Other Imaging Types Flashcards
why do you image the salivary glands
obstructions
dry mouth
swellings
why is ultrasound a good option for salivary imaging
glands are superficially positioned
can assess parenchymal pattern, vascularity, ductal dilatation or neoplastic masses
can give a sialagogue
what are the features of an ultrasound
no ionising radiation
high frequency sound waves
need coupling agent due to short wave length
what is the imaging protocol for obstructive disease
ultrasound
plain film
sialography
what are the features of obstructive disease
meal time symptoms
prandial swelling and pain
rush of saliva into mouth
bad taste
thick saliva
dry mouth
what is the aetiology of obstructive disease
sialolith or mucous plug
what gland are most sialoliths associated with
submandibular gland
what is the process of sialography
find duct orifice
widen duct to place cannula
inject contrast and take radiographs
what are the indications for sialography
looking for obstruction or stricture of salivary duct which could be leading meal time symptoms
planning for access for interventional procedures
what are the risks of sialography
discomfort
swelling
infection
allergy to contrast
what would a normal parotid gland look like on sialography
tree in winter
what would a normal submandibular gland look like on sialography
bush in winter
what would sialography look like if there were acinar changes
snow storm
when do you take images for sialography
with cannula in place for contrast phase
emptying phase with time delay
what technical considerations are there for sialography
contrast into oral cavity
air bubbles in tubing
over-filling
what is the selection criteria for stone removal
stone must be mobile
stone should be located within lumen on main duct distal to posterior border or mylohyoid
stone should be distal to hilum or at anterior border of parotid gland
duct should be patent and wide to allow passage of stone
what do you look for on a radiograph with dry mouth
atrophy
heterogenous parenchymal pattern
hypoechoic
fatty infiltration
if the gland is neoplastic what tests are needed
fine needle aspiration for cytopathological diagnosis
core biopsy for tissue histopathological diagnosis
what would a benign lesion look like
well defined
encapsulated
peripheral vascularity
no lymphadenopathy
what would a malignant lesion look like
irregular margins
poorly defined
increased/tortuous internal vascularity
lymphadenopathy
what is an MRI useful for
pre-surgical assessment and deep margins on lesions that may not be seen on ultrasound
do before biopsy
when would an MRI be considered
further investigations like vascular lesions or lesions too large to see on ultrasound
what is used for bony imaging
CBCT or CT
MRI for marrow changes
what are the features of CBCT
low dose multi-planar imaging
images made from isotropic voxels
cone shaped beam
low dose
poor soft tissue contrast
radiographic contrast no required
patient sitting up/standing
