radiology Flashcards
what do the majority of cysts appear like on the radiology
radiolucent
how do all the common pathologies appear on a radiograph
radiolucent
what is radiolucency in bone caused by
- resorption of bone
- decreased mineralisation of bone
- decreased thickness of bone
what can differential diagnosis’ gained by radiographic features provide us with
- to indicate the need/ type of further investigation
- to avoid unnecessary surgery
- to prompt urgent management
what is a cyst
pathological cavity having fluid, semi-fluid or gaseous contents which is not created by the accumulation of pus
what is the most prevalent type of pathological radiolucency in the jaws (excluding periapical peridontitis)
cyst
what % of jaw cysts are made up from odotongenic cysts?
90
what two categories are within odontogenic cysts
- developmental
- inflammatory
what two categories are within non-odotogenic cysts
- developmental
- other
what is the first step if differential diagnosis of any lesion
slip into one of three categories:
- anatomical
- artefactual
- pathologcial
what would you do for an radiolucent anatomical lesion
nothing
what would you do for an radiolucent artefactural lesion
nothing
what would you do for a radiolucent pathological lesion
step in with treatment
name the 7 descriptions of radiolucencies
- site
- size
- shape
- margins
- internal structure
- effect on adjacent anatomy
- number
how should “site” be described when describing a radiograph
- where is it
- is it close to a notable structure
- what is its position relative to particular structures
how should “size” be described when describing a radiograph
- measure dimensions
- describe the boundaries
what can we do to accurately assess the size of a radiolucent lesion
take a CBCT
how can locularity be described
- unilocular
- pseudolocular
- multilocular
how can the general shape of a radiolucent lesion be described
- rounded
- scalloped
- irregular
what shape are most radiolucent lesions
rounded
how can the margins of a radiolucent lesion be described
- well defined
- poorly defined
if the margins of a radiolucency are well defined, what other description goes along with this
- corticated
- non-corticated
what does corticated mean
thin area of dense bone surrounding the lesion
what description can go along with poorly defined margins that would cause concern of malignancy
- ragged
- moth eaten
what cant the margins of lesions indicate about them
nature of them - benign or malignant
what type of margins suggest a benign lesion
corticated margins
if the margins of a radiolucency are moth eaten then what might this indicate
malignancy
what type of margins do cysts generally have
well defined and corticated
when might the margins of a cyst become poorly defined
if they are infected
what will happen to the margins of a cyst if its infected
will become poorly defined
if a cyst is infected, what might it be mistaken for on the radiograph
malignancy
how can the general internal structure of a radiolucency be described
- entirely radiolucent
- radiolucent with some internal radiopacity
- radiopaque
what is the most common type of general internal structure seen on a radiolucency
entirely radiolucent
what other details might the internal structure of a radiolucency be described with
- amount
- bony septae
- particular structure
how might bony septae appearing in a radiolucency be described
- thin/ coarse
- prominent/ faint
- straight/ curved
what particular structures may be seen radiographically inside a lesion
enamel or dentine radiodensity
why should the involvement of a tooth be described for a radiolucency
position may aid in diagnosis
where can a radiolucency be if involved with a tooth
- around apex
- at side of root
- around crown
- around entire tooth
what could a radiolucency around the apex of a tooth be
radicular cyst
what could a radiolucency at the side of a tooth be
periodontal/lateral cyst
what could a radiolucency around the crown of a tooth be
dentigerous cyst
what could a radiolucency around the entire tooth be
calicifying odontogenic epithelial tumours
what does the involvement of tooth on the radiograph often indicate about the nature of the lesion
related to the tooth
why must you not a assume a lesion is related to a tooth
proximity may be incidental - alot of bone space made up by teeth so could be a coincidence
what can the affect on adjacent anatomy tell us about a lesion
indicate the nature of a lesion and aid in its diagnosis
what can cysts expand easily through
trabecular bone
what do cysts struggle to expand through
cortical bone
how might aggressive pathologies be recognised on a radiograph
can grow quickly and be more destructive in its expansion
how might cyst like pathologies affect bone
- displacement of cortices
- perforation of cortices
- sclerosis of trabecular bone
what are tumours able to expand through that cysts are not
all types of bone
what can cyst like pathologies do to IANcanal/sinus/nasal cavity
- displacement
- erosion
- compression
name 5 things that cyst like pathologies can do to teeth
- diaplacement/impaction
- resorption
- loss of lamina dura
- widening of PDL space
- hypercementosis
how many lesions do most pathologies occur as
1
what cyst is known to occur bilaterally
paradental cyst
what should you suspect if there are more than 2 pathologies present
a syndrome
what shape will a residual cyst be
unilocular and rounded
what margins will a residual cyst have
well defined and corticated
what will the internal structure of a residual cyst show
entirely radiolucent
will a residual cyst have tooth involvement
no
many different periapical radiolucencies can present with similar radiographic features, what info should you consider to help decipher what it is
- clinical signs and symptoms
- condition of tooth
- pt demographic
what is the most common pathological radiolucency in the jaws
radicular cyst
what % of cysts does a radicular cyst make up
70
what type of cyst is a radicular cyst
odontogenic inflammatory
what is a radicular cyst initiated by
chronic inflammation at the apex of a tooth due to pulp necrosis
what is a radicular cyst ALWAYS associated with
non-vital tooth
describe the pathway to radicular cyst formation
- pulp necrosis
- periapical periodontitis
- periapical granuloma
- radicular cyst
what age are radicular cyst most common in
60-70
what % of radicular cysts occur in age group 60-70
70%
what gender is more prone to radicular cysts
=
where are the majority of radicular cysts found
maxilla
what % of radicular cysts are found in the maxilla
60%
what % of radicular cysts are found in the mandible
40%
how do radicular cysts often present clinically
asymptomatic
when will a radicular cyst become symptomatic
once infected
how fast do radicular cysts grow
slow growing - limited expansion
can radicular cysts be differentiated from periapial granulomas from the radiograph
not really
how would you tell the difference between a radicular cyst and periapical granuloma from the radiograph
radicular cyst is larger
above what diameter would you expect a lesion to be a radicular cyst rather than a periapical granuloma
15mm
what shape will a radicular cyst have on the radiograph
rounded and unilocular
what margins will a radicular cyst have
well-defined and corticated
what will the internal structure of a radicular cyst show
entirely radiolucent
does a radicular cyst have tooth involvement? if so how?
yes
associated with root margins and continuous with lamina dura
what effects can a radicular cyst have
displace teeth
what can a long standing radicular cyst cause
resorption
when might you see several radicular cysts
grossly carious dentition
where is the site of a radicular cyst
apex of non-vital tooth
name two variants of a radicular cyst
- residual cyst
- lateral radicular cyst
what is a residual cyst
when the pathology persists after XLA or successful RCT
what is a lateral radicular cyst associated with
lateral canal of a non-vital tooth
where is a lateral radicular cyst located
side of a tooth
what type of cyst is a dentigerous cyst
odontogenic developmental
what is a dentigerous cyst caused by
cystic change of the the dental follicle
what is a dentigerous cyst associated with
crown of an unerupted/impacted tooth
what is the most common tooth to have a dentigerous cyst on
mandibular 3rd molar
what is the incidence of a dentigerous cyst
20%
what is the second most common type of cyst
dentigerous cyst
when is a dentigerous cyst most common (age)
2nd -4th decades
what gender is more likely to have a dentigerous cyst
male
where is a dentigerous more likely to be found
mandible
what is the dental follicle
normal anatomical structure that surrounds the crown of an unerupted tooth
what are the margins of a dentigerous cyst like
well defined and corticated
what kind of shape will a dentigerous cyst have when large enough
scalloped
what internal structure will a dentigerous cyst have
entirely radiolucent
will a dentigerous cyst have tooth involvement? if so then how?
yes
continuous with CEJ
what effects can a dentigerous cyst have
- displacement of tooth
- external root resorption
- displacement of adjacent structures
when would you consider there to be a dentigerous cyst instead of just an enlarged follicle
when the follicular space is >5mm
what size is a normal follicular space
2-3mm
when should you assume there is a dentigerous cyst present
when follicular space is >10mm and asymmetrical
what should you do if youre unsure if there is a dentigerous cyst or just an enlarged follicle
monitor or send for surgical management
what type of cysts are inflammatory collateral cysts
inflammatory odontogenic
what are the two types of inflammatory collateral cysts
- paradental cyst
- buccal bifurcation cyst
what are inflammatory collateral cyst associated with
vital tooth
what % of odontogenic cysts do inflammatory collaterals make up
2-7
what age group are inflammatory collateral cysts most common in
1st - 2nd decade
what might be the only symptom of a inflammatory collateral cyst
swelling around the molar teeth
which tooth is a mandibular buccal bifurcation cyst most often associated with
mandibular 1st molar
where does a paradental cyst most commonly occur
distal aspect of partially erupted mandibular 3rd molar
what size are inflammatory collateral cysts
<25mm
what shape are inflammatory collateral cysts
unilocular and rounded
what margins do inflammatory collateral cysts have
well defined and corticated
what internal structure will inflammatory collateral cysts have
entirely radiolucent
do inflammatory collateral cysts have tooth involvement
yes –> furcation
what effects do inflammatory collateral cysts have
tilting of tooth
cortical displacement
how many inflammatory collateral cysts often occur at the same time
just one or bilateral
what type of cyst is a keratocyst
developmental odontogenic
do keratocysts have any relationship to teeth
no
what is the recurrence rate of keratocysts
high
when might a keratocyst become clincially relevant
when becomes large enough
are keratocysts common
no - rare
when are keratocysts most common
2nd to 3rd decades
what gender more commonly get keratocysts
male
where are keratocysts most often found
mandible
where in the mandible are keratocysts often found
posterior
what were keratocysts classed as until 2017
tumours
what shape do keratocysts present as
psuedolocular, multilocular and scalloped
what margins do keratocysts have
well defined and corticated
what internal structure do keratocysts have
entirely radiolucent
what effects do keratocysts have
- marked expansion of trabecular bone
- limited displacement of cortices
- minimal displacement of teeth
- rarely root resorption
when might there be multiple keratocysts
if syndromic
what syndrome presents commonly as multiple keratocysts
basal cell naevus/ gorlin glotz syndrome
in addition to multiple keratocysts what other presentations will basal cell naevus have
- multiple basal cell carcinomas
- palmer and plantar pitting
- calcification of intracranial dura matter
are the keratocysts in basal cell naevus any different to normal keratocysts
no identical
what is the only difference between keratocysts in basal cell naevus and normal keratocysts
they occur at a younger age eg 15-19
what type of tumour is ameloblastoma
benign epithelial odontogenic tumour
how fast do ameloblastomas grow
slowly
what are the recurrence rates of ameloblastoma
high
is ameloblastoma painful?
not typically
what is the most common odontogenic tumour
ameloblastoma
when is ameloblastoma most common
4th to 6th decades
where do most ameloblastomas occur
posterior mandible
what % of ameloblastomas occur in the posterior mandible
80%
what gender are more prone to ameloblastoma
male
what are the two radiological types of ameloblastoma
- multicystic (multilocular)
- unicystic (unilocular)
what % of ameloblastomas are multicystic
85-90%
who is more likely to have a unicystic ameloblastoma
younger pts
what notable quality is there is unicystic ameloblastoma
lower recurrence rate
what are the 3 histological types of ameloblastoma
- follicular
- plexiform
- desmoplastic
what quality do some rarer types of ameloblastoma have
radiopaque
what appearance will some multilocular/cystic ameloblastomas have radiologically
coarse septae causing “soap bubble” appearance
what will the margins of ameloblastoma appear like
well defined and corticated
what is the internal structure of ameloblastoma
radiolucent
does ameloblastoma have tooth involvement
no
what effects does ameloblastoma have
thinning of cortices and external root resorption
is the growth of ameloblastoma constrained by the cortical bone
no
how many ameloblastomas will appear at one time
1
what type of tumour is an odontogenic myxoma
benign mesenchymal odontogenic tumour
what is the recurrence rate of odontogenic myxoma
high
what % of odontogenic tumours do odontogenic myxoma make up
3-6%
when are odontogenic myxomas most common
3rd decade
what gender is more prone to odontogenic myxoma
=
where are odontogenic myxomas more likely to occur
mandible
where in the mandible are odontogenic myxomas most often seen
premolar/molar
what shape will odontogenic myxoma have radiographically
multilocular and scalloped
may have coarse septae causing soap bubble appearance
what shape might small odontogenic myxoma have
unilocular
what margins will a odontogenic myxoma have
well defined thin corticated margin
what internal structure will odontogenic myxoma show
radiolucent
do odontogenic myxoma have tooth involvement
no
what effects do odontogenic myxoma have
- larger lesions displace teeth and cortices
how many odontogenic myxomas will appear at one time
1
what type of cyst is a nasopalatine duct cyst
developmental non-odontogenic cyst
what do nasopalatine duct cysts arise from
nasopalatine duct epithelial remnants
where do nasopalatine duct cysts occur
anterior maxilla
what characteristic symptom will a pt with nasopalatine duct cyst have
salty taste
what is the most common non-odotogenic cyst
nasopalatine duct cyst
what is the incidence of nasopalatine duct cyst
1%
when is nasopalatine duct cyst most common
4th to 6th decades
what gender is more prone to nasopalatine duct cyst
male
what is nasopalatine duct cyst also known as
incisive canal cyst
where do nasopalatine duct cysts always occur
anterior maxilla in the midline
how big are nasopalatine duct cysts
6-30mm
what shape are nasopalatine duct cyst
- heart shaped
- unilocular, rounded and symmetrical
- can be psuedolocular and lop-sided
why do nasopalatine duct cysts have a heart shaped appearance
because of the superimposed anterior nasal spine
what margins do nasopalatine duct cysts have
well defined and corticated
what internal structure do nasopalatine duct cysts have
entirely radiolucent
do nasopalatine duct cysts have tooth involvement
no - but next to incisor roots
what effects do nasopalatine duct cyst have
displacement of incisors, palatal expansion
how many nasopalatine duct cysts will appear at once
1
what shape is the incisive fossa on a radiograph
oval
is the incisive fossa corticated on radiographs
no
what diameter should make you assume the radiolucency is just the incisive fossa
<6mm
what diameter of radiolucency would you consider monitoring to decipher whether it is nasopalatine duct cyst or just the incisive fossa
6-10mm
what diameter of radiolucency would you suspect is a nasopalatine duct cyst
> 10mm
what type of cyst is a solitary bone cyst
non-odontogenic lesion
what are the other names for solitary bone cysts
simple/traumatic/haemorrhagic bone cyst
is a solitary bone cyst technically a cyst
no
do solitary bone cysts commonly have symptoms
no
when are solitary bone cysts most common
2nd decade
what gender is more likely to have solitary bone cysts
male
where are solitary bone cysts most common
mandible
what might solitary bone cysts occur in conjunction with
other pathology eg fibro-osseous lesion
what is the most common site for solitary bone cysts
posterior mandible
how big are solitary bone cysts
<30mm
what shape are solitary bone cysts
unilocular or psuedolocular or scalloped
what are the margins of solitary bone cysts like
variable
what is the internal structure of solitary bone cysts
entirely radiolucent
is there any tooth involvement with solitary bone cysts
no
what effects do solitary bone cysts have
typically none - rarely displacement of teeth
how many solitary bone cysts occur at one time
1
is stafnes cavity a cyts?
no
what is stafnes cavity
depression on the cortical bone
what does stafnes cavity contain
salivary or fatty tissue
does stafnes cavity have any symptoms
no
when is stafnes cavity most common
5th - 6th decade
what is stafnes cavity thougth to be linked to
salivary glands
where does stafnes cavity occur
lingual aspect on the mandible
what is another name for stafnes cavity
stafnes idiopathic bone cavity
what site does stafnes cavity often occur
body of mandible - sometimes the ramus
what size is stafnes cavity
<20mm
what shape is stafnes cavity
unilocular and rounded
what margins does stafnes cavity have
well defined and corticated
does stafnes cavity have any tooth involvement
no
what effects does stafnes cavity have
typically none - rare displacement of adjacent structures
how many stafnes cavitys occur at one time
1
what can happen in infected cysts that might make you think they are malignant
lose their well defined corticated margins
what should you always check for clinically if a pt has a cyst
clinical signs of secondary infection
what would be 3 signs of secondary infection of a cyst
- pian
- soft tissue swelling/ redness/ hotness
- purulent exudate
why should you not assume that a cyst is connected to a tooth
there are only so many places the cyst can be in the jaws
why are cysts radiolucent
because they are cavities containing non-mineralised tissue
when might a cyst not be radiolucent
if expanding into the sinus
how would a cyst in the sinus look
radiopaque
when might a cyst be symptomatic
when they are infected
when might cysts that dont normally cause resorption in teeth result in this
if they are there for a long time
what internal structure might we see if a cyst has been present for a long time
internal dystrophic calcification
what is dystrophic calcification
faint wispy radiopacities inside the cyst
which aspect of the articular disc is thicker
posterior
where do the nerve endings of the TMJ lie
posterior attachment of the retrodistal tissues
what will a DPT show for the TMJ
lateral view of the condylar head
what will a PA mandible show for the TMJ
postero-antero view of the condylar head
what will the reverse townes show
anterio-posterior view of the mandible
what technique is a reverse townes taken with
mouth open technique
what will a lateral oblique show for the TMJ
lateral view of the condylar head
what is a lateral oblique an alternative to for the TMJ
DPT
should you do a DPT for a TMJ assessment ?
no
why should you not do a DPT for a TMJ assessment
most pain associated with the TMJ is myofascial in origin rather than related to the articular disc
when would a DPT for the TMJ be indicated
- recent trauma
- change in occlusion
- mandibular shift on open/close
- sensory/motor alterations
- change in range of movement
what is the first line of imaging to visualise the TMJ for trauma
PDT and PA mandible at 90 degrees to each other
what image is taken for the TMJ if DPT/PA mandible is not sufficient
CBCT
what was previously taken when DPT/PA mandible was not sufficient, before CBCT was readily available
reverse townes
what imgaes of the TMJ would be takenn for a pt with low glasgow coma scale?
straight to CT in A&E
what is superimposed over the anterior teeth in a PA mandible
cervical spine
why is the superimposition over the anterior teeth in a PA mandible significant?
will make very difficult to diagnose fractures in that area via this view
what does increased radiopacity around the condylar head suggest
fracture
what view would be taken to assess bony changes of the condyles and articular eminences
CBCT
what is CBCT best used for in related to TMJ and why
degenerative bone disease as no soft tissue definition
how does the radiation dose of CT differ from CBCT
increased
how does traditional CT differ from CBCT
can visualise soft tissue and bone
what is traditional CT best used for in relation to TMJ/ imaging of the head and neck
neoplastic masses
what is the resolution of the CT scan dependant on
voxel size
why is CBCT better resolution and have better fine detail than CT
CT has a bigger voxel size than CBCT
how will cortical bone appear on CT
bright white
how will air appear on CT
very dark
how will cancellous bone appear on CT
grey
what radiation dose does MRI have
none
what can MRI show clearly
soft tissue and bony pathology
what is MRI really good at in relation to the TMJ
assessing the position of the articular disc
what MRI views would be taken to assess the condyle for function
opena dn closed mouth views
what two views must you check on an MRI for the position of the articular disc
-coronal
-parasagittal along axis of condyle
where does the articular disc typically displace
anteriorly and medically
how does cortical bone appear on an MRI
black
how does fatty cancellous bone appear on an MRI
white
how does the articular disc appear on an MRI
dark grey
where is the condyle expected to appear on an open mouth MRI view
directly below the narrowest portion of the articular disc
what clinical sign would indicate anterior disc displacement with reduction
reciprocal clicks on opening when the disc is recaptured
where would the articular disc lie when the mouth is closed if there is anterior disc displacement with reduction
anteriorly
when might TMJ problems result in limited opening for the pt
anterior disc displacement without reduction
what are the symptoms of anterior disc displacement without reduction
- limited mouth opening
- pain
why is there pain with anterior disc displacement without reduction
the retrodiscal tissues are being stretched
where does the disc sit when the mouht is open and closed in anterior disc displacement without reduction
anteriorly for both
when might there be anterior disc displacement and bony arthritic changes
if there is chronic anterior disc displacement
what does anterior disc displacement without reduction cause
loss of joint space and associated bony arthritis affecting the condylar head
what is loss of cortical bone in TMJ imaging suggestive of
degenerative changes
what does a “point” at the condylar head suggest
osteophyte
what will chronic degenerative changes of the TMJ also result in
shrivelled up articular disc in the wrong place - non-functional disc
what imaging is used for the TMJ within nuclear medicine
SPECT
what does SPECT stand for
single photon emission CT
what is injected in SPECT
IV technetium 99 metastable (radioisotope)
when is SPECT used for the TMJ
is condyler hyperplasia
what is the normal range of SPECT
45-55%
what will SPECT show
hotspots of metabolic activity
what sensitivity/ specificity does SPECT have
highly sensitive, poorly specific
what does SPECT struggle to tell us
the cause of the increased metabolic activity
what can hotspots on SPECT be due to
- pathology
- increased growth
- inflammation
how is the cause of increased metabolic activity determined when using SPECT
help of other imaging and clinical presentation
what is the Tx for condylar hyperplasia
- resect hyperplastic tissue
- distraction osteogenesis to form new condylar head
what is arthrography an alternative to
MRI
what are contraindications to arthrography
- claustrophobia
- implanted devices
what is arthrography good at
assessment of soft tissues
what purposes can arthrography be used for
- diagnostic
- therapeutic
what might be injected into joint space to releive TMD symptoms
steroid
why is it important to inject the contrast for arthrography into the lower TMJ space first
if any perforation in the disc then the contrast will leak into upper compartment
what guidance is arthrography done under
fluoroscopic guidance
when would minor salivary glands be visible on the radiograph
only if pathological
why would we image salivary glands
- obstruction
- dry mouth
- swelling
what migth cause obstruction of salivary glands
- mucous plugs
- salivary stones
- neoplasia
why would you take images for dry mouth
to exclude sjorgens
what can swelling of salivary glands be secondary to
- obstruction
- bacterial/ viral infection
- neoplastic growths
what would be the two forms of first line imaging for obstructive gland disease
- plain film radiographs
- ultrasound
what would be second line imaging for obstructive gland disease
sialography
what would influence your decision to take plain film radiographs of obstructive gland disease in the first instance
location
when would imagine of obstructive gland disease start with ultrasound
hospital setting
what radiograph would you take for submandibular stones
lower true occlusal
what is good for assessing stones within the submandibular gland itself and to exclude teeth as the cause of pain
DPT
what is the genue
bend of the submandibular gland
what will nay siolith wihint the FOM anterior to the genue be on a raidography?
superimposed over the body of the mandible
what would you do if the visualisation of a siolith is difficult on a adPT
supplement with a lower true occlusal
which radiography gives better visualisation to the submandibular region
lateral oblique
what does a lateral oblqiue give better visualisation of the submandibular gland
angulation prevents the superimposition of the mandible over the submandibular gland
why are PA mandibles and true laterals not very useful in imaging salivary glands
superimposition of anatomical structures
why are ill defined radiolucent regions in salivary stones seen on a radiographs
peripheral laydown of Ca ions deposits over time
name 6 other calcifications that can be mistaken for salivary stones
- tonsilloliths
- phleboliths
- calcified plaques
- normal anatomy
- elongated calcified stylohyoid ligament
- calcified lymph nodes
where will tonsil stones appear on a DPT radiograph
superimposed over the ascending ramus
what are phleboliths
calcifications within venous structures
what appearance do phleboliths have on a radiograph
target appearance
which artery can atheromas appear in on a DPT
carotid
where would atheroma in the carotid artery appear on a DPT
level of bifurcation of the common carotid artery and C3/4 vertebrae
lateral to hyoid bone
where would a calcified elongated stylohyoid ligament appear on a DPT
inferiorly/ medically to hyoid bone
what will calcified lymph nodes look like on a radiograph
cauliflower like masses
what does a pt usually have a history of if they have calcified lymph nodes
- TB
- cat-scratch disease
- sarcoidosis
- malignancy
what is ultrasound
non-ionising radiation technique
how does ultrasound work
creates images through high frequency sound waves
can ultrasound be heard
no
do ultrasound have a long or short wavelength
short
is ultrasound transmittable through air
no
what does ultrasound need to help the waves get into the tissues
coupling agent - gel
how does the ultrasound transducer create waves
electric current passed through crystals on transducer surface
when do the ultrasound waves return back ti the transducer
when boundaries between different tissues are met
how is the image produced in ultrasound
speed of sound and time are used to calculate tissue depths to create image
what does hypoechoic mean
dark on ultrasound
what does hyperechoic mean
light/ bright on ultrasound
what does homogeneous mean on ultrasound
uniform density
what does heterogenous mean on ultrasound
mixed density
what is ultrasound good for salivary glands
- they are superficially placed
- can assess all anatomy
- can be used with sialogogue
which part of which salivary gland is not superficially placed
deep lobe of the parotid
where does the deep lobe of the parotid lie
deep to the ramus
what anatomy can ultrasound assess in a salivary gland
- parenchymal pattern
- vascularity
- ductal dilation
- neoplastic masses
give an example of a sialogogue that could help in ultrasound assessment
citric acid
why are sialogogues used with ultrasound imaging of salivary glands
allow better visualisation of dilated duct s
what is a key point to reading ultrasounds
anatomy is the opposite of what we expect to see
what are the two most common cause of obstructive salivary gland disease
stone or mucous plug
what % of siloliths are associated with submandibular gland
80%
what % of submandibular sialoliths are radiopaque
80%
what outline do salivary stones have on an ultrasound
hyperechoic
why do salivary stones hvae a hyperechoic outline on ultrasound
more of the sound waves are absorbed there
why might we take a sialography
- to rule out any ductal narrowings
- planning for access for intervantional procedures
what is sialography
injection of iodinated contrast into duct to look for obstruction
what is sialography done with
DPT , PA mandible or fluoroscopic approach
is LA required for sialography
no
what volume of contrast is injected in sialography
0.8-1.5ml
name 2 interventional procedures that may be done for obstructive gland disease
- basket retrieval
- balloon dilation of ductal structures
name 5 risks of sialography
- discomfort
- swelling
- infection
- stone could move
- allergy to contrast
what would be an alternative for sialography if the pt has contrast allergy
MRI
what would be a contraindication to sialography
any sign of infection
why is infection a contraindication to sialography
could result in bacterial ascending infection
what is a advantage to fluoroscopic sialography
can watch the contras enter the ductal system in real time
what is a disadvantage to fluoroscopic sialography
increased radiation dose to pt
what must staff wear during fluoroscopic sialography
lead aprons
what does subtractive approach allow for in fluoroscopic sialography
only the contrast is seen
when if fluoroscopic sialography useful
if doing minimally invasive salivary gland interventions
why is fluoroscopic sialography useful in basket retrieval
can see the exact location in relation to the duct
what are the 3 phases of sialography
- pre-contrast
- contrast/filling phase
- emptying phase
what is the pre-contrast phase of sialography used as
base line
what is the contrast/ filling phase of sialography
contrast is injected via cannula
how long does the emptying phase occur after removing the cannula in sialography
5 mins
what base does the contrast used in sialography have
aqueous
why is it important that the contrast in has sialography water base rather than oil
easier to excrete and less likely to cause reactions
describe how sialography contrast would become extravasated
perforation of ductal wall and contrast ends up in adjacent tissues
what normal appearance does a parotid gland have under sialography
tree in winter
why does parotid gland have a tree in winter appearance when under sialography
thick duct followed by narrowing of second and third ductal structures
what appearance does the submandibular gland have when under sialography
bush in winter
what might be seen on sialography if there are acinar changes
snow storm appearnace
what sialography changes are consistent with chronic sialdenitis or sjogrens syndrome
globular acinar
what would you see under sialography when there is chronic sialdenitis or sjogrens
globular acinar changes
what 2 images should be taken in sialography
- one with contrast in place
- one during emptying phase with time delay
why should there be a time delay in taking the emptying phase radiography in sialography
allows the gland time to produce saliva to excrete contrast
what would we know if there is almost complete removal of the contrast during sialography but we know there is an obstruction
obstruction is mobile
what may cause us to think there is an obstruction during sialography when there isnt
air bubbles
what will obscure fine detail during sialography
overfilling
what will cause the pt discomfort when doing sialography
overfilling on contrast
what should you do instead of sialography if the pt has an iodine allergy
MRI sialography
what is an option of surgical r
