Other Imaging Modalities

Question 1

Why do we need to image salivary glands?

Answer 1

Obstruction
- Via mucous plugs
- Via salivary stones (sialoliths)
- Via neoplasia

Dry Mouth to exclude sjogrens syndrome

Swelling

Question 2

Why is ultrasound good for salivary sound imaging?

Answer 2

• Glands are superficially positioned (apart from deep lobe of parotid which is hidden deep in ramus)
• Can assess parenchymal pattern, vascularity, ductal dilation or neoplastic masses
• Can give a sialagogue to aid salivary flow to allow better visualisation of structures

Question 3

What is Ultrasound?

Answer 3

• No ionising radiation to create images
• High frequency sound waves (not heard audibly)
• Sound waves have short wave length which not transmittable through air (require coupling agent to create imaging)

Question 4

What is the imaging protocol for salivary gland obsruction?

Answer 4

• Ultrasound
• Plain film (true mandibular occlusal)
• Sialography

Question 5

What symptoms will pts complain of if there is obstructive disease present?

Answer 5

• Meal time symptoms
• Prandial swelling and pain
• Rush of saliva into mouth
• Bad taste
• Thick saliva
• Dry mouth

Question 6

What is the aetiology of obstructive disease?

Answer 6

• Unusually a sialolith or mucous plug
• 80% sialoliths ass with submandibular gland
• 80% submandibular stones radiopaque

Question 7

Describe what you see in this radiograph

Answer 7

• Presence of two large submandibular sialolith extending from duct orifice to mandibular molars

Question 8

What is Sialography?

Answer 8

• Very small vol of Injection of iodinated radiographic contrast into salivary duct to look for obstruction
• Done with either Panoramic, skull views of fluroscopic approach

Question 9

What are the indications of sialography?

Answer 9

• Looking for obstruction or stricture(narrowing) of salivary duct which could be leading meal time symptoms
• Planning for access for interventional procedures (basket retrieval of stones or endoscopy)

Question 10

What are some risks of Sialography>

Answer 10

• Discomfort
• Swelling
• Infection
• Allergy to contract (very rare) can use MRI as alternative

Question 11

What is the procedure of Sialography?

Answer 11

• Locate duct orifice
• Dilate duct
• Cannula placed into duct
• Inject contrast and take radiographs
• Remove canula and allow for excretion of injection
• Take 2 images - contact phase and emptying phase

Question 12

What are normal findings of sialograph?

Answer 12

• Parotid gland ‘tree in winter’
• Submandibular ‘bush in winter’ (more rounded)
• If acinar changes ‘snow storm appearance’

Question 13

Describe this contrast image finding

Answer 13

• Sialography procedure or right submandibular gland
• See the contrast thoughout the duct and see a blockage about 80% of way through
• The salivary stone is being passed through the duct causing temp obstruction

Question 14

Describe what this sialography procedure contrast radiograph is showing

Answer 14

• Right submandibular gland
• Slight subtle obstructions where red pointer is likely to be mucous plugs
• Stricture of duct towards end
• Duct dilatation towards genome
• Filling defect shows in duct

Question 15

Describe what is happening in this sialography radiograph

Answer 15

• Narrowing of duct in left submandibular gland
• Showing complete stricture and closure of duct due to salivary stone
• No gland being contrasted due to stricture closure

Question 16

What are some technical considerations for sialography?

Answer 16

• Contrast into oral cavity
• Air bubbles in the tubing
• Over filling ‘blushing’

Question 17

What are the treatment options of salivary stones? - Not routinely done in Scotland

Answer 17

• Surgical removal of stone via incision of EO removal salivary gland
• Dilate strictures via stent

Question 18

What selection criteria for stone removal?

Answer 18

• Stone must be mobile
• Stone should be located within lumen on main duct duct distal to posterior border of mylohyoid
• Stone should be distal to hilum or at anterior border of gland (parotid)
• Duct should be patent and wide to allow passage of stone

Question 19

Pt has dry mouth and you suspect sjogrens disease what other investigations can be used to diagnose?

Answer 19

• Blood tests (autoantibodies)
• Schirmer test
• Sialometry
• Labial gland biopsy

Question 20

When suspected sjogrens what ultrasound findings are we looking for?

Answer 20

• Atrophy
• Heterogenous parenchymal pattern (leopard print)
• Hypoechoic (darker)
• Fatty inflitration

Question 21

What is a Scintiscan?

Answer 21

• Injection of radioactive Technetium 99m
• Assesses how well the glands are working via uptake

Question 22

What are the ultrasound findings of benign tumour?

Answer 22

• Well defined
• Encapsulated
• Peripheral vascularity
• No lymphadenopathy

Question 23

What are the ultrasound findings of malignant tumours?

Answer 23

• Irregular margins
• Poorly defined
• Increased / tortuous internal vascularity
• Lymphadenopathy

Question 24

When is MRI useful in obstructive disease?

Answer 24

• Pre surgical assessment and deep margiins of lesions that can’t be seen on ultrasound
• Do before a biopsy

Question 25

When would you do extra tests for minor salivary glands?

Answer 25

• Image if enlarged or pathological
• Ultrasound if superficial
• MRI if deeper or poss bony inolvement

Question 26

Do minor or major salivary glands have higher chance of malignancy?

Answer 26

• Minor salivary glands have higher chance if pathological

Question 27

Why is MRI used for TMJ imaging?

Answer 27

• Can see the disc using MRI
• Determine if with or without reduction and which direction the disc moves in relation to the condyle

Question 28

Compare the use of CT vs MRI

Answer 28

• MRI no radiation dose to pt
• MRI scan takes longer
• More contraindications for MRI including pacemakers, cochlear implants and claustrophobic
• MRI better for assessing perineural spread, bone invasion via bone marrow change, soft tissue characterists of lesion