other imaging modalities 1 Flashcards
what are the major salivary glands
3 pairs - parotid, sublingual, submandibular
parotid salivary gland
pair
largest,
Duct orifice in buccal mucosa adj to 1st and 6nd premolar
2 lobes - superficial close to skin, deep arund ramus - not on US but will to deep
submandibular salivary gland
location
inferior to manidbular and submandibular fossa
see in OPT
sublingual salivary gland
pair
smallest
under tongue, either side of intrinsic and extrinsic muslces of tongue
3 main reasons why image salivary glands
obstruction
dry mouth
swelling
obstruction of salivary gland can be due to
3
mucous plugs - parotid more likely to get mucous plugs (but serous secretions)
salivary stones (sialoiths)
neoplasia
why is ultrasound good for salivary glands
3
Glands are superficially positioned
* Just under subcutaneous tissue
* Apart from the deep lobe of the parotid (hidden deep to the ramus
Can assess parenchymal pattern, vascularity, ductal dilatation or neoplastic masses
* pattern of tissues in gland
* Inc vascularity - inflamed signed
* Widening of tube of saliva into mouth - indicates obstruction somewhere in duct
Can give a sialogogue (ie citric acid) to aid saliva flow
* Will allow better visualisation of dilated ducts
* Stimulates saliva, makes US images better – dilate tubes
imaging used for saliva gland assessment
ultrasound
ultrasound can look for what 4 characteristics of saliva gland tissue
parenchymal pattern
vascularity
ductal dilation
neoplastic massess
pattern of tissues in gland
* Inc vascularity - inflamed signed
* Widening of tube of saliva into mouth - indicates obstruction somewhere in duct
e.g. sialogogue
citric acid
role of silaogogue
aid saliva flow
will allow better visulisation of dilatred ducts
what is Ultrasound
No ionising radiation good
High frequency sound waves – Frequency that cannot be heard audibly
Sound waves have short wave length which are not transmittable through air
* Require coupling agent to help sound waves get into tissues
* Cannot transmit through air
describe anatomy seen in US of sublingual gland
Skin surface at top
Deeper in pt, work down screen
White horizontal lines - subcutaneous fat
Dark oval shaped on both side - ant bellies of digastric
Horseshow - mylohyoid
Ext tongue muscle in middle
Sublingual either side
US flips coronal view of pt
what is this ultrasound of?
Left submandibular glands
Subcutaneous fat above the light shade of grey glands
Dark area is facial artery - red
Mylohyoid then hyoglossus below
Duct leaves where blue line is and goes under mylo above hyo has a bend -where stones usually are
what is this?
ultrasound of right Superficial lobe of parotid - blue
Yellow - angle and ramus of mandible, sound waves stopped by them - hence cannot see deep lobe
Red lines - right masseter muscle
Accessory tissue pass over parotid to buccal fat pad - over masseter - need to cover all to ensure nothing missed
image protocol for salivary gland obstruction
3
ultrasound
plain film (e.g. mandibular true occlusal for submandibular stone)
sialography
Start with plain film and then move to US if plain film negative if on clinic and no access
US first as no ionsiation
salivary gland obstruction symptoms
6
“Meal time symptoms”
* Anytime thinking or eating – get pressure and pain over salivary gland
Prandial swelling and pain
“rush of saliva into the mouth”
Bad taste salty
Thick saliva
Dry mouth
aetiology of salivary gland obstruction
Sialolith or mucous plug
80% sialoliths (stone) associated with the submandibular gland
* Rest are typically mucous plugs in parotid
80% of submandibular stones are radiopaque
gland appearance on US
hypoecoic (darker)
stone appearance on US
hyperecoic
white/brighter
describe this ultrasound
Heterogenous appearance - mixed density parenchyma, looks chords compared to healthy gland
Dark area in gland - ductal dilation, likely due to stone
Follow into FOM to see if there is obstruction
* Check full ductal structure - likely more than one stone if have one
describe these US of right parotid
Stone iteself - Hyperechoic; Lobulated irregular surface
Calcified - sound waves cannot penetrate - get posterior shadowing
Position can make it not able to be removed, without removing gland
Far left - See calcified flecks with dark surrounding – can tell it is calcified and in gland itself despite being small
unhealthy gland characteristics on US
- Outline of gland not as clearly defined
- Merge into subcutaneous tissue
- Dark and homogenous - not healthy
descrive these US of left parotid with stone
Anterior - see small ductal dilation, edge of gland above masseter
Second area of dilation
Buccal fat region has massive area of ductal dilatation
Fits pattern of narrow of blockage anterior
Stone in buccal duct orifice by upper 6
* Dark posterior shadow = calcified
what is sialography
Injection of iodinated radiographic contrast into salivary duct to look for obstruction
* Looks for obstructions or strictures, Narrowing of duct
Done either with Panoramic (DPT), skull views (PA mandible and lateral oblique) or Fluoroscopic approach.
* Flu - direct visualization of contrast going in, but more radiation
* Static - just see before and after
No local anaesthetic (no needles or scalpels)
Very small volume of contrast injected (1.0-1.5ml)
* Isoosmolar and water based - no tissue reaction and safe to swallow (same contrast used for CT scans but much higher volume)
2 indications for sialography
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 balloon dilatation of ductal strictures)
adv of sialography
3
- Happening and causing symptoms
- Crude idea of how well gland is functioniong
- Where contrast there, wait 5mins so gland should be dye free but if not show suboptimal
parotid duct orifice
adj to upper 6 in buccal mucosa
submandibular duct orifice
lingual frenum on FOM
risks of sialography procedure
4
Discomfort
* Against flow of saliva - pressure
Swelling
Infection
* Cannot procede – push bacteria further in and create an acute infection of gland which is hard to tx
* Prescribe antibiotics and reappoint in 1 week
Allergy to contrast (very rare)
* MRI is alternative as no contrast used
procedure of sialograhy
Insert catheter
Inject contrast
Take radiograph
Cannula out
Rinse
Wait and take 2nd to see how emptied
normal findings for sialography
parotid gland - ‘tree in winter’
submandibular - ‘bush in winter’
if acinar changes - ‘snow storm appearance’
describe this image
normal sialography for parotid gland
Accessory lobe superior
Main duct goes to main lobe, breaks into 1st and 2nd branches as you go
describe this image
Normal submandibular sialograph
Slightly over filled - get blushing
* Easy to overfil
how many images to take for sialography
Contrast phase with cannula in place
* Emptying phase with time delay (approx. 5mins after)
* Allows gland to work and produce saliva to excrete contrast
describe these images
Acinar changes
* Adv sjorgrens
* See in lat oblique and PA
* Globular appearance of contrast
describe this image
Abnormal - submandibular duct
see dark defect, silaoth, into gland not much contrast - see genube (90 degree bend into gland from duct) defect there too - silaoth has created a ductal dilatation along it
describe these contrast and empty sialographies
dilated main duct
Narrow duct at posterior duct compared to mid-section
S shaped bend
* Abnormal ductal structure makes saliva flow even harder
Post contrast phase - not cleared
Chronic siladenitis, Secondary to obstruction
describe this case
Ductal dilation see on US
Then silaogram
* See large dilatation
* Narrowing - contrast cannot go through
* Gland itself has acinar changes
No difference in emptying phase
Likely gland removal as so severe structing
describe this contrast and empty sialographies
Stone over apex of lower left 6
* No contrast posterior into submandibular gland
* Complete stricture behind stone
Narrow to LL4 to 6 - stone is rocking backward and forward
* Can see in empty phase - moved forward
Good as amenable to intervention for removal
4 technical considerations for sialography
Careful not to overfill
Cannula to small - fall out - extravasated contrast
Pt complain of odd taste
Air locules in tube
* no air in syringe get air in contrast phase – mistake for a stone
interventional options for stones/strictures in saliva ducts/glands
Not routinely done in Scotland
* Balloon dilation, basket rotation, break up like kidney stones
Option in some cases rather than surgical removal of stone via incision or extra-oral removal of the salivary gland.
* Can attempt to dilate strictures (narrowing) of the duct
* Can need multiple attempts and stenting to keep the duct patent
* Sometimes not possible due to extent of scarring from chronic infection
* Cause relapse in strictures, may need stent
4 selection criteria for stone removal
strict
Stone must be mobile Not able to pass to remove if not mobile
Stone should be located within lumen on main duct distal to posterior border of mylohyoid (SMG)
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
dry mouth pts usually are
Typically patients with suspected Sjogren’s disease
Findings used in correlation with other investigations and clinical findings
* Blood tests (auto-antibodies)
* Schirmer test
* Sialometry
* Labial gland biopsy
appearance of salivary gland on US with sjogren’s disease
5
Atrophy
* Gland atrophy - look for other landmarks
Heterogeneous parenchymal pattern (leopard print)
* Outline of gland lost - merge into tissue
Hypoechoic (darker)
Fatty infiltration
Chance for MALT lymphoma to develop
* Need to routinely scan
Chronic hypersiladentitis - 1 gland
Sjogren’s -usually pairs or more
MALT lymphoma on US
hypoechoic
able tx compared to B cell lymphoma
can develop for sjogren’s - need to routinely scan
Scintisinscan
*Not really done now *
Injection of radioactive Technetium 99m
Assess how well the glands are working
* Light up - gland work, no light up - not work
* Uptake into the glands if they are working well.
US better at assessing function
Difficult to justify radiation
*Green circle - normal left submandibular
Right is not
Pink - subtle uptake left parotid
Right - not
Thyroid normal *
swellling investiagtion
Ultrasound is first line imaging technique to rule out obstruction or neoplasia
If neoplasia, biopsy is required
* Fine needle aspiration for cytopathological diagnosis
* Core biopsy for tissue histopathological diagnosis
benign swelling characteristics on US
4
- Well defined
- Encapsulated
- Peripheral vascularity
- No lymphadenopathy
e.g. Pleomorphic Adenoma, Warthins tumour
Bright behind – posterior enhancement indicator of cystic content
malignant swelling characteristics on US
4
- carcinoma
- Irregular margins
- Poorly defined
- Increased/tortuous internal vascularity
- Lymphadenopathy
e.g. mucoepidermoid carcinoma, acinic cell carcinoma, adenoid cystic
APART FROM LOW GRADE MALIGNANCY WHICH MIMICS BENIGN LESION – biopsy required
here
* Hypoechoic in parotid tail, Peripheral vascular, Slightly irregular
* 90% benign
Pt went to MRI - See mass in right parotid - larger than expected
any swelling that has malignant characteristics needs
biopsy
- Irregular margins
- Poorly defined
- Increased/tortuous internal vascularity
- Lymphadenopathy
soft tissue imaging protocol
Ultrasound is first line imaging
Possible biopsy if required
MRI should be considered for further investigation
* Vascular lesions
* Too large to be seen on ultrasound in completeness
MRI then CT
* MRI no radiation and better soft tissue contrast
what is this
ranula plunge into submandibular space
what is a lipoma
- Benign fatty lump
- Sit in buccal mucosa space
- Ovoid shape
- Dark and fat striation through mass parallel to skin surface
No blood supply (change to liposarcoma
what is a sebeous cyst
- Within skin itself
- Not clear if in subcutaneous or in submandibular salivary gland
- Defined appearance, hypoecho, see particles floating
