Other Imaging Modalities 1

Question 1

why do we image the salivary glands?

Answer 1

Obstruction:
- Mucous plugs
- Salivary stones (sialoliths)
- Neoplasia (uncontrolled/abnormal growth of cells)

Dry mouth

Swelling

Question 2

why is ultrasound good for salivary glands?

Answer 2

• Glands are superficially positioned
• can assess parenchymal pattern (function), vascularity ductal dilation or neoplastic masses

Question 3

what is an ultrasound?

Answer 3

• no ionising radiation
• high frequency sound waves (can’t be heard audibly)
• sound waves have short wavelength which are not transmissible through air (require coupling agent to help get sound waves into tissues)

Question 4

what is the imaging protocol for salivary gland obstruction?

Answer 4

1) Ultrasound

2) Plain Film (Mandibular true occlusal)

3) Sialography

Question 5

what is salivary gland obstructive disease & its symptoms?

Answer 5

obstruction of salivary gland(s)
- prandial swelling & pain (during food periods)
- bad taste
- thick saliva
- Dry mouth

Question 6

what is the aetiology of obstructive disease?

Answer 6

• Sialolith (salivary stone) or mucous plug

80% sialoliths associated with submandibular gland

80% of submandibular stones are radiopaque (white under xray)

Question 7

what is sialography?

Answer 7

• injection of iodinated radiographic contrast into salivary duct to look for obstruction
• Done with either panoramic, skull view or fluoroscopic approach
• very small volume contrast injected

Question 8

why do we do sialography?

Answer 8

• looking for obstruction or narrowing of duct causing symptoms
• planning for access for interventional procedures

Question 9

what are risks of sialography?

Answer 9

• discomfort
• swelling
• infection
• allergy to contrast (very rare)

Question 10

what does a NORMAL PAROTID GLAND look like in sialography?

Answer 10

a tree in winter, theres only branches and no leaves

Question 11

what does a NORMAL SUBMANDIBULAR GLAND look like in sialography?

Answer 11

a bush in winter, no leaves

Question 12

what does a sialogram look like if there’s CHANGES TO ACINAR TISSUE?

Answer 12

• snow storm appearance

Question 13

what are some technical considerations to be made during sialography?

Answer 13

• contrast medium going into oral cavity
• air bubbles in the tubing
• over-filling duct with contrast medium

Question 14

what is the selection criteria for stone removal in a salivary gland?

Answer 14

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

Question 15

A patient complains of dry mouth, and you suspect sjogren’s syndrome, what investigations can you carry out to confirm?

Answer 15

• blood test (autoantibodies)
• schirmer test (tears on paper)
• sialometry
• labial gland biopsy

Question 16

what are you looking for on ultrasound for suspected sjogren’s syndrome?

Answer 16

• atrophy
• heterogeneous parenchymal pattern (leopard print)
• hypoechoic (darker)
• fatty infiltration

Question 17

If a patient has a swelling, what is the first line imaging technique to rule out obstruction or neoplasia?

Answer 17

Ultrasound

Question 18

if patient has suspected neoplasia on ultrasound, what would you do next?

Answer 18

biopsy

Question 19

what are the ultrasound features of a BENIGN tumour?

Answer 19

• well defined
• encapsulated
• peripheral vascularity
• no lymphadenopathy (doesnt affect lymph nodes)

Question 20

what are the ultrasound features of a MALIGNANT tumour?

Answer 20

• irregular margins
• poorly defined
• increased internal vascularity
• lymphadenopathy (affecting lymph nodes)

Question 21

when would you image minor salivary glands?

Answer 21

only if enlarged or pathological suspected

Question 22

when would an mri be beneficial for minor salivary gland imaging?

Answer 22

If deeper or possible bony involvement

Question 23

in soft tissue imaging, when would MRI be considered?

Answer 23

for further investigation:
- vascular lesions
- too large to be seen on ultrasound in completeness