Radiology Flashcards
What is a radiolucency on a radiograph a result of?
- resorption of the bone
- decreased mineralisation of the bone
- decreased thickness of the bone
What is a cyst?
A pathological cavity having fluid, semi-fluid or gaseous contents which is not created by the accumulation of pus.
Are jaw cysts more likely to be asymptomatic or symptomatic? Slow growing or fast growing? Indolent or destructive?
Asymptomatic
Slow growing
Indolent
Are almost all jaw cysts benign or malignant?
Benign
Name 2 classifications of jaw cysts.
Odotonogenic (derived from tooth tissue, 90%)
Non-odontogenic (not derived from tooth tissue)
Name 2 classifications of odontogenic cysts.
Developmental or inflammatory
Name 3 developmental odontogenic cysts.
- Dentigerous cyst
- Odontogenic keratocyst
- Lateral periodontal cyst
Name 2 inflammatory odontogenic cysts
1.Radical cyst (& residual cyst)
2. Inflammatory collateral cyst –> e.g paradental or buccal bifurcation cyst.
What is the first step in differential diagnosis of a radiolucency?
Confirm whether the radiolucency is anatomical, artefactual or pathological.
Name 7 different characteristics you would want to describe for a radiolucency.
- Size - where is it - is it notable to another structure?
- Shape
- Site
- Margins
- Internal structure
- Effect on adjacent anatomy
- Number
If a lesion is below the inferior alveolar canal or above the maxillary floor then what can this indicate?
These lesions are highly unlikely to be odontogenic
Name different descriptions to describe the shape of a lesion.
The locularity e.g unilocular, irregular, multilocular, pseudolocular.
Generally shape can be rounded, scalloped or irregular.
Name different descriptions to describe the margins of a radiolucent lesion.
- Well defined and corticated
- Well defined and non-corticated
- Poorly defined and blending into the adjacent normal anatomy
- Poorly defined and “ragged” or “moth eaten”
If a lesion is corticated what does that suggest about the lesion?
Suggests a benign lesion.
If a lesion appears as “moth eaten” what does this suggest about the lesion?
Suggests malignancy
What do cysts typically appear as?
Cysts are typically well-defined and corticated but can become poorly defined if infected - typically associated with clinical signs/symptoms.
State how you would describe internal structures of cysts.
Could be:
1. Entirely radiolucent - most common
2. Radiolucent with some internal radiopacity
3. Radiopaque
Can describe the amount of radiopacities e.g scant, multiple, or dispersed.
Can describe if theres bony septae in the cyst e.g thin/course/prominent/straight/curved
Can describe a particular structure e.g enamel or dentine (odontomas).
What kind of cyst is likely if the radiolucency is around the apex of a tooth?
Radicular cyst
What kind of cyst is likely if the radiolucency is adjacent to the tooth?
A lateral periodontal cyst
What kind of cyst is likely if the radiolucency surrounds the crown of the tooth?
Dentigerous cyst.
What kind of cyst is likely if the radiolucency surround the entire tooth ?
Calcifying epthelial tumour.
Name some anatomical features you would want to look at on a radiograph when assessing a lesion.
- teeth (displacement/resorption)?
- inferior alveolar nerve/maxillary sinus (compression/erosion)?
- bone (displacement/perforation of cortices)?
What would you suspect if more than 2 lesions present in a radiograph?
Suspect a syndrome causing these lesions.
What are 8 potential causes/diagnoses of a periapical radiolucency?
- Periapical granuloma
- Periapical abscess
- Radicular cyst
- Perio-endo lesion
- Cemento-osseous dysplasia (in early stage)
- Surgical defect (following peri-radicular surgery)
- Fibrous healing defect (following resolution of healing)
- Ameloblastoma occuring next to tooth.
As a periapical radiolucency can have multiple causes, the clinical signs and symptoms, the condition of the tooth and gums and the patient demographic are all important factors when diagnosing. True or false?
True
A radicular cyst is the most common pathological radiolucency in the jaw bones (excluding periapical granuloma), what % of cysts in the jaw is a radicular cyst?
70%.
Describe how a radicular cyst forms
A radicular cyst is initiated by chronic inflammation at the apex of the tooth by pulpal infection - this cyst is always associated with a non-vital tooth.
Pulpal necrosis –> periapical periodontitis–> periapical granuloma–> radicular cyst.
What is the incidence of radicular cysts?
Most common in 4th - 5th decade
Male = females
60% in maxilla, 40% mandible however can involve any non vital tooth.
What is the presentation of radicular cysts?
Often asymptomatic
May become infected which would cause pain
Typically slow growing with limited expansion
How can you differentiate between a radicular cyst and a periapical granuloma radiographically?
Difficult to differentiate radiographically. Radicular cysts are typically larger. If the radiolucency is >15mm then 2/3rds would be radicular cyst.
Describe typically a radicular cyst from a radiograph using the 8 different characteristics when diagnosing.
Site: apex of a non vital tooth
Size: Variable
Shape: unilocular and rounded
Margins: Well-defined and corticated
Internal structure: entirely radiolucent
Tooth involvement: Yes- associated root; margins continous with lamina dura
Effects: Can displace adjacent teeth/structures, long standing lesions can cause external root resorption
Number: Single (but potentially multiple if grossly carious dentition).
What is a residual cyst?
When radicular cyst persists after tooth loss (or after tooth is successfully root canal treated).
What is a lateral radicular cyst?
Radicular cyst associated with a lateral canal. Located at the side of the tooth instead at the apex.
What is a dentigerous cyst?
A developmental odontogenic cyst derived from cystic change from the dental follicle. Associated with crown from unerupted/impacted tooth e.g mandibular 3rd molar and maxillary canines.
What is the incidence of dentigerous cyst?
Second most common cyst 20%
Most common in 2nd-4th decade
Male > female
Mandible > maxilla
Describe typically a dentigerous cyst from a radiograph using the 8 different characteristics when diagnosing.
Site: around crown of unerupted tooth (often symmetrical encapsulation of crown but may expand unilaterally).
Size: variable (e.g can involve entire ramus of mandible)
Shape: Unilocular and rounded but can be scalloped if large
Margins: well defined and corticated
Internal structure: entirely radiolucent
Tooth involvement: Yes- continuous with CEJ (but large cysts can begin to envelope root as well)
Effects: Displacement of tooth; potential external root resorption of adjacent teeth; variable displacement of adjacent structures
Number: Single
How would you differentiate between a dentigerous cyst and a dental follicle?
Consider cyst if follicular space is > 5mm
Measure from surface of crown to edge of follicle
Normal follicular space is typically 2-3mm
Assume cyst if >10mm
Consider cyst if radiolucency is assymetrical
What are the 2 types of inflammatory collateral cyst?
- Buccal bifurcation cyst (typically occurs at buccal aspect of mandibular first molar)
- Paradental cyst (typically occurs at distal aspect of partially-erupted mandibular third molar).
What is inflammatory odontogenic cysts?
Associated with a vital tooth
2-7% odontogenic cysts
Most common in 1st-2nd decades
Asymptomatic but can cause swelling
Describe typically a inflammatory collateral cyst from a radiograph using the 8 different characteristics when diagnosing.
Site: buccal or distal to furcation area of permanent molar (mandible > maxilla)
Size: <25mm
Shape: unilocular and rounded
Margins: well-defined and corticated
Internal structure: entirely radiolucent
Tooth involvement: yes - involves furcation
Effects: tilting of tooth; cortical displacement
Number: Single or bilateral
What is an odontogenic keratocyst?
A developmental odontogenic cyst
No specific relationship to teeth
Can grow large before clinically evident
High recurrence rates
What is the incidence of odontogenic keratocyst?
Rare
Most common in 2nd - 3rd decades
Male>Female
Mandible >Maxilla (3:1)
Posterior > anterior
Describe typically an odontogenic keratocyst from a radiograph using the 8 different characteristics when diagnosing.
Site: commonly posterior mandible
Size: Variable but can get very large
Shape: Pseudolocular or multilocular; scalloped
Margins: Well defined and corticated
Internal structure: entirely radiolucent
Tooth involvement: no (but often next to one)
Effects: marked expansion within trabecular bone in contrast to limited displacement of cortices; minimal displacement of adjacent teeth; rare external root resorption
Number: single (but can be multiple if syndromic)
What is basal cell syndrome also known as?
Gorlin-Goltz syndrome or bifid rib syndrome
What does basal cell syndrome present as?
Multiple odontogenic keratocysts
Multiple basal cell carcinomas
Palmar and plantar pitting
Calcification of intracranial dura mater
What is an ameloblastoma ?
Benign epithelial odontogenic tumour
Locally destructive but slow growing
Typically painless
High recurrence rates
What is the incidence of amelobastomas?
Rare (but most common odontogenic tumour)
Most common in 4th - 6th decades
80% occur in the posterior mandible
Males > females
What is the different types of ameloblastomas?
Radiological: Multicystic (85-90%) or unicystic (more common in younger patients with lower recurrence risk)
Histological: Follicular, plexiform, desmoplastic, several other less common types.
What is the different types of ameloblastomas?
Radiological: Multicystic (85-90%) or unicystic (more common in younger patients with lower recurrence risk)
Histological: Follicular, plexiform, desmoplastic, several other less common types.
Describe typically an ameloblastoma from a radiograph using the 8 different characteristics when diagnosing.
Site: commonly in posterior mandible
Size: Any shape
Shape: Unilocular or multilocular (multilocular lesions may have coarse septae and/or soap bubble appearance
Margins: Well defined and corticated
Internal structure: radiolucent (but rare radiopaque variant)
Tooth involvement: no
Effects: growth not constrained by cortices; thinning of cortices; can cause “knife edge” external root resorption
Number: single
What is an odontogenic myxoma?
Benign mesenchymal odontogenic tumour with a high recurrence rate
What is the incidence of odontogenic myxoma?
Rare (3-6% of odontogenic tumours)
Most common in 3rd decade
F=M
Mandible>maxilla
Describe typically an odontogenic myxoma from a radiograph using the 8 different characteristics when diagnosing.
Site: often premolar/molar region of mandible
Size: Any size
Shape: Multilocular and scalloped (may have coarse septae and/or soap bubble appearance. Small lesions can be unilocular
Margins: Well defined; thin corticated margin
Internal structure: radiolucent
Tooth involvement: no
Effects: initially extends into inter-radicular spaces but larger lesions displace teeth; initial expansion within trabecular bone before displacing cortices
Number: Single
What is the nasopalatine duct cyst?
Developmental non-odontogenic cyst. Arises from nasopalatine duct epithelial remnants. Occurs in anterior maxilla. Often asymptomatic but patient may notice “salty” discharge
What is the incidence of nasopalatine duct cyst?
Most common non-odontogenic cyst (in jaws)
Affects 1% of population
Most common in 4th - 6th decades
M>F
Describe typically a nasopalatine duct cyst from a radiograph using the 8 different characteristics when diagnosing.
Site: always anterior maxilla in midline
Size: usually between 6mm and 30mm in diameter.
Shape: Typically unilocular, rounded and symmetrical (but can be pseudolocular & lop sided. May appear “heart-shaped” due to super-imposed anterior nasal spine
Margins: well-defined and cortical
Internal structure: no, but inevitably next to incisor roots.
Effects: displacement of incisors; palatal expansion
Number: single
How can you differentiate between a nasopalatine duct cyst and an incisive fossa?
Incisive fossa may or may not be visible on radiographs.
Midline oval shaped radiolucency
Typically not visibly corticated on radiographs
In the absence of clinical issues, consider the transverse diameter
<6mm assume incisive fossa
6-10mm continue monitoring
>10mm suspect cyst
What is a solitary bone cyst?
Non-odontogenic lesion - technically not classified as a cyst. Almost always no symptoms or clinical signs. Aka simple bone cyst/traumatic/haemhorrhagic bone cyst
What is the incidence of a solitary bone cyst?
Rare
Most common in 2nd decade
Males>Females
Mandible>Maxilla
Can occur in association with other bone pathology e.g fibro-osseous lesions
Describe typically a solitary bone cyst from a radiograph using the 8 different characteristics when diagnosing.
Site: Typically posterior mandible
Size: Typically <30mm approximately
Shape: unilocular or pseudolocular; scalloped (may extend into inter-radicular spaces with “finger-like” projections
Margins: variable
Internal structure: entirely radiolucent
Tooth involvement: no
Effects: Typically none; rare displacement of teeth
Number: single
What is the Stafnes defect?
Not a cyst but commonly mistaken as one. Actually a depression in the bone - cortical bone preserved. Contains salivary or fatty tissue. Asymptomatic
What is the incidence of Stafnes defect?
Rare
Common in the 5-th 6th decades
Thought to be linked to salivary gland
Describe typically Stafnes Defect from a radiograph using the 8 different characteristics when diagnosing.
Site: Mandible (often body but can be ramus)
Size: Usually <20mm
Shape: Unilocular and rounded
Margins: Well defined and corticated
Internal Structure: Entirely radiolucent
Tooth involvement: no
Effects: Typically none; rare displacement of adjacent structures
Number: Single
What can happen radiographically if a cyst becomes infected?
Can lose their well defined, corticated margins. This can mimic features of malignancy.
Most jaw lesions will inevitably be near a tooth, however does this mean the lesion is associated with that tooth?
No
Do cysts always follow the typical radiographic appearance?
No
Name some clinical signs and symptoms of oral cancer.
Leukoplakia/erythroplakia/erythroleukoplakia
Non healing socket
Non-healing ulcer
Unusually mobile tooth (no hx of perio)
Swelling/Exophytic mass
Lymphadenopathy
Pain/numbness
What are other signs and symptoms to consider for malignancy?
Weight loss “B symptom”
Night sweats “B symptom”
Problems moving tongue
Dysphagia (difficulty swallowing)
Dysphonia (hoarseness in voice)
Loss of hearing (more advanced disease)
Pathological fracture
What is some radiographic signs of malignancy?
Moth eaten bone
Non healing sockets
Floating teeth (teeth with no alveolar bone support)
Unusual perio bone loss (localised to specific area)
Spiculated periosteal reaction - “sunburst” reaction
Unusual uniform widening of the periodontal ligament space
Generalised loss of lamina dura
Loss of bony outlines for anatomical features e.g walls of antrum, corticated margins of IDC.
Thinning of cortico-endosteal margin
Spiking root resorption
What would a lack of corticated lesion suggest
- Healing lesion (from prev biopsy)
- Superimposed infection
- Moth eaten radiolucent bone with no infection indicates bad prognostic sign
What effects do malignant lesions have on anatomical structures as opposed to benign lesions?
- Benign lesions will displace anatomical features due to slow growth
- Malignant lesions will destroy anatomical structures
know what is normal, particularly for the maxillary sinus.
What is osteosarcoma and what are its risk factors?
Osteosarcoma is a type of of bone cancer. Typically young adults (typically 30’s)
Risk Factors:
- Fibrous dysplasia
- Retinoblastoma
- Previous exposure to radiation
- Previous primary bone cancer
- Pagets Diseae
- Chronic Osteomyelitis
What is the most common symptoms of osteosarcoma and how often does this occur in the head and neck?
Symptoms: Persistent pain, Oedema, Parasthesia
10% Occur in the head and neck
What is multiple myeloma?
Multifocal proliferation of plasma cells in bone marrow leading to over-production of immunoglobulins.
Typically middle aged adults
What is a solitary lesion of multiple myeloma called?
Plasmocytoma however multiple lesions is called multiple myeloma.
What is radiographic features of multiple myeloma?
Round/unilocular
Radiolucent
Punched out
Well defined, not corticated
Large lesions can lead to pathological fracture
If multi-focal can affect all skeleton (skeletal survey)
What is lymphoma?
Cancer that begins in the cells of the lymph system
A group of lymphoproliferative diseases
Typically B cell lymphoma
Can present initially as a soft tissue lump
What is langerhans histiocytosis?
A rare condition
Proliferation of the langerhan cells and eosinophillic leucocytes
What are the 3 manifestations of langerhans histiocytosis?
- Eosinophillic granuloma (solitary lesion, typically affects adolescents/young patients)
- Hand-Schuller-Christian disease (multifocal eosinophillic granuloma) - chronic and widespread, begins in childhood and may not fully develop until early adulthood
- Letterer-Siwe disease (Widespread disease, affecting children under 3 years old).
What is the radiographic features of langerhans histiocytosis?
- Unilocular
- Radiolucent
- Punched out
- Smooth outline
- Floating teeth
- No expansion
Malignancy in the facial bones can be secondary to primary cancer elsewhere in the body. Name 5 other body parts that primary cancers can metastasise from.
Lung
Breast
Prostate
Kidney
Thyroid
What typically do these appear as and what is the exception to breast and prostate metastasis?
Typically radiolucent uncorticated and moth eaten
Breast and prostate can appear as schlerotic and osteogenic
Can you tell the difference between a primary and secondary malignancy on a radiograph?
No
What are some differential diagnosis for malignancy on a plain film radiograph
Moth eaten bone could be osteomyelitis, osteoradionecrosis, MRONJ
Key is clinical and medical history, e.g patient not had radiotherapy previously can not get osteoradionecrosis.
What kind of radiography can you the TMJ?
Plain film (OPT, PA mandible, reverse Townes, lateral obliques)
Cone Beam CT
Computed Tomography (CT)
Magnetic Resonance Imaging (MRI)
Nuclear Medicine
Should you do an OPT for a TMJ assessment?
Faculty of General Dental Practitioners selection criteria for radiography say no unless:
- recent trauma
- change in occlusion
- mandibular shift
- sensory/motor alterations
- change in range of movement
What are the 2 radiographs of choice for initial diagnosis of TMJ if trauma?
- OPT
- PA mandible
Reverse Townes rarely done
What is computed tomography?
Radiography where you can visualise soft tissue and bone therefore better for neoplastic masses. Has an increased dose of radiation compared to CBCT. Dependent on voxel size CBCT may have better resolution.
What is an MRI?
Gold standard imaging
No radiation dose
Soft tissue and bony pathology
Good for assessing articular disc position
- open and closed views
- must check two separate views for position of disc
- disc typically does anterior and medially
What is SPECT Nuclear Medicine?
Single Photon Emission CT
Injection of IV Technetium-99-metastable isotope