Radiology Flashcards
1
Q
What is a radiolucency on a radiograph a result of?
A
- resorption of the bone
- decreased mineralisation of the bone
- decreased thickness of the bone
2
Q
What is a cyst?
A
A pathological cavity having fluid, semi-fluid or gaseous contents which is not created by the accumulation of pus.
3
Q
Are jaw cysts more likely to be asymptomatic or symptomatic? Slow growing or fast growing? Indolent or destructive?
A
Asymptomatic
Slow growing
Indolent
4
Q
Are almost all jaw cysts benign or malignant?
A
Benign
5
Q
Name 2 classifications of jaw cysts.
A
Odotonogenic (derived from tooth tissue, 90%)
Non-odontogenic (not derived from tooth tissue)
6
Q
Name 2 classifications of odontogenic cysts.
A
Developmental or inflammatory
7
Q
Name 3 developmental odontogenic cysts.
A
- Dentigerous cyst
- Odontogenic keratocyst
- Lateral periodontal cyst
8
Q
Name 2 inflammatory odontogenic cysts
A
1.Radical cyst (& residual cyst)
2. Inflammatory collateral cyst –> e.g paradental or buccal bifurcation cyst.
9
Q
What is the first step in differential diagnosis of a radiolucency?
A
Confirm whether the radiolucency is anatomical, artefactual or pathological.
10
Q
Name 7 different characteristics you would want to describe for a radiolucency.
A
- Size - where is it - is it notable to another structure?
- Shape
- Site
- Margins
- Internal structure
- Effect on adjacent anatomy
- Number
11
Q
If a lesion is below the inferior alveolar canal or above the maxillary floor then what can this indicate?
A
These lesions are highly unlikely to be odontogenic
12
Q
Name different descriptions to describe the shape of a lesion.
A
The locularity e.g unilocular, irregular, multilocular, pseudolocular.
Generally shape can be rounded, scalloped or irregular.
13
Q
Name different descriptions to describe the margins of a radiolucent lesion.
A
- 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”
14
Q
If a lesion is corticated what does that suggest about the lesion?
A
Suggests a benign lesion.
15
Q
If a lesion appears as “moth eaten” what does this suggest about the lesion?
A
Suggests malignancy
16
Q
What do cysts typically appear as?
A
Cysts are typically well-defined and corticated but can become poorly defined if infected - typically associated with clinical signs/symptoms.
17
Q
State how you would describe internal structures of cysts.
A
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).
18
Q
What kind of cyst is likely if the radiolucency is around the apex of a tooth?
A
Radicular cyst
19
Q
What kind of cyst is likely if the radiolucency is adjacent to the tooth?
A
A lateral periodontal cyst
20
Q
What kind of cyst is likely if the radiolucency surrounds the crown of the tooth?
A
Dentigerous cyst.
21
Q
What kind of cyst is likely if the radiolucency surround the entire tooth ?
A
Calcifying epthelial tumour.
22
Q
Name some anatomical features you would want to look at on a radiograph when assessing a lesion.
A
- teeth (displacement/resorption)?
- inferior alveolar nerve/maxillary sinus (compression/erosion)?
- bone (displacement/perforation of cortices)?
23
Q
What would you suspect if more than 2 lesions present in a radiograph?
A
Suspect a syndrome causing these lesions.
24
Q
What are 8 potential causes/diagnoses of a periapical radiolucency?
A
- 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.
25
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
26
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%.
27
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.
28
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.
29
What is the presentation of radicular cysts?
Often asymptomatic
May become infected which would cause pain
Typically slow growing with limited expansion
30
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.
31
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).
32
What is a residual cyst?
When radicular cyst persists after tooth loss (or after tooth is successfully root canal treated).
33
What is a lateral radicular cyst?
Radicular cyst associated with a lateral canal. Located at the side of the tooth instead at the apex.
34
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.
35
What is the incidence of dentigerous cyst?
Second most common cyst 20%
Most common in 2nd-4th decade
Male > female
Mandible > maxilla
36
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
37
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
38
What are the 2 types of inflammatory collateral cyst?
1. Buccal bifurcation cyst (typically occurs at buccal aspect of mandibular first molar)
2. Paradental cyst (typically occurs at distal aspect of partially-erupted mandibular third molar).
39
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
40
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
41
What is an odontogenic keratocyst?
A developmental odontogenic cyst
No specific relationship to teeth
Can grow large before clinically evident
High recurrence rates
42
What is the incidence of odontogenic keratocyst?
Rare
Most common in 2nd - 3rd decades
Male>Female
Mandible >Maxilla (3:1)
Posterior > anterior
43
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)
44
What is basal cell syndrome also known as?
Gorlin-Goltz syndrome or bifid rib syndrome
45
What does basal cell syndrome present as?
Multiple odontogenic keratocysts
Multiple basal cell carcinomas
Palmar and plantar pitting
Calcification of intracranial dura mater
46
What is an ameloblastoma ?
Benign epithelial odontogenic tumour
Locally destructive but slow growing
Typically painless
High recurrence rates
47
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
48
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.
48
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.
49
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
50
What is an odontogenic myxoma?
Benign mesenchymal odontogenic tumour with a high recurrence rate
51
What is the incidence of odontogenic myxoma?
Rare (3-6% of odontogenic tumours)
Most common in 3rd decade
F=M
Mandible>maxilla
52
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
53
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
54
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
55
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
56
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
57
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
58
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
59
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
60
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
61
What is the incidence of Stafnes defect?
Rare
Common in the 5-th 6th decades
Thought to be linked to salivary gland
62
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
63
What can happen radiographically if a cyst becomes infected?
Can lose their well defined, corticated margins. This can mimic features of malignancy.
64
Most jaw lesions will inevitably be near a tooth, however does this mean the lesion is associated with that tooth?
No
65
Do cysts always follow the typical radiographic appearance?
No
66
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
67
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
68
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
69
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
70
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*.
71
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
72
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
73
What is multiple myeloma?
Multifocal proliferation of plasma cells in bone marrow leading to over-production of immunoglobulins.
Typically middle aged adults
74
What is a solitary lesion of multiple myeloma called?
Plasmocytoma however multiple lesions is called multiple myeloma.
75
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)
76
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
77
What is langerhans histiocytosis?
A rare condition
Proliferation of the langerhan cells and eosinophillic leucocytes
78
What are the 3 manifestations of langerhans histiocytosis?
1. Eosinophillic granuloma (solitary lesion, typically affects adolescents/young patients)
2. Hand-Schuller-Christian disease (multifocal eosinophillic granuloma) - chronic and widespread, begins in childhood and may not fully develop until early adulthood
3. Letterer-Siwe disease (Widespread disease, affecting children under 3 years old).
79
What is the radiographic features of langerhans histiocytosis?
- Unilocular
- Radiolucent
- Punched out
- Smooth outline
- Floating teeth
- No expansion
80
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
81
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
82
Can you tell the difference between a primary and secondary malignancy on a radiograph?
No
83
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*.
84
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
85
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
86
What are the 2 radiographs of choice for initial diagnosis of TMJ if trauma?
- OPT
- PA mandible
*Reverse Townes rarely done*
87
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.
88
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
89
What is SPECT Nuclear Medicine?
Single Photon Emission CT
Injection of IV Technetium-99-metastable isotope
90
What is the half life of SPECT?
6.5 hours
91
In what diagnosis is it useful to use SPECT?
Condylar Hyperplasia
92
Is SPECT highly specific in radiography?
No - highly sensitive but not specific.
93
What is arthrology?
Invasive method and can be used for diagnostic and therapeutic purposes (e.g injection of steroids into joint space)
Alternative imaging if MRI not feasible e.g if pt claustrophobic
Assessment of soft tissues - specifically articular disc
Inject iodine into joint space (lower joint space first)
Done under fluoroscopic guidance so can see bony anatomy
If contrast leaks from lower joint space to upper joint space a disc perforation is present.
94
What is TMJ disc displacement with reduction?
Articular disc will sit in an anterior position in a closed mouth and a normal positioning on mouth opening hence when the patient opens the disc "clicks" back into the normal position.
95
What is TMJ disc displacement without reduction?
Limitation on opening and pain as the retro disc tissues have been stretched. Articular disc still sits anteriorly despite opening of the jaw.
96
What muscle does the parotid gland sit over?
Masseter
97
What anatomical structures does the parotid duct go through?
Across the masster, through the buccal fat pad and pierces the buccinator muscle into the duct orifice next to the maxillary molar.
98
What muscles do the submandibular duct go through from the gland into the floor of the mouth?
Passes between the mylohyoid and hyloglossus muscle
99
What areas in the mouth are their minor salivary glands?
hard palate, soft palate, retromolar pad, FOM
100
Why would we image the the salivary glands?
1. Obstruction e.g mucous plugs, salivary stone, neoplasia.
2. Dry mouth
3. Swelling
101
What imaging modalities can we use for look at the salivary glands?
- Plain radiographic techniques
- Ultrasound
- Injection of iodinated contrast (siolography)
- CT (Computer Tomography)
- MRI (Magnetic Resonance Imaging)
- Nuclear Medicine
102
What is the imaging protocol for salivary gland obstruction?
Begin with plain film radiography or an ultrasound, dependant on these results you can move on to sialography.
103
What are the 3 types of plain film radiography that can be used to view the salivary glands.
1. True lower occlusal
2. OPT
3. Lateral oblique
104
Why are true laterals and PA mandible not useful when imaging the salivary glands?
Have superimposition of anatomical features.
105
What are other calcifications that can be mistaken for sialoliths?
- tonsilloliths (tonsil stones)
- phleboliths
- calcified plaques (arethomas) in carotid artery
- normal anatomy (hyoid bone)
- Elongated/calcified styloid ligament
-Calcified lymph nodes
106
Where would you see tonsilloliths on a OPT?
Calcifications on the ascending ramus
107
What is a phlebolith?
Calcification in venous structures
108
What would calcification of lymph nodes typically have a history of?
Tuberculosis, sarcoidosis, catscratch disease or malignancy.
109
What is an ultrasound?
Radiography imaging with no ionising radiation. High frequency sound waves that cannot be heard audibly. Sound waves have short wave length which are not transmittable through air. Require coupling agent to help sound waves to get into the tissues.
110
What is an ultrasound transducer?
Transducer emits and detects sound waves/echoes. Creates sound waves when electronic current is given to crystals on the transducer surface. Sound waves enter the body and reflect back to transducer when boundaries between different tissues are met. Using speed of sound and time to return to the echo, the tissue depths are calculated creating a 2D image.
111
What does hypoechoic mean?
Dark
112
What does hyperechoic mean?
Bright
113
What does homogenous mean?
Uniform density
114
What does heterogenous mean?
Mixed density
115
Why is ultrasound good for salivary glands?
- Glands are superficially positioned (apart from the deep lobe of the parotid hidden deep to the ramus). Can asesss parenchymal pattern, vascularity, ductal dilation or neoplastic masses.
- Can give a sialogogue (ie citric acid) to aid saliva flow, this will allow better visualisation of dilated ducts.
116
What symptoms do we expect from obstructive disease in salivary glands?
- "meal time symptoms"
- Prandial swelling and pain
- "rush of saliva into mouth "
- Bad taste
- Thick saliva
- Dry mouth
117
What is the aetiology of obstructive disease in salivary glands?
- Mostly caused by a saliva stone (sialolith or mucous plug)
- 80% associated with submandibular gland
- 80% submandibular stones are radiopaque
118
What is sialography?
- Injection of iodinated radiographic contrast into the salivary duct to look for obstruction. Done with either an OPT, a PA mandible and lateral oblique or fluoroscopic approach. No local anaesthetic required. Very small volume of contrast injected (typically 0.8-1.5ml).
119
What are the indications of sialography?
- Looking for obstruction or narrowing of salivary duct which could be leading meal time symptoms.
- Planning for access for interventional procedures (basket retrieval of stones or balloon dilation of ductal strictures.
120
What is the risks of sialography?
- discomfort
- swelling
- infection
- any stone could move
- allergy to contrast (very rare), MRI is alternative as no contrast used.
121
If a patient presented for a sialography with an infection- would you proceed with the sialography and why?
Do not continue as contrast can push bacteria further in
122
What is fluoroscopic sialography?
Can watch the contrast enter the ductal system in "real time". Increased radiation dose to the patient. Staff must wear lead aprons due to increased dose. Use a "C arm". Can be done by subtraction approach so only contrast is seen. Useful to using minimally invasive salivary gland interventions e.g baskets - can see exact location of basket/balloon in relation to the duct.
123
What is the first phase of sialography technique?
1. Pre- contrast phase (not always the same time as sialogram). Exclude other pathology which could account for symptoms e.g odontogenic pathology - use as a base line.
124
What is the second phase of sialography technique?
2. Contrast/filling phase. Contrast been injected into cannula.
125
What is the third phase of sialography technique?
Emptying phase - roughly 5 minute time delay following removal of the cannula. Contrast should have emptied from the gland and duct into the oral cavity (in a normal functioning gland).
126
What is the contrast used for sialography?
Iodine based. Aqeous as a base as this is easier to excrete and cause tissue reactions. Iso-osmolar. Example is called omnipaque
127
What is the normal findings of sialography?
Parotid gland has a "tree in winter" appearance
Submandibular gland has a "bush in winter" appearance
however if acinic changes then this can have a "snowstorm" appearance.
128
What are some technical considerations to consider when doing a sialography?
- contrast into the oral cavity
- air bubbles in tubing
- Over-filling - "blushing"
129
What would you do if the patient has an allergy to iodine?
MRI sialography - heavy T2W scan - gets rid of all tissues apart from fluid.
130
What is the interventional technique
Not routinely done in Scotland. 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.
131
What are the disadvantages of using the interventional technique
- Can need multiple attempts and stenting to keep the duct patent.
- Sometimes not possible due to extent of scarring from chronic infection
132
What is the selection criteria for stone removal?
1. Stone must be mobile
2. Stone should be located in the lumen of the main duct- distal to posterior border of the mylohyoid
3. Stone should be distal to hilum or anterior border of the gland (parotic)
4. Duct should be patent and wide to allow passage of the stone.
133
Dry mouth is typically in patient with what suspected disease?
Sjorgens disease.
134
What other special investigations and clinical findings are used alongside dry mouth.
- Blood tests (auto-antibodies)
- Schirmer test
- Sialometry
- Labial gland biopsy
135
What differences will you see on an ultrasound with sjorgens syndrome compared to normal.
Loss of margins of gland - less well defined. Leopard appearance. Ductal dilation and mucous plugging.
136
What clinical features are you looking for in an ultrasound for sjorgens.
- atrophy
- heterogenous parenchymal pattern (leopard print)
- hypoechoic
- fatty infiltration
- anything that suggest MALT lymphoma
137
Will Sjorgens syndome affect one parotid gland or both?
Both
138
What does Sjorgens syndrome look similar to in an ultrasound and how can you differentiate this?
Looks similar to chronic sialadenitis on an ultrasound - chronic sialadenitis usually one parotid gland with a clear obstructive history whereas Sjorgens affects both.
139
What are other changes in the salivary gland that can mimic Sjorgens syndrome?
Radiotherapy (Causing atrophy), SLE, sarcoidosis.
140
What are the different stages of Sjorgens syndrome?
Class 1- punctate
Class 2 - globular
Class 3- cavitation
Class 4 - destructive
141
What is Scintigraphy?
IV injection of radioactive Technetium 99m pertechnetate. Half life is 6 hours, use gamma camera to gain images. This assess how well the glands are working. Uptake into the glands if they are working well. Most tumours have reduced uptake, apart from Warthins tumour.
142
Is scintigraphy a high radiation technique?
Yes.
143
What is the first line imaging you would typically use for a patient with swelling to rule out obstruction or neoplasia?
Ultrasound.
144
If neoplasia is suspected on an ultrasound, a biopsy will be required. What are the 2 routine techniques used to carry out a biopsy?
1. Fine needle aspiration for cytopathological diagnosis.
2. Core biopsy for tissue histopathological diagnosis.
145
What one a pleomorphic adeoma (Wartins tumour) typically look like on an ultrasound?
- well defined
- encapsulated
- peripheral vascularity
- no lymphadenopathy
146
What would a malignant tumour typically look like on an ultrasound (e.g mucoepidermoid carcinoma, acinic cell carcinoma and adenoid cystic carcinoma).
- irregular margins
- poorly defined
- increased/tortuous internal vascularity
- lymphadenopathy
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Why would you biopsy every lesion found within a gland.
Low grade malignancy will mimic benign tumours.
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What imaging modality would be required for a pre-surgical assessment for neoplastic lesions?
MRI (more common) or CT
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Why would you aim to have an MRI before the biopsy?
Inflammatory appearances will appear on the scan which may complicate diagnosis. Deep margins of the lesion may be seen which wouldnt of been shown on the ultrasound.
150
In what clinical situation would you consider imaging the minor salivary glands?
If salivary glands are enlarged or pathological
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Typically what imaging would be used to view the minor saliva glands?
Ultrasound (MRI may be beneficial if deeper or possible bony involvement).
152
In general, do minor salivary glands have a higher or lower chance of malignancy if pathological than a lesion in the major salivary glands?
Higher (the smaller the gland the higher the chance of malignancy).
153
What causes imaging on a radiograph to look radiopaque?
- increased thickness of the bone
- osteosclerosis of the bone
- presence of abnormal tissues
- mineralisation of normally non-mineralised tissues
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What is an odontoma?
Benign tumour composed of dental tissues (enamel, dentine and pulp).
Has similarities to normal teeth - surrounded by a dental follicle.
They mature to a certain stage (ie do not grow definitively).
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What is the incidence of an odontoma?
1st or 2nd most common odontogenic tumour (vs ameloblastoma).
Most common in 2nd decade
Correlates with development of normal dentition
F=M
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What are the 2 different subtypes of odontomas and how do they differ radiographically?
1. Complex (ordered dental structures) - may present as multiple "mini teeth" (ie denticles), more common in the anterior maxilla.
2. Compound (disorganised mass of dental tissue)- may have a clump of cotton appearance. More common in the body of the mandible.
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Generally what radiographic features to look for in odontomas?
Well-defined radiopacities of varying radiodensity
Areas with radiodensity of enamel
Thin radiolucent margin (ie follicle)
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What clinical issues arise from an odontoma?
Same issues as an unerupted tooth:
- impaction of adjacent teeth
- external root resorption of adjacent teeth
- development of dentigerous cyst.
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What is the management of odontoma?
- excision
- no risk of recurrence
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What is idiopathic osteosclerosis?
Localised area of increased bone density of unknown cause. No association with inflammatory, neoplastic or dysplastic processes. Normally asymptomatic therefore incidental finding on radiograph. Potential relevance to orthodontics.
A.k.a "dense bone island" or "enostosis"
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What is the incidence of idiopathic osteosclerosis ?
- Up to 6% of the population
- Typically presents in adolescence (stops growing by adulthood)
- Most common in premolar-molar region of mandible
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What is the typical radiographic presentation of idiopathic osteosclerosis.
- well defined radiopacity
- Often homogenous but can have slightly radiolucent internal areas.
- No radiolucent margin
- Variable shape <2cm
- Not associated with teeth but will often appear next to them simply due to circumstance.
- Teeth not displaced
- No affect on PDL spaces of teeth
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What is sclerosing osteitis?
Localised area of increased bone density in response to inflammation. Inflammation often low grade and chronic. May have concurrent symptoms due to source of inflammation. No expansion or displacement of adjacent structures.
A.k.a condensing osteitis
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What is the typical radiographic presentation of sclerosing osteitis?
Well defined or poorly defined radiopacity
Directly associated with source of inflammation e.g apex of necrotic tooth, infected cyst etc.
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How can you differentiate between sclerosing osteitis and idiopathic sclerosis?
If radiographic features inconclusive then look for a source of inflammation e.g check for signs/symptoms; sensibility of teeth.
166
What is hypercementosis?
Excessive deposition of cementum around root.
Non-neoplastic and asymptomatic
Tooth vital (unless necrotic due to another reason)
Cause unknown - but more common in certain conditions e.g Pagets disease of bone, acromegaly
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What is the clinical relevance of hypercementosis?
Makes extractions more difficult
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What is the typical radiographic presentation of hypercementosis?
- Single or multiple teeth involved (involves either entirely of root or just a section.
- Homogenous radiopacity continuous with root surface (radiodensity subtly different to dentine of root)
- PDL space of tooth extends around periphery
- Margins often smooth but can be irregular
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What is a cementoblastoma?
Benign odontogenic tumour of cementum
- occurs around a tooth (which remains vital)
- often painful
- can displace adjacent teeth and bone
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What is the incidence of cementoblastoma?
- Rare
- Wide age range but often in 2nd - 3rd decades
- Typically affects mandibular premolars or 1st molars.
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What is the typical radiographic presentation of cementoblastoma?
- Attached to a tooth root (root outline may become distinct)
- Thin radiolucent margin continuous with PDL space of root
- Well defined and radiopaque (typically homogenous and round)
- Can be mixed radiodensity and irregularly shaped.
172
How can you tell the difference between hypercementosis and cementoblastoma?
Cementoblastoma usually in younger patients and commonly in the mandibular premolar/molar region and will have pain.
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What is a tori?
Bony protuberances of normal bone at characteristic sites.
Asymptomatic
May slowly increase in size
Cause is unknown- potentially related to genetic factors and masticatory stresses.
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Where are common sites for a tori?
- middle of hard palate (torus palatinus)
- Lingual to mandibular premolars (torus mandibularis)
175
What is the clinical relevance of having a tori?
- Can hamper denture wear
- Potentially traumatised during eating
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What is the incidence of tori?
- Varies between populations
- Torus palatinus (20% of the population - often arises before age of 30)
- Torus mandibularis (8% of the population- often arises in middle age)
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What is the clinical and radiographic features of tori?
- solitary or multiple (torus mandibularis often bilateral)
- consist of cortical bone or a mix of cortical and trabecular bone
- Sessile or pedunculated
- Variable size
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What is an osteoma?
- Benign tumour of bone
- Can occur anywhere but has predilection for craniofacial skeleton
179
How does an osteoma typically clinically present as?
Clinically presents as hard, asymtomatic, slow-growing lump. Can be single or multiple.
180
What is the incidence of osteoma?
- Rare
- Wide age range
- Posterior mandible is most common jaw site
181
What is the typical radiographic presentation of osteoma?
- Entirely cortical bone or a mix of cortical and trabecular
- sessile or pedunculated
- rounded, smooth margins
182
What is the clinical relevance of osteomas?
- No malignant potential
- Cosmetic or functional issues --> excision
- Multiple osteomas may indice Gardners Syndrome
183
What is Gardner syndrome?
Rare variant of Familial Adenomatous Polyposis
Characterised by triad of of clinical manifestations:
- Colorectal polyposis
- Osteomas (especially of mandible)
- Soft tissue tumours (eg epidermoid cysts of skin)
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What dental issues do patients tend to have with Gardners syndrome?
- supernumeraries
- impacted teeth
- multiple areas of idiopathic osteoschlerosis
185
Why is it important for patients with Gardners syndrome to be diagnosed early?
- Colorectal polyps inevitably become malignant (mean age of cancer diagnosis: 39 years)
-
186
What type of inheritance pattern is Gardners syndrome?
Autosomal dominant- often a family history of polyposis but can occur spontaneously.
187
What would you do if you identified the presence of multiple osteomas and impacted teeth in undiagnosed patients?
Refer for genetic testing and investigation
188
What is cleidocranial dysplasia?
A rare genetic condition with various skeletal defects (including teeth and jaws)
189
What affects does cleidocranial dysplasia have dentally?
- Generally delayed eruption
- Multiple supernumeraries --> impaction of other teeth
- Multiple unerupted secondary teeth due to multiple retained primary teeth
- Hypoplastic maxilla with high arched palate
- Increased prevalence of cleft palate
- Coarse trabecular pattern
190
What affects other than the teeth and jaws does cleinocranial dysplasia have on the body?
- small maxillary sinuses
- absent or partially formed clavicles
- Bossing "bulging" of the skull
- Hypertelorism
191
Give a definition of osteomyelitis.
Inflammation of the bone and bone marrow due to bacterial infection
192
Give a definition of osteoradionecrosis.
Bone death resulting from irradiation. Requires high energy of radiation (eg radiotherapy)
193
What is MRONJ?
Bone death associated with anti-resorptive or anti-angiogenic drugs.
194
What is the typical radiographic features of osteomyelitis and osteoradionecrosis?
*osteolysis and osteosclerosis of affected region results in a variable mixture of radiolucent and radiopaque areas*
- Irregularities on inner/outer aspect of cortical bone
-Sequestration of bone
- Periosteal bone reaction (primarily in osteomyelitis)
- Loss of lamina dura around teeth
- Pathological fracture of the bone
195
What is central giant cell granuloma?
Reactive lesion with benign tumour like behaviour
- Slow growing lesion causing expansion of bone and displacement of teeth (minority of cases more aggressive and grow rapidly)
- Often asymptomatic but may be tender to palpation
- May invade into the overlying soft tissues
196
What is the incidence of giant cell granuloma?
- Wide age range but majority before age 20
- F>M
- Most commonly affects mandible anteriors to molars.
197
Describe typically central giant cell granuloma from a radiograph using the 8 different characteristics when diagnosing.
Site: mandible anterior to molars
Size: any size
Shape: unilocular or multilocular (when large), internal septae thin if present
Margins: well-defined; poorly corticated; scalloped.
Internal structure: radiolucent
Tooth involvement: No
Effects: Displacement of cortices; displacement of teeth; occasional external root resorption
Number: Single
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What is a fibro-osseous lesion?
A group of rare, benign, non-inheritable conditions where normal bone is replaced by connective tissue and abnormal bone.
199
What are the 3 main types of fibro-osseous lesions?
1. Cemento-osseous dysplasia
2. Fibrous dysplasia
3. Ossifying fibroma
200
Fibrous dysplasia and ossifying fibroma can affect any part of the skeleton but have a predilection for the jaws. True or false?
True.
201
Cemento-osseous dysplasia affects the whole skeleton, true or false?
False- only affects the jaws.
202
How would you diagnose a fibro-osseous lesion and why is it important to have an accurate diagnosis?
Histopathology can be unable to distinguish between the different types therefore radiology plays a major part in diagnosis.
Accurate diagnosis is important as prognosis and treatment options vary greatly. Inappropriate management increases patient morbidity.
203
What are the 3 forms of cemento-osseous dysplasia?
1. Focal (single or few localised lesions)
2. Periapical (lesions associated with apices of anterior mandibular teeth)
3. Florid (extensive lesion or many lesions)
204
What is the incidence of cemento-osseous dysplasia?
- Typically presents age 30-50
- F>>M
- Most common in black ethnicities
- Mandible > Maxilla
205
Clinically what would cemento-osseous dysplasia present as?
- Often clinically no signs or symptoms
- May be expansile (especially florid type)
- Rarely painful
- Can become infected: pain, suppuration etc
206
Typically what would cemento-osseous dysplasia look radiographically?
- Well defined radiolucency containing varying amounts oh well defined radiopaque material. Appearance depends on stage of lesion maturation. Fully mature lesions can appear entirely radiopaque.
- Lamina dura lost
-PDL's often unaffected
-Rare to have tooth displacement or external root resorption
207
How would you manage cemento-osseous dysplasia?
Usually no management required - removal only recommended if exposed by extraction, mandibular atrophy, trauma etc.
208
What is there a risk of following interventions for cemento-osseous dysplasia?
Secondary infection- biopsy best avoided unless atypical presentation e.g rapid expansion. Ideally avoid dental extraction of involved teeth.
209
Why would you consider periodic radiograph reviews in COD.
To check for development of secondary solitary bone cysts.
210
What are the 3 forms of fibrous dysplasia?
1. Monostotic (single bone affect most common)
2. Polyostotic (multiple lesions affecting multiple teeth)
3. Craniofacial (typically single lesion affecting multiple fused bones).
211
What is the incidence of fibrous dysplasia?
- 1:30,000
- Mean age of presentation : 25
-F=M
- Favours posterior maxilla
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What is the typical clinical presentation of fibrous dysplasia?
- Facial swelling (bony expansion may "burn out").
- May displace teeth
- Typically painless
213
What is the typical radiographic presentation of fibrous dysplasia?
- Altered bone pattern. Highly variable: granular, "orange peel", "swirling", "wispy", amorphous. Radiodensity increased as lesion matures.
- Bone enlarges but maintains rough anatomical shape.
- Margins indistinct and blend into adjacent bone. "Broad zone of transition".
214
How would you manage fibrous dysplasia?
- No management required if not causing functional or aesthetic issue (recontouring or radical ressection only if necessary).
*Lesions normally stop growing but may reactivate, typically after a precipitating event eg pregnancy or jaw surgery*.
215
What is ossifying fibroma?
Fibro-osseous neoplasm occuring most often in tooth bearing areas. Majority occur in the mandible. Rare cases in other craniofacial bones.
216
What is the typical clinical presentation of ossifying fibroma?
- Slow growing, bony swelling, although juvenile subtype can grow rapidly. Often painless.
217
What is the incidence of ossifying fibroma?
Occurs at any age
Mean age at presentation: 31 years
F>M
218
What is the typical radiographic presentation of ossifying fibroma?
- Rounded, expansile lesion affected teeth displaced and may be resorbed.
- Ranges from entirely radiolucent to completely radiopaque (radiodensity depends on stage of lesion maturation).
- Margins usually well defined
- Surrounding bone may be sclerotic.
219
How would you manage ossifying fibroma?
Removal indicated due to progressive growth. Surgical enucleation or resection (usually enucleates in one piece). Recurrence rate 12%.
220
What is Pagets disease?
Chronic condition causing disordered remodelling of bone. Affects multiple bones at the same time. Results in enlargement of bones, malocclusion, nerve impingement (e.g cranial nerve deficits). brittle bones. Majority asymptomatic.
221
What is the incidence of Pagets disease?
Up to 5% patient > 55 years.
Rare < 40 years.
M>F
More common in UK than most other parts of the world.
222
What is the typical radiographic presentation of pagets disease?
- General enlargement of bones
- Abnormal bone pattern (eg cotton wool appearance)
- Osteolytic or osteosclerotic patches of bone
- Radiodensity of altered areas linked to stage of disease: Early/osteolytic --> Intermediate/Mixed --> Late/Osteosclerotic
223
What dental issues arise from pagets disease?
- Migration
- Hypercementosis
- Loss of lamina dura
224
What is osteoporosis?
Decreased bone mass - age related or secondary to nutritional deficiencies, medications etc
225
What are radiographic features of osteoporosis?
- Thinned cortices (e.g inferior body of the mandible)
- Sparse trabecular bone pattern (general radiolucent appearance)
- Thinned lamina dura around teeth
