radiology Flashcards
how do most common pathologies appear radiographically?
radiolucent
why are most pathologies radiolucent
resorption of bone
decreased mineralisation of bone
decreased thickness of bone
what is a cyst
a pathological cavity having fluid, semi-fluid or gaseous contetns & which is not created by the accumulation of pus
what is the most common pathological radiolucency
jaw cysts
what are the 2 types of odontogenic cysts
developmental
inflammatory
name 3 developemental odontogenic cysts
dentigerous
keratocyst
lateral periodontal
name 2 inflammatory odontogenic cysts
radicular
inflammatory collateral
name 2 inflammatory collateral cysts
paradental
buccal bifurcation
name 2 non-odontogenic bone cysts
solitary
aneurysmal
what is the first step in differential diagnosis of any lesion?
is it:
anatomical
artefactual
pathological
how are radiolucencies described
site
size
shape
margins
internal structure
effect on adjacent anatomy
number
how is site describes?
where is it? - alveolar bone, basal bone etc
is there a notable relationship with another structure?
what is its position relative to particular structures?
if a lesion if below the inferior alveolar canal is it likely to be odontogenic?
no
if a lesion is entirely above the maxillary sinus floor is it likely to be odontogenic
no
how is size measured and desribed
dimensions - mesio-distally and supero-inferiorly
boundaries - which teeth etc
how can more accurate size of lesion be determined
CBCT
how are margins of lesions described
well-defined & corticated or non-corticated
poorly defined and blending into adjacent normal anatomy or ragged or moth eaten
what does a corticated lesion indicate
benign
what does a moth eaten lesion indicate
malignancy
how is internal structure of lesions described
entirely radiolucent
radiolucent with some internal radiopacity
radiopaque
how do you desribe internal radiopacities
amount - scant, multiple, dispersed
bony septae - thin/coarse, prominent/faint, straight/curved
particular structure - enamel and dentine radiodensity
give 8 potential causes of periapical radiolucency
periapical granuloma
periapical abscess
radicular cyst
perio-endo lesion
cemento-osseous dysplasia
surgical defect
fibrous healing defect
ameloblastoma
name 8 cysts and pathologies causing cyst-like radiolucencies
radicular cyst
dentigerous cyst
inflammatory collateral cyst
odontogenic keratocyst
ameloblastoma
nasopalatine duct cyst
solitary bone cyst
stafne cavity
what is the most common pathological radiolucency in jaw bones
radicular cyst
what is a radicular cyst ALWAYS associated with
non-vital tooth
describe the formation of radicular cyst
pulpal necrosis - periapical periodontitis - periapical granuloma - radiculuar cyst
when would cysts be painful
when they becoome infected
what is the difference between radicular cysts and periapical granulomas
radicular cysts bigger
>15mm 66% radicular
what is a residual cyst
when radicular cyst persists after loss of tooth (or after tooth is successfully RCTd)
what is a lateral radicular cyst
radicular cyst associated with an accessory canal
what causes dentigerous cysts
cystic change of dental follicle
what teeth are most associated with dentigerous cysts
lower 8s, upper 3s
when are dentigerous cysts most common (age)
2nd-4th decade
when would you consider dentigerous cysts rather than enlarged follicle
consider if follicular space is >5mm
assume cyst if >10mm or asymmetrical
what are inflammatory collateral cysts associated with
vital teeth
where do buccal bifurcation cysts occur
buccal aspect of lower 6s
where do paradental cysts occur
distal aspect of partially erupted lower 8s
what is basal cell naevus syndrome
multiple odontogenic keratocysts
multiple basal cell carcinomas
what is basal cell naevus also known as
gorlin-goltz syndrome
what is ameloblastoma
benign epithelial odontogenic tumour
what are most ameloblasotmas radiographically
multicystic - 85-90%
what are the 3 main histological types of ameloblastoma
follicular
plexiform
desmoplastic
what is odontogenic myxoma
benign mesenchymal odontogenic tumour
do odontogenic myxoma have high recurrence rate?
yea
how do odontogenic myxomas present radiographically
premolar/molar region mandible
multilocular and scalloped
soap bubble appearance
where do nasopalatine duct cysts arise from
nasopalatine duct epithelial remnants
what would a pt notice with nasopalatine duct cyst
salty taste
whats another name for nasopalatine duct cyts
incisive canal cyst
where are nasopalatine duct cysts always founf
anterior maxilla in midline
how are nasopalatine duct cysts usually descirbed from radiographs
unilocular, rounded and symmetrical
what are 3 types of solitary bone cyst
simple
traumatic
haemorrhagc
where are solitary bone cysts normally found
posterior mandible
what is a stafne cavity
depression in the bone - cortical bone preserved
what does a stafne defect contain
salivary or fatty tissue
where are stafne defect normally found
mandible - often body but can be ramus
what is the radiographic appearance of stafne defects
unilocular
rounded
well defined and corticated
what can happen radiographically to infceted cysts
can lose their well-defined, corticated margins
can mimic maliganancy
what are clinical features of secondary infection
pain
soft-tissue swelling/redness/hotness
purulent exudate
what are clinical signs and symptoms for malignancy in oral cavity
non healing socket
non healing ulcer
unusually mobile tooth
swelling/exophytic mass
lymphadenopathy
pain/numbness
what are non clincial signs of malignancy
weight loss
night sweats
problems moving tongue
dysphagia
dysphonia
loss of hearing
pathological fractuer
what are radiographic signs of malignancy
moth eaten bone
non healing sockets
floating teeth
unusual perio bone loss
is a slow growing lesion more likely to be malignant or benign
benign
what may lack of cortification represent?
healing lesion
superimposed infection
what is a bad prognostic sign radiographically?
moth eaten radiolucent bone with no margin
what is the difference between benign and malignant effects on other structures
benign - displace structures
malignant - destroy structures
What effect do malignancies have on teeth?
Spiking root resorption
Widening of PDL space
Generalised loss of lamina dura
What are risk factors for osteosarcoma?
FD
Retinoblastoma
Previous radiation
Previous primary bone cancer
Paget’s disease
Chronic osteomyelitis
What is multiple myeloma
Multi focal proliferation of plasma cells in bone marrow leading to over-production of immunoglobulins
What would a solitary multiple myeloma lesion be called
Plasmocytoma
What are radiographic features of multiple myeloma
Round/unilocular
Radiolucency
Punched out
Well-defined, not corticated
Pathological # if large
How can lymphoma present
Soft tissue lump
What is langerhans histocytosis
Proliferation of langerhans cells and eosinophilic leukocytes
What are the 3 manifestations of langerhans histocytosis
Eosinophilic granuloma
Hand-Schuller-Christian disease (mulitfocal eosiniophilic granulomas
Letterer-siwe disease
What is the radiographic appearance of langerhans histocytosis
Unilocular
Radiolucent
Punched out
Smooth outline
Floating teeth
No expansion
What cancers metastasis to bone
Lung
Prostate
Breast
Kidney
Thyroid
What are 3 differential dx fro malignancy when there’s moth eaten bone
Osteomyelitis
Osteoradionecrosis
MRONJ
Name 5 types of imaging for TMJ
Plain film
CBCT
Computed tomography (CT)
Magnetic resonance imaging (MRI)
Nuclear medicine
Name 4 plain film ways to image TMJ
Panoramic radiography
PA mandible
Reverse Townes
Lateral Oblique
When would DPT be indicated for TMJ assessment
Recent trauma
Change in occlusion
Mandibular shift
Sensory/motor alterations
Change in range of movement
What is CBCT best used for
Degenerative bone disease
What can CT visualise
Soft tissue and bone
How is TMJ disc assessed with MRI
Open and closed views
Check 2 separate views for position of disc (coronal and parasagittal view along long axis of condyle)
What is nuclear medicine name
SPECT - single photon emission CT
What is used in SPECT
Injection of IV technetium 99-meta stable (radio-isotope)
What is SPECT used for
Condylar hyperplasia
What do we imagine salivary glands for
Obstruction
Dry mouth
Swelling
Name 3 salivary gland obstructions
Mucous plugs
Salivary stones
Neoplasia
What imaging modalities can be used for salivary glands
Plain film
Ultrasound
Sialography (injection of iodinated contrast)
MRI
Nuclear medicine
What plain films can be used for salivary glands
Lower true occlusal
OPT
Lateral oblique
Why are true laterals and PA mandibles not used for salivary glands
Superimposition of anatomical structures
What other calcifications could be mistaken for sialoliths
Tonsilloliths (tonsil stones)
Phleboliths
Calcified plaques (atheromas) in carotid artery
Normal anatomy (hyoid)
Elongated/calcified stylohyoid ligament
Calcified lymph nodes
What is ultrasound
No ionising radiation
High frequency sound waves - cannot be heard audibly
Sound waves have short wave length which are not transmittable through air
How does ultrasound work
Sound waves enter body and reflect back to transducer when boundaries between different tissues are met e.grounders betweeen muscles and Salivary gland
What does hypoechoic mean
Dark
What is hyperechoic
Bright
Why is ultrasound good for salivary glands
Glands are superficially positioned
Can assess parenchymal pattern, vascularity, ductal dilatation or neoplastic masses
Can give a sialogogue to aid saliva flow to allow better visualisation of dialated ducts
What are the symptoms of obstructive disease
Prandial pain and swelling
Bad taste
Thick saliva
Dry mouth
What % of sialoliths are submandibular
80%
What is sialography
Injection of iodinated radiographic contrast into salivary duct to look for obstruction
Done worth either DPT, rotated PA mandible + lateral oblique, or Fluoroscopic approach
How many ml contrast is injected for sialography
0.8-1.5ml
What are the indications for sialography
Looking for obstruction or stricture of salivary ducts which could be leading to prandial symptoms
Planning for access for interventional procedures (basket retrieval, ballon dilation)
What are the risks of sialography
Discomfort
Swelling
Infection
Any stone could move
Allergy to contrast
What are the 3 phases of sialography
Pre-contrast
Contrast/filling phase
Emptying phase
What is the pre-contrast phase used for in sialography
Excuse other pathology which could account for symptoms e.g. odontogenic pathology
Use as a base line
What are the normal findings in sialography
Parotid - tree in winter
Submandibular - bush in winter
Acinar changes - snow storm appearance
When should images be taken for sialography
Contrast phase with cannula in place
Emptying phase with time delay
What is used as an alternative to sialography if the patient has an iodine allergy
MRI sialography
Heavy T2W scan - gets rid of all tissues apart from fluid.
What are the 4 selection criteria for stone removal
- stone must be mobile
- stone should be located within the 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
