Salivary Gland Imaging

Question 1

Why do we image salivary glands?

Answer 1

Obstruction
- salivary stone
- mucous plugs
- neoplastic obstruction

Dry mouth
- gland disease / systemic disease

Swelling of gland

Question 2

What is ultrasound?

Answer 2

High frequency sound waves that produce no ionising radiation

Question 3

Why is ultrasound good for imaging salivary glands?

Answer 3

Glands are superficially positioned

Can assess the parenchymal pattern, vascularity, dilation of ducts and assess for any neoplastic masses

Question 4

What symptoms may indicate obstructive salivary disease?

Answer 4

‘Meal time symptoms’

• prandial swelling and pain - swelling after / while eating
• sudden rush of saliva into mouth
• bad taste
• thick saliva
• dry mouth

Question 5

Aetiology of obstructive salivary gland disease?

Answer 5

Sialolith or mucous plug

80% salivary stones associated w/submandibular gland

80% of submandibular stones are radiopaque

Question 6

What is sialography?

Answer 6

Injected iodinated radiographic contrast liquid into salivary duct
- to identify obstruction
- 1 - 1.5ml

Question 7

Indications for sialography?

Answer 7

• investigating obstruction symptoms of salivary gland
• planning for access of gland for interventional procedures such as removal of stones or endoscopy

Question 8

Risks of sialogrpahy?

Answer 8

Discomfort

Swelling

Infection

Allergy to contrast liquid

Question 9

What are the normal sialogram findings of parotid and submandibular glands?

Answer 9

Parotid - tree in winter

Submandibular - bush in winter

Question 10

What is the selection criteria for basket salivary stone removal?

Answer 10

Stone must be mobile

Stone located within lumen or main duct distal to posterior border of mylohyoid (SMG)

Stone should be located distal to the hilum or at anterior border of gland (parotid)

Duct should be patent and wide enough to allow passage of stone

Question 11

What does a sjogrens salivary gland appear like?

Answer 11

Atrophied

Heterogeneous parenchymal pattern (leopard print)

Hypoechoic (darker)

Fatty infiltration

Question 12

What is a scintiscan?

Answer 12

Injection of radioactive technetium 99m

Assess how well the glands are functioning
- uptake to the glands if they are working well

Question 13

Why is ultrasound taken of a salivary gland swelling?

Answer 13

First line imaging technique to rule out obstruction or neoplasia

Question 14

Give an example of a benign salivary gland tumour and its typical ultrasound presentations

Answer 14

Pleomorphic adenoma

• Well defined margins
• encapsulated
• peripheral vascularity of tumour
• no lymphadenopathy

Question 15

Give an example of a malignant salivary gland tumour and its typical presentations on an ultrasound

Answer 15

Acinic cell carcinoma

• irregular and poorly defined margins
• increased internal vascularity
• lymphadenopathy

Question 16

When should imaging of minor salivary glands occur?

What imaging?

Answer 16

If enlarged or pathological

Ultrasound if superficial
MRI if deeper or bony involvement

Minor salivary glands, in general, have higher chance of malignancy if pathological