Other Imaging Modalities - Ultrasounds

Question 1

Why do we image salivary glands?

Answer 1

• Obstructions:
  -mucous plugs
  -salivary stones (sialoliths)
  -neoplasia
• Dry mouth (sjogrens has a characteristic presentation on an ultrasound)
• swellings

Question 2

Why is ultrasound good for salivary glands?

Answer 2

• glands are superficially positioned (apart from the deep lobe of the parotid)
• can assess parenchymal pattern, vascularity, ductal dilation or neoplastic masses
• Can give sialogogue (i.e. citric acid) to aid salivary flow and get better visualisation of dilated ducts on US

Question 3

If a salivary gland has increased vascularity, what is likely?

Answer 3

That it is inflamed

Question 4

Describe ultrasounds.

Answer 4

-no ionising radiation
-high frequency sound waves
-sound waves have a short wave length which are not transmittable through air and require coupling agent ot help sound waves get into tissues (the gel that is used)

Question 5

What is the imagine protocol for salivary gland obstruction?

Answer 5

Ultrasound then a plain film (mandibular true occlusal) then sialography (depends on what first 2 show)

Note: if you are a GDP and think there is a salivary stone can do a plain film then refer for ultrasound if negative

Question 6

Symptoms of obstructive salivary disease?

Answer 6

-‘meal time symptoms’ so prandial swelling and pain (eating/thinking about eating get presure and pain over salivary gland)
-‘rush of saliva into mouth’ which is salty/bad taste and thicker in consistency
-dry mouth

Question 7

What is the aetiology of salivary gland obstruction?

Answer 7

Either sialolith (salivary stone) or mucous plug

Question 8

Most sialoliths are associated with what gland?

Answer 8

80% associated with submandibular gland

Question 9

Are sialoliths normally radiopaque or radiolucent? What does this mean for imaging?

Answer 9

80% are radiopaque so should be picked up on plain film images

Question 10

What sialoliths are better seen with ultrasounds?

Answer 10

Mucous ones

Question 11

What is sialography?

Answer 11

-Injection of iodinated radiographic contrast into salivary duct (via duct oriface) to look for obstruction or stictures
-no LA required
-very small volume of contrast injected (1-1.5ml)

Question 12

Sialography can be done with what radiographic views?

Answer 12

Either panoramic (used at GDH), skull views or fluroscoptic approach

Question 13

What are the indications for sialography?

Answer 13

-looking for obstruction or stricture (narrowing) of salivary duct which could be leading meal time symtpoms
-planning for access for interventional procedures (basket retrieval of stones or baloon dilation of ductal strictures)

Question 14

What are the risk of sialography?

Answer 14

-discomfort
-swelling
-infection (if any infection present it will be pushed further into gland so if any signs of infections it should be postponed and AB’s prescribed)
-allergy to contrast (very rare but MRI is alternative as no contrast required)

Question 15

What are the normal findings of a sialography?

Answer 15

-parotid gland ‘tree in Winter’
-submandibular ‘bush in winter’

Question 16

If there are acinar changes, how will the sialography look? What changes might cause this?

Answer 16

‘snow-storm’ appearance

Advanced sjogrens or advanced chronic inflamamtion

Question 17

How many images need to be taken with sialography? When/what are the images that need to be taken?

Answer 17

2

1st = contrast phase with the cannula in place

2nd = during emptying phase with time delay

Question 18

What is the purpose of taking an image during the emptying phase?

Answer 18

Because allows the gland to work and produce saliva to excrete contrast

If there is still a lot of contrast after 5 mins etc then can indicate a problem

Question 19

Technical considerations for sialography?

Answer 19

-don’t overfill gland
-if use too small a cannula get contrast into mouth sitting on floor of mouth
-air in contrast syringe can lead to air locules that can be misdiagnosed as stones

Question 20

When are interventional procedures done for salivary glands?

Answer 20

-not done routinely in Scotland
-is an option in some cases rather than surgical removal of stone via incision (when not possible) or extra-oral removal of salivary gland (is too severe in the case)

Question 21

What interventional option is ther to try and remove stones? What is the problem with this?

Answer 21

Attempt to dilate strictures (narrowing) of the duct and break up the stones
Can required multiple attempts and stenting to keep the duct patent (prevent closure)
Sometimes not possible due to extent of scarring from chronic infection

Question 22

What is the selection criteria for stone removal?

Answer 22

1-stone must be mobile
2-stone must be located within lumen on main duct distal to posterior body of mylohyoid (SMG)
3-stone should be dital to hilum or at anterior border of the gland (parotid)
4-duct should be patent and wide enough to allow passage of the stone

Question 23

US for dry mouth typically done in pts with suspected Sjogren’s. The findings from the US used in correlation with what other investigations/clinical findings?

Answer 23

-blood tests (auto-antibodies)
-Schirmer test
-Sialometry
-Labial gland biopsy

Question 24

In US for Sjogrens you are looking for what?

Answer 24

-atrophy
-heterogeneous parenchymal pattern (leopard print)
-hypoeachoic (darker)
-fatty infiltration)

Note: chance for MALT lymphoma to develop so have frequent scans

Question 25

What is scintiscan?

Answer 25

-injection of radioactive technetium 99m to assess how well the glands are working
-uptake into glands if they are working well

Not really done as ultrasounds can show you this and scintiscan uses high radiation - difficult to justify

Question 25

What is scintiscan?

Answer 25

-injection of radioactive technetium 99m to assess how well the glands are working
-uptake into glands if they are working well

Not really done as ultrasounds can show you this and scintiscan uses high radiation - difficult to justify

Question 26

For swellings, ultrasound is the first line option to rule out what?

Answer 26

Obstruction or neoplasia

Question 27

If there is a neoplasia, what is required?

Answer 27

Biopsy

Question 28

Biopsy options for neoplasia?

Answer 28

-fine needle aspiration for cytopathological diagnosis
-core biopsy for tissue histopathological diagnosis (only done if considering lymphoma)

Question 29

How does a benign tumour look on US?

Answer 29

-well defined
-encapsulated
-peripheral vascularity
-no lymphadenopathy

Question 30

Example of benign salivary gland tumour?

Answer 30

pleomorphic adenoma Warthins tumour

Question 31

Examples of malignant salivary gland tumour?

Answer 31

-mucoepidermoid carcinoma
-acinic cell carcinoma
-adenoid cystic carcinoma

Question 32

How would a malignant tumour appear on an ultrasound?

Answer 32

-irregular margins
-poorly defined
-increased/tortuous internal vascularity
-lymphadenopathy

Question 33

What needs to be remembered when looking at tumours on ultrasounds?

Answer 33

LOW GRADE MALIGNANCIES MIMIC BENIGN LESIONS

(so still need biopsy)

Question 34

US is first line imaging for soft tissue lesions and possible biopsy if required. What should be considered for further investigation?

Answer 34

MRI

Question 35

When should MRI be considered for soft tissue lesions?

Answer 35

-vascular lesion
-lesion too large or too deep to be seen on ltrasound in completeness