies (DIC, TTP)
What is the pattern of inheritance for NF 2? Which chromosome?
- AD
- Chromosome 22
What does MISME in NF 2 stand for?
Multiple inherited schwannomas, meningiomas, and ependymomas
What is the pattern of inheritance for NF 1? Which chromosome?
- AD; but 50% new mutations
- chromosome 17q11.2
Which one of the following is MOST likely to cause a jugular foramen mass? A. Paraganglioma B. Astrocytoma C. Schwannoma D. Meningioma
A. Paraganglioma is the most common tumor of the jugular foramen.
What structures are located within the cavernous sinus?
- cavernous ICA
- CN 3, 4, V1, V2 (laterally)
- CN 6 (medially)
- venous plexus
Perineural spread of neoplasm involves which cranial nerves most commonly?
CN V and VII
DDx for ring-enhancing cerebral lesions
“MAGIC DR”
- metastases
- abscess
- GBM
- infarct (subacute phase)
- contusion
- demyelinating disease
- radiation necrosis or resolving hematoma
What is the Chamberlain line? What is its significance?
The Chamberlain line extends from the posterior margin of the hard palate to the opisthion (posterior margin of the foramen magnum). It is abnormal if the tip of the odontoid projects >5 mm above this line.
What syndromes may involve the craniovertebral junction and cause atlantoaxial instability?
- Klippel-Feil syndrome
- Down syndrome
- Connective tissue disorders, such as Ehlers-Danlos
- Inflammatory conditions such as RA
- Achondroplasia
- Mucopolysaccharidoses
- Osteogenesis imperfecta
What are the common locations for cysticercosis?
1) Hematogenous spread produces lesions at the GW junction
2) intraventricular lesions
3) subarachnoid space lesions (racemose type) are the third most common site
When does acute disseminated encephalomyelitis (ADEM) occur?
1 to 3 weeks after nonspecific viral illness (may be subclinical) or vaccination
What are typical clinical findings of CJD?
Rapid progression of dementia, myoclonus, and mutism
What are the MR findings of CJD?
-symmetric high signal in the basal ganglia (better seen on DWI), no enhancement, bilateral symmetrical involvement of the thalamic pulvinars is typical, and the occipital cortex may also be involved. CT usually only shows atrophy.
What is Rasmussen encephalitis?
It is a chronic focal encephalitis that is progressive and unilateral. Etiology is uncertain, but likely viral then autoimmune.
Late disease shows unilateral cortical atrophy with ex-vacuo ventricular dilatation. T2 hyperintense in the affected hemisphere. May have restriction. No significant post-contrast enhancement.
What is the most common leukodystrophy?
Metachromatic leukodystrophy (1:100,000 newborns)
DDx for dural ectasia
- NF 1
- Ankylosing spondylitis
- Marfan syndrome
- Ehler Danlos syndrome
- Osteogenesis imperfecta
- Post traumatic
DDx solitary parotid gland mass
- Pleomorphic adenoma (benign mixed tumor; most common; 10-25% risk of malignant transformation)
- Warthin tumor (second MC; cigarette smoking; may have cysts)
- Lymphoma
- Mets
- Mucoepidermoid/ACC
- Acinic cell carcinoma
- First branchial cleft cyst
- Oncocytoma
- Neurogenic tumor
- Lymphangioma
DDx nasal cavity mass
- Nasal polyp
- Juvenile angiofibroma (very vascular)
- Inverting papilloma (cerebriform pattern; 5-15% risk of degen into SCC)
- SCC (usually make smokers)
- Olfactory neuroblastoma (esthesioneuroblastoma)
- Encephelocele (rarely)
DDx bilateral parotid gland lesions
- benign lymphoepithelial cysts (HIV)
- Sjogren syndrome
- Warthin tumor
- lymphoma
- metastatic lymphadenopathy
- sarcoidosis
- Oncocytoma
DDx suprasellar mass in adults
“SATCH MOE”
- Suprasellar adenoma
- Aneurysm
- Teratoma
- Craniopharyngioma (arise from Rathe’s cleft; age 40s, typically calcified and cystic)
- Histiocytosis; Hypothalamic glioma
- Meningioma; Metastases
- Optic nerve glioma
- Eosinophilic granuloma; Epidermoid cyst
How can you differentiate between pineal germinoma and pineoblastoma?
- Germinoma tends to have “central engulfed calcium”.
- Pineoblastoma tends to “blast” the calcium outwards.
- Germinomas show higher ADC values than pineal cell tumors.
What disease is associated with salt and pepper skull?
Hyperparathyroidism
DDx posterior fossa tumors in children
“BEAM”
- Brainstem glioma (tectal, pontine, diffuse intrinsic pontine glioma); causes mass effect on floor of the 4th ventricle
- Ependymoma
- Astrocytoma (pilocytic)
- Medulloblastoma
What structures go through Foramen Ovale?
“OVALE”
- Otic ganglion (situated directly under the foramen)
- V3 cranial nerve (mandibular nerve)
- Accessory meningeal artery
- Lesser petrosal nerve (of CN IX)
- Emissary veins (from the cavernous sinus to the pterygoid plexus)
What runs through Foramen Spinosum?
- Middle meningeal artery
- Posterior trunk of the middle meningeal vein
What runs through Foramen Rotundum?
Rotunda connect the middle cranial fossa and the pterygopalatine fossa.
-CN V2 (maxillary nerve) passes through and exits the skull
What are the branches of the external carotid artery?
“Some Anatomists Like Freaking Out Poor Medical Students”
From inferior to superior: -Superior thyroid a (arises from anterior aspect) -Ascending pharyngeal a (medial deep aspect) -Lingual a (ant. aspect) -Facial a (ant. aspect) -Occipital a (post. aspect) -Posterior auricular a (post. aspect) Terminal branches: -Maxillary a -Superficial temporal a
Where is Meckel’s cave? What is located there?
- Situated posterolateral to the cavernous sinus on either side of the sphenoid bone
- Trigeminal ganglion (aka Gasserian or semilunar ganglion) lies within Meckel’s cave
DDx of intradural, intramedullary lesions of the spine
- Ependymoma
- Astrocytoma
- Hemangioblastoma
- Lipoma/Epidermoid
- Syringohydromyelia
- Intramedullary AVM
- Rare site: metastasis, abscess
DDx of intradural, extramedullary lesions of the spine
- Meningioma
- Schwannoma/neurinoma
- Neurofibroma
- Hemangiopericytoma
- Lipoma/Epidermoid
- Arachnoid cyst, adhesion
- Drop or leptomeningeal metastasis
- Veins (extramedullary AVM)
DDx of extradural lesions of the spine
Degenerative: -Herniated disc, diskal cyst -Synovial cyst -Osteophyte -Rheumatoid pannus Non-degenerative: -Metastasis -Epidural Abscess -Epidural hematoma -Primary tumor expansion or invasion -Epidural lipomatosis
What is the most common tumor involving the filum terminale?
Myxopapillary ependymoma (>90% of tumors in this region)
DDx for neoplasms of the caudal equina
- Myxopapillary ependymoma
- Schwannoma
- Paraganglioma
- Intradural metastases
- Hemangioblastoma
- Meningioma
- Astrocytoma
- Spinal PNET
- Ganglioglioma
- Lipoma of the filum terminale
- Dermoid/Epidermoid
Medulloblastomas are associated with which syndromes?
- Gorlin syndrome
- Turcot syndrome
- Li-Fraumeni
- Cowden
- Gardner
What are the entrances/exits of the pterygopalatine fossa?
Posteriorly:
-Foramen rotundum: middle cranial fossa
-Vidian canal: middle cranial fossa, foramen lacerum
-palatovaginal canal (pharyngeal): nasal cavity/nasopharynx
Anteriorly: inferior orbital fissure: orbit
Medially: sphenopalatine foramen: nasal cavity
Laterally: pterygomaxillary fissure: infratemporal fossa
Inferiorly:
-Greater palatine foramen
-Lesser palatine foramen
Which is the most common odontoid fracture?
Type II
Which odontoid fractures are stable or unstable?
Type 1: fracture of the upper part of the odontoid peg; usually considered stable
Type 2: fracture at the base of the odontoid; risk of non-union; unstable
Type 3: through the odontoid and into the lateral masses of C2; relatively stable if not excessively displaced
What is Powers ratio?
Powers ratio defines a normal relationship between the base of the skull and the atlas. Length of a line drawn from the basin to the spinolaminar line of C1 divided by the length of a line drawn from the opisthion to the posterior margin of the anterior arch of C1. If the ratio is
What does MELAS stand for?
Myopathy
Encephalopathy
Lactic Acidosis
Strokes