MCQ Flashcards
Guillan Barre
Surface thickening and contrast enhancement of the conus medullaris and nerve roots of the cauda equina.
Anterior nerve roots more commonly involved than posterior.
Contrast important as non-contrast almost normal
Lemierre syndrome
Thrombophlebitis of jugular veins in setting of oropharyngeal infection, and distant metastatic sepsis
Calcific tendinitis longus colli
Retropharyngeal fluid without rim enhancement
C1-2 level amorphous calcification
Treat with non steroidals
Enhancement would suggest abscess or tumour
WCC and ESR may be raised
May cause fever
Jaw cysts
Ameloblastoma - soap-bubble lesion (Septated - most multicystic))
Dentigerous / follicular cyst - surround crown
Radicular cyst / periapical cyst - infection
KCOT - unilocular cyst, may mimic dentigerous cyst
DNET
T2 bubbly - gelatinous
Wedge shape may mimic infarct. Multinodular. Well circumscribed.
May show minimal enhancement
Minimal mass effect - may scallop inner skull
30% calcify
Associated with cortical dysplasia (up to 80%)
WHO 1
Temporal epilepsy
Cortical or deep grey matter (most commonly temporal)
Pilocytic astrocytoma
1st 2 decades
Cyst with enhancing nodule
May calcify
Cerebellum and optic pathway
Ganglioglioma
Cyst with enhancing nodule (solid bit is T2 bright)
May calcify 35%
Temporal lobe epilepsy - most common tumour causing this
WHO 1
(DNETs don’t enhance and calcify a bit less and are T2 bubbly)
Pleomorphic xanthoastrocytoma
Low grade astrocytoma (2) Rare Cyst with enhancing nodule Temporal lobe epilepsy Calcification rare
Minor salivary glands
Small unnammed salivary glandular tissue in oral cavity, oropharynx, and mucosa of aerodisgestive tract
Adenoic cystic carcinoma
55% minor salivary gland
Idiopathic intracranial hypertension (pseudotumour cerebri)
Partially empty sella
Papilloedema, increased CSF along optic nerves
Enlarged meckels cave
Bilateral venous sinus stenosis (not thrombosis)
Headache, visual problems, tinnitis, photopsia (flashing lights)
Cranial nerve palsies may occur
Diagnose by CSF pressures, and imaging to exclude other causes
Spontaneous resolution may occur
CSF letting may treat, or acetazolamide
Slitlike ventricles (relatively uncommon)
(meningeal enhancement is in HYPOtension)
Moyamoya
Disease is idiopathic
Otherwise pattern or syndrome
Many causes:
Connective tissue: Marfans, Ehlers Danlos, SLE, antiphospholipid
Phakomas: NF1, TS
Infection: TB, bacterial meningitis
Blood dyscrasia: Sickle cell, PCV, aplastic and fanconi anaemia
Other: Graves, Downs, Aperts, UC, COC, radiation, atherosclerosis
Distal ICAs and COW, unilateral in 18%, vasculo-occlusive disease, with abnormal collaterals -
May haemorrhage from the collaterals - pial and basal ganglia collaterals
Susceptible to aneurysms, especially in posterior circulation
Orbital meningioma
Majority are extension from intracranial
20% are optic nerve sheath meningioma
Tram track sign on axial, non-enhancing dot on coronal, of enhancing mass surrounding non-enhancing nerve. Cf. glioma where nerve is enlarged
Temporal bone fracture
Currently otic sparing or otic involving
If otic capsule involved, Facial nerve paralysis, CSF leak, and sensorineural hearing loss all more likely (and epidural and subarachnoid haemorrhage)
Longitudinal (70%) and transverse (30%) old classification.
Longitudinal are associated with incudostapedial dislocation, conductive hearing loss, tympanic membrane rupture, facial paralysis in 25%. CSF ottorhea from tegmen tympnum involvement 15%
Transverse are associated with sensorineural hearing loss, >30% facial nerve palsy (50%), vertigo, otorhoea
Longitudinal - risk of developing cholesteatoma
Longitudinal more common - as above
Warthin tumour
Cystic 30% - more so than other parotid masses
Multicentric 20% - most common bilateral or multicentric tumour
Otherwise less common than pleomorphic adenoma
Old male predominant
Favour parotid tail (inferior superficial lobe)
Don’t calcify
Moderately enhance on CT
Often hypervascular on USS
Can be treated conservatively
AKA lymphomatous papillary cystadenoma aka adenolymphoma
Lymphoid stroma, double layer or epethilial cells (oncocytic appearance - abdundant mitochondria - granular appearance, polygonal)
Can arise in cervical lymph nodes.
T2 heterogeneous, T1 low/mixed (may haemorrhage), don’t enhance
Pleomorphic adenoma
Most common salivary gland tumour More common in superficial lobe of parotid Hypoechoic on ultrasound May have through transmission Calcification common Prominent enhancement on CT Small risk of malignant transformation Often recur after surgical excision Mixed histology
High T2, low T1, homogeneously enhance. May have high T1 centrally - mucoid.
Can appear entirely extraparotid if deep lobe, or parotid rest in parapharyngeal space
Frontotemporal dementia
Pick disease is an example. Outdated name, now called frontotemporal lobar degeneration. Pick disease reserved for if Pick bodies seen on path.
Caudate head volume may be reduced
Alzheimers v Lewy body
Alzheimers have memory distubrance first
Lewy have frontal disturbance first
Occipital hypoperfusion may aid in diffrentiation Lewy body from Alzheimers.
Occiptial lobes, basal ganglia and thalami, cerebellum, anterior cingulate are spared in Alzheimers.
Normal hippocampi size in Lewy body dementia, cf Alzheimers
Enlarged vestibular aqueduct
> 1.5mm
One of the most common causes of congenital sensorineural hearing loss
Often present as SNHL after minor trauma
Commonly associated with other abnormalities e.g. Mondini
Bilateral in 50-66%
Michel aplasia
AKA complete labyrinthine aplasia
Absent inner ear structures.
Cochlear implant contraindicated
Mondini malformation
AKA type 2 incomplete partition with large vestibular aqueduct
Incomplete apical 1.5 turns but preservation of basal turn
SNHL
Incomplete partition type 2
Part of spectrum of cochlear abnormalities, depending on timing of insult. Early results in Michel’s / complete labyrinthine aplasia.
Type 2 is 1.5 cochlear turns, with a cystic apex.
Sensorineural hearing loss.
Thyroid ultrasound
Calcification is the feature most closely associated with malignancy (but can be seen in benign processes)
Microcalc most specific, 95%, and associated with papillary thyroid ca
Intranodular flow usually malignant
Lymph nodes with increased flow suspicious
Coarse calcs may be seen in papillary or medullary, and in benign
Papillary and medullary hypoechoic
Follicular iso
Hyperechoic 5% chance of malignancy
Papillary may be cystic
Taller than wide, and irregular are supicious features
Lymph nodes enlarged suspicious, esp for papillary
Cancers tend to be hypo
A hypoechoic rim is a benign feature - follicular adenoma, but can also be seen in papillary cancer
Large cystic component, comet tail artifact, and hyperechoic are benign features.
Biopsy if <1cm and high suspicion
Or 1-1.5 and micro calc
Or >1.5 and solid or coarse calcs
Papillary thyroid
Microcalc on ultrasound
Nodal mets at presentation - may cavitate (cystic)
Associated with Cowdens (although Cowden is mosltly associated with follicular), Gardners
(cf follicular which favours haematogenous spread - follicular has Ras oncogene)
Orphan annie nuclear inclusions
Takes up iodine whereas medullary doesn’t.
Most common cancer. Also the most common in thyroglossal duct cysts.
Medullary thyroid cancer
MEN2 - so screen for phaes with MIBG or octreotide
VHL
NF1
Calcifies at primary and secondary sites
CEA and calcitonin (parafollicular C cells) (causes hypocalcaemia)
Will uptake MIBG if thyroid blocked by Lugols, 30% (potassium iodide)
Won’t concentrate radioactive iodine
PET 75% sensitive for mets
Anaplastic thyroid cancer
Typically in the elderly, with poor prognosis
Carotid and vertebral dissection
Extracranial more common
ICA more common than VA for both traumatic and spontaneous
Vertebral V2-3 (C6 transverse foramen to dura)
Carotid - 2cm above bulb to skull base. C1-2 level most common. Stroke usually occurs within a week, in at least 75%. Otherwise may have local signs e.g. Horners
Does not extend into petrous. May have seperate petrous.
5-20% of strokes 40-60
Subacute T1 crescent around flow void
Trauma (most common in vertebral, can’t find stats for carotid), connective tissue disease, FMD
DAI
80% non haemorrhagic
Dorsal brain stem, adjacent to superior cerebellar peduncle, associated with worse prognosis.
Lactate peak associated with worse prognosis.
Can have reversible diffusion restriction
Gray white interface mostly, then corpus callosum - mostly splenium
Vasospasm post SAH
40-80% imaging
20-30% clinically
4th to 10th day post bleed
Optic pathway glioma
33% occur in patients with NF1
Mesial temporal sclerosis
Most common cause of complex partial seizures
Cortical dysplasia is the most common dual pathology
Atrophic body>tail>head>amygdala
PET more sensitive than MRI
Germinoma
Most common germ cell tumour of pineal HCG normal Very responsive to radiotherapy Positive for placental alkaline phosphatase on immunochemistry More common in males
Pineal gland met
Rare
Lung, breast, GI, kidney
Pineocytoma
More common in females
WHO 1
May be cystic, appearing similar to pineal cyst
Slow growing and well circumscribed cf. pineoblastoma
Lhermette-Duclos
Rare tumour of cerebellum
AKA dysplastic cerebellar gangliocytoma
Probably a hamartoma, but considered WHO1
Cowden COLD (Cowden Lhermette Duclos) associations
Hypoattenuating, may calcify, doesn’t enhance
Striated
Herpes encephalitis
Spares basal ganglia
Often bilateral, assymetric
Involves insula, cingulate gyrus (but mostly temporal lobes and inferior frontal)
Mild mass effect
Bimodal, <20 (primary) >50 (reactivation)
95% HSV1
Haemorrhagic necrotising
HSV2 causes more herpetic meningitis, and more in neonates
Alterations in mood, memory, behaviour common
May present subacute with ataxia and seizures
Cowdry intranuclear inclusion bodies (also in CMV, varicella)
Gyriform enhancement
Brainstem more likely to be involved in immunocompromised
Cryptococcal infection
In AIDS
Followed dilated VR spaces
Atrophy, hydrocephalus, masses
Cryptococcomas, involve midbrain and basal ganglia
Granulomatous meningeal disease
Tends to affect basal pachymeninges - spares convexities
May produce masses with enhancement
Sarcoid, RA, TB, Wegeners, syphilis, fungal
Haemangiopericytoma
Rare
Solitary fibrous tumour of meninges
AVM
No mass effect
Contrast CT will detect 90%
Spetzle-Martin grading
Size <3cm 1, 3-6 2, >6 3
Eloquent cortex 1
Deep venous drainage 1
Overall is from 1-5
(Non eloquent is frontal, temporal, and cerebellar hemisphere)
Haemangioblastoma
20% produced EPO
Spine: Thoracic (50%), cervical (40%)
Prominent, dilated tortuous vessels on posterior cord surface
75% intramedullary
Almost never calcifies
Paravermian cerebellar - most common primary infratentorial neoplasm in adults
Choroid plexus hyperplasia
AKA villous hypertrophy of choroid plexus
Rare
Can result in communicating hydrocephalus
Ruptured aneurysm
Urgent treatment to prevent rebleeding permit aggressive vasospasm treatment
IV mannitol for herniation
Calcium antagonists
Clipping and coiling
Spinal ependymoma v astrocytoma
Astro in children, epend in adults
Astro expansile, poorly defined, several levels, heterogeneous enhancement
Epend NF2, moor well defined and homogeneous enhancement. Haemorrhage.
Ependymoma of spine don’t tend to calcify cf. brain do
Cellular ependymoma most common in thoracic cord
Ependymoma can cause communicating hydrocephalus through neoplastic arachnoiditis and adhesion formation
MS
Ovoid lesions, perpendicular to ventricular walls
Loss of hydrophobic myelin so increased T2
80% have spinal involvement. Cervical in 2/3.
12-33% have only spinal
Enhancement lasts 3 months. 90% disappear in 6 months
Parallel to long axis of cord
SEGA`
WHO 1
Almost exclusively TS
Marked contrast enhancement
Foramen of Monro typical
>1cm
Neurocytoma
Arise from septum pellucidum or ventricular wall
Intratumoral cyst like areas - T2 hetero
Well circumscribed, heavily lobulated
Bubbly
20-40 Commonly calcify Grade 2 Histo similar to oligodendoglioma Mild to moderate enhancement
Otitis media
Moraxella, haemophilus, stre pneumoniae
Moraxella is also 2nd most common COPD exac
Tolosa Hunt
Painful opthalmoplegia, cavenous sinus and orbital apex inflammation
Diagnosis of exclusion
Idiopathic
Pseudotumour can cause
Parathyroid adenoma
Abnormal parathyroid tissue is T2 very bright and avidly enhancing
Thyroid (33% (superior thyroid common), thyroid-thymus conduit (19%), thymus (15%)
Mot commonly anterosuperior mediastinum or low in neck
Cavenous haemangioma
Most common orbital lesion 80% intraconal (commonly lateral) Adult cavernous, paeds capillary (capillary more commonly extraconal) 2/3 in women for adults Painless proptosis, progressive
May have calcified phleboliths
Iso to muscle T1, hyper T2
Nasopharyngeal carcinoma
Considered separate to other head and neck SCC
Often centres fossa of Rosenmuller
Perineural spread, nodal involvement
Spread to parapharyngeal space most reliableimaging sign
T stage based on if involves parapharynx (2) bones (3), or intracranium (4)
EBV, diet, genes - increased risk in Chinese and Eskimos
And HPV
Keratinising type, same as other head and neck SCC, smoking and alcohol, ingested nitrosamines (Chinese diet)
Non-keratinising type, EBV, and particularly in asians
Retropharyngeal space
Anterior to prevertebral space, posterior to pharyngeal mucosal space
Contains nodes (of Rouviere) and fat
Goes from one carotid space to the other
Visible on CT
Spinal cord tracts anatomy
.
Capillary telangiectasia
Low flow vascular lesion Most common after DVA on imaging Asymptomatic Most in pons, cerebellum, spinal cord Associated with OWR Normal brain tissue insterspersed, in contrast to cavernoma Tend not to bleed Not seen on DSA, CT
Pulsatile tinnitus
Dehiscent jugular bulb Persitent stapedial artery - associated with small or absent foramen spinosum, or aberrant ICA Idiopathic intracranial hypertension Dural AVF Glomus tympanicum or jugulare AVM Vascular compression of cranial nerve 8
Tympanic membrane
Pars tensa is most of it, inferiorly
Top part if pars flaccida
Acquired cholesteatoma tends to perforate pars flaccida
Intraconal lesions
Glioma, meningioma, haemangioma, pseudotumour, lymphoma (more commonly extra), mets (both), varix
Conal lesions
Thyroid eye disease, pseudotumour, rhabdo
Extraconal lesions
Pseudotumour (commonly conal, can be anywhere - intraconal fat common, 90% unilateral), cellulitis / abscess, lymphoma (can be intra, or optic nerve sheath complex), mets (both), dermoid / epidermoid, lymphangioma, lacrimal gland tumour (superolateral - lymphoma and salivary gland tumour [adenoid cystic, BMT], also affected by sarcoid and pseudotumour)
Corpus callosum dysgenesis
Dilated occipital horns Widely placed ventricles Heterotopic gray matter association Associated with non-downs trisomy Colpocephaly (dilated trigones and occipital horns)
Spinal meningioma
Most commonly thoracic
Anterior cord surface cervical near foramen magnum next most common
Iso T1 and T2
Posterior vertebral body scalloping
Achondroplasia, acromegaly, ependymoma
Bone abnomalities - acromegaly, MPS, achondroplasia, ank spond
Dural ectasia -
Tumour / pressure - ependymoma, hydrocephalus
Scoliosis
Convex right in thoracic, left in lumbar, is typical for adult idiopathic
