4 - Other imaging modalities 1 Flashcards
What are indications for imaging the salivary glands?
- obstruction
- dry mouth
- swellings
What can cause obstruction in the salivary glands?
- mucous plugs
- salivary stones (sialoliths)
- neoplasia
In which gland are mucous plugs most common?
Parotid
In which gland are sialoliths most common?
Submandibular
What is used for imaging of salivary glands?
Ultrasound
Why is ultrasound good for imaging salivary glands?
- glands are superficial
- parenchymal pattern, vascularity, ductal dilation and neoplastic masses can be viewed on US
What can be given to improve an US of the salivary glands?
- sialogogue
- citric acid
- allows better visualisation of dilated ducts
What is ultrasound?
- no ionising radiation
- high frequency sound waves that bounce back off structures to create an image
- requires coupling agent as the short wave length is not transmissible through air
What is the imaging protocol for salivary gland obstruction?
- US
- plain film (mandibular true occlusal)
- sialography
What is the presentation of obstructive gland disease?
- meal time symptoms, swelling and pain
- rush of saliva into mouth
- bad taste (salty)
- thick saliva
- xerostomia
Define prandial.
Related to meal times and eating
What is sialography?
- injection of iodinated radiographic contrast into duct
- combined with OPT, skull views or fluoroscopic approach
What are the indications for sialography?
- looking for stricture or obstruction of duct
- planning for access for interventions
What are the risks of sialography?
- discomfort
- swelling
- infection
- allergy to contrast (rare)
How are normal findings described in sialography?
- parotid gland “tree in winter”
- submandibular gland “bush in winter”
How are acinar changes described in sialography?
“Snow storm appearance”
What cause acinar changes in the salivary glands?
Sjogrens
What two images are taken in sialography?
- contrast phase with cannula in place
- emptying phase with time delay
What technical considerations are there with sialography?
- contrast in oral cavity
- air bubbles in tubing
- overfilling can cause blushing and discomfort
What is the selection criteria for stone removal?
- mobile
- duct is patent and wide
- located within lumen on main duct distal to mylohyoid (SMG)
- located distal to hilum or anterior border of gland (parotid)
What changes are you looking for on ultrasound for sjogrens syndrome?
- atrophy
- leopard print pattern
- darker areas
- fatty infiltration
What is scintiscan?
- injection of radioactive Technetium 99m
- assesses gland function
- uptake means glands are working
What is the first line imaging technique for swelling?
Ultrasound
Describe the features of a benign lesion on ultrasound.
- well defined
- encapsulated
- peripheral vascularity
- no lymphadenopathy
Describe the features of a malignant lesion on ultrasound.
- poorly defined
- irregular margins
- increased/tortuous internal vascularity
- lymphadenopathy
What is a SUMP?
Salivary gland neoplasm of unknown malignant potential
When should MRI be considered for further investigation?
- vascular lesions
- too large to be seen on US
- possible bony involvement
