Module 6: H + N (not spine) Flashcards
petrous apex
can get asymmetric marrow
what MRI sequence is useful and why
STIR fat satruation.
remove fat, can show a cholestrol grnauloma which might otherwise be hidden
Cephaloceles
what is it
herniation of CNS content through a cranium defect
two important carotid artery variant anatomy to be aware of
stapedial artery
aberrant internal carotid
what is the most common petrous primary lesion
cholestrol granuloma
cholestrol granuloma on MRI
T1 and T2 bright
T2 dark haemosiderin ring
what is a cholestrol grnauloma made from
blocked air cells with haemorrhage and inflammation continuining
What is a cholesteatoma
epidermoid (ectopic epithelial tissue)
congenital
How to define a choleastoma from a cholestrol granuloma
T1 dark for choleastoma and restrict diffusion
granuloma T1 and 2 are bright
otomastoiditis
trigeminal neuropathy
lateral rectus palsy
grandenigo syndrome
Endolymphatic sac tumour
ax to what condition
grow into where
how will they appear on CT
MRI?
vHL
CPA
calcifcaiton on CT
MRI - T2 bright
Paraganglioma in jugular region present with q
hoarse voice from vagus nerve
Large vestibular aqueduct syndrome is what
bony canal between vestibulae(inner ear) and endolymphatic sac.
enlarged causes progressive sensorineural hearing loss
VA vs PSCC size
in vestibular aqueduct syndrome
normall VA is not larger than the PSCC.
MRI appearance of labyrinthitis
inflammation of the membranous labyrinth.
cochlea and semicircular cancals enhance on T1 post contrast
what happens in layrinthitis ossificans
ossification of the membranous labyrinth
causes sensori neural hearing loss
two types of otosclerosis
fenestral
retrofenestral
Fenestral otosclerosis
bony resorption anterior to the oval window,
Footplate will fuse to the oval window
Retrofenstal otosclerosis
more severe form.
demineralization around the cochlea.
sensori neurla component. Bilateral and symeetric nearly 100% of the time
otitis media is infection where
middle ear
effusion
why do downs more commonly get otitis media
horizontal eustachian tube
definition of chronic for otitis media
6 weeks of fluid
complications of otitis media
coalescent mastoiditis
facial nerve pasly
dural sinus thrombosis
meningitis and labyrinthitis
Labyrinthine fistula can result from
a cholesteatoma
lateral semicircular canal most often involved in a fistula
superior semicircular canal dehiscene can cause
noice induced vertigo