Radiology Tutorial (including selection and perception) Flashcards Preview

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Flashcards in Radiology Tutorial (including selection and perception) Deck (93):

What are the three biological effects and risks of ionozing radition (3)

- Somatic Deterministic
- Genetic Stochastic effects
- Somatic Stochastic effects


Define Somatic Deterministic effects of radiation (4)

- Where there is a threshold dose, below which the effect will NOT occur
- E.g. Sun burn, cataract formation
- Severity is proportional to the dose
- Expect those effects with high radiation doses


Define Genetic Stochastic effects of radiation (3)

- Can occur spontaneously or be caused by radiation
- DNA damage in reproductive cells may lead to congenital abnormalities or mental retardation
- Hence why there is a maximum permissible dose for pregnant woman, but this is not relevant to dental radiographs


Define Somatic Stochastic effects of radiation (4)

- Stochastic effects are subject to the laws of chance
- E.g. induction of leukaemia
- ANY dose, large or small, may produce these effects i.e. there is no threshold dose
- Lower doses have lower chance but not no chance


What is the overall risk to the UK population from dental radiographs? (2)

- Low but accounts for 10 fatal malignancies per year
- Hence the need to keep all radiation exposures as low as reasonably achievable


Before taking a radiograph in CCDH what must you do? (4)

- Examine the patient before referring to radiology
- Check that there are not any previous images that could answer your question
- Provide sufficient clinical information to allow justification of your request
- Check hospital or department guidelines for imaging


What needs to be minimised in terms of radiographs for the patient? (4)

- Repeating exposures unnecessarily
- Undertaking those radiographs where the results are unlikely to affect patient management
- Doing the wrong investigation
- Over-investigating


What are the bitewing protocols for Screening for Caries? (3)

- High caries risk: 6 monthly bitewings until no new or active lesions are apparent
- Medium caries risk: annual bitewings until no new or active lesions are apparent
- Low caries risk: approx. 12-18month intervals in primary dentition then 2year intervals in the permanent dentition (longer intervals if there is explicit evidence of continuing low caries risk, be aware of changes which will affect caries risk in adults e.g. decreased manual dexterity, xerostomia and dietary changes)


What radiographs are required in periodontal disease? (3)

- Bitewings will show bone levels if bone loss is not too severe
- Periapical is required if a periodontal/endodontic lesion is suspected
- Panoramic/OPT of good quality may offer a dose advantage over a large no. of intra-oral radiographs and may be considered if available


What radiographs are recommended for endodontics? (4)

- A recent, good quality, periapical before starting
- Radiograph required to determine the working length
- A post-op radiograph is needed to act as a baseline for the assessment of subsequent bony healing
- Further post-op radiographs are taken annually for up to four years


In general what is the rule for differential diagnoses? (3)

- Shouldn’t have more than three
- Put them in order of relevance
- If you don’t know, give a general area for what it could be


If a fracture does not penetrate all the way through the bone, what is it called? Who is this common in? (2)

- Greenstick fracture
- Common in children


What are you looking for when describing a radiographic lesion? (4)

- Radiolucent/radiopaque
- Size
- Margins – corticated?
- Density


In a fracture what does radiolucency often imply? (1)

- Implies pathological fracture


Give a differential diagnosis for:
Patient cannot wear lower denture any longer as does not fit
Radiograph shows large radiolucency with ragged ill defined margins
Cortical plate thinned, jaw expanded

- Differential diagnosis – malignancy
- Answer: Metastatic deposit in jaw from 1⁰ kidney malignancy


Describe the typical appearance of a keratocyst on a radiograph (4)

- Oval
- Well defined
- Coricated margins
- Expansion to varying degrees


Describe the typical appearance of fibrous dysplasia on a radiograph, who does it usually manifest in and how does it look then? (2)

- Very radiolucent and expanded jaws
- Usually manifests in children, looks more radiolucent in children than adults


What does a sarcoma cause? (1)

- Causes bone cells to produce malignant cells


What is a giant cell lesion? (1)

- Benign lesion of the jaw


Where can malignancy start and how does this affect the radiograph? (2)

- Malignancy can start in overlying oral soft tissues and then penetrate into bone
- Bone destruction would taper as you go further from origin


What is a neurofibrosarcoma? (1)

- Nerve related malignancy


What is a lymphoma? (1,1+2,1)

- Malignant neoplasm arising from lymphocytes
- WHO classified lymphomas into three broad groups according to cell type:
- B, T, NK (natural killer)
- Plus less common groups e.g. Hodgkin Lymphoma
- Blood related malignancy


Lymphomas affecting the oral cavity are mainly what type? (1)

- B-Cell Lymphoma


Who are Non-Hodgkin Lymphomas more common in? What are they often associated with? (2)

- More common in immunosuppression/HIV and autoimmune disease
- Often associated with Epstein-Barr Virus


Who do Hodgkin Lymphomas predominately affect? Often with history of? (5)

- Males predominately
- May have family history
- History of EBV
- Rarely history of HIV
- Rarely the prolonged use of growth hormone


Clinically, where to lymphomas usually present? And occasionally? (2)

- Pharynx or palate
- Occasionally tongue, gingivae or lips


What is a differential diagnosis of Lymphoma? (3)

- HL early stage disease: radiotherapy or chemotherapy
- HL later stage disease: combination chemotherapy alone
- NHL: combination of radiotherapy or chemotherapy, monoclonal antibodies, immunotherapy and haematological stem cell transplantation


What is the prognosis for lymphomas? (2)

- HL has a 90% five year survival
- NHL has a >50% five year survival


Where do most Metastatic Oral Neoplasm appear? Especially where? (2)

- Bone
- Especially the mandibular premolar or molar area or condyle


Where do most metastases originate from? (9)

Carcinomas of the:
- Breast
- Lung
- Kidney
- Thyroid
- Stomach
- Liver
- Colon
- Bone
- Prostate


How many metastatic oral neoplasms are the first manifestation of the original tumour? (1)

- One third


What are, often, the symptoms of metastatic oral neoplasms? (1)

- Asymptomatic


What symptoms can other metastatic oral neoplasms present with? (7)

- Pain
- Parasthesia or hypoesthesia
- Swelling
- Tooth mobility
- Non-healing extraction sockets
- Pathological fracture
- Radiolucency or radiopacity


What is the prognosis of metastatic oral neoplasms? (1)

- Grave. The time from diagnosis of the metastasis to death is often months.


What does a corticated margin imply about a lesion? (1)

- Slow growing


What is a residual cyst associated with? (1)

- Extracted tooth


What is a radicular cyst associated with? (1)

- Non vital tooth


Describe a radicular cyst, what is it frequently classified as, origin, and main cause? (4)

- Frequently classified as an inflammatory cyst.
- It has its origin from the cell rests of Malassez which are present in periodontal and periapical ligament, and in periapical granulomas.
- The main cause of the cyst is infection from the crown of a carious tooth producing an inflammatory reaction at the tooth apex and forming a granuloma.
- The liquefaction of the apical granuloma produces a radicular cyst.


What happens to the lamina dura in a radicular cyst? (1)

- The lamina dura and periodontal ligament space are destroyed in the region where the lesion is attached to the root.


What is a dentigenerous cyst associated with? (1)

- Erupting tooth


What is a keratocyst cyst associated with? What could the appearance be? (2)

- Could come from a lateral periodontal cyst
- Could have a tear drop shaped radiolucency between two teeth


Where does a lateral periodontal cyst develop? How common is it and where is it usually found and why? (2)

- The lateral periodontal cyst develops in the periodontal ligament adjacent to the lateral surface of the root of an erupted tooth.
- It is an uncommon cyst, and when found, is often located in the mandibular premolar region which is an area where supernumerary teeth are frequently found.


What are the clinical features of a lateral periodontal cyst? (2)

- The lateral periodontal cyst is an asymptomatic cyst.
- The involved teeth are vital unlike a radicular cyst.


How does a lateral periodontal cyst appear on a radiograph? And what can occur after microscopic examination? (2)

- On a radiograph, the cyst is seen as a well-defined round or ovoid radiolucency with a radiopaque border.
- If, on microscopic examination, features of an odontogenic keratocyst are observed then the final diagnosis is that of an odontogenic keratocyst.


How can a cyst change from a radicular cyst to a residual cyst? (1)

- When a tooth having a radicular cyst at its apex is extracted, the radicular cyst is left behind in bone and is now called a residual cyst.


What else can a residual cyst arise from? (1)

- A residual cyst can also rise from remnants of the epithelial rests after the extraction of a tooth


What is a residual cyst often misdiagnosed as? (1)

- Primordial cyst


What does a primordial cyst arise from? (2)

- A primordial cyst arises from cystic changes in a developing tooth bud before the formation of enamel and dentin matrix.
- Since the primordial cyst arises from a tooth bud, the tooth will be missing from the dental arch unless the cyst arose from the tooth bud of a supernumerary tooth.


What is a nasopalatine duct cyst and what is it derived from? (2)

- The nasopalatine duct cyst, also known as incisive canal cyst, is the most common nonodontogenic developmental cyst.
- It is derived from the embryonic epithelial remnants of the nasopalatine duct which is enclosed within the incisive canal and normally disappear before birth.


What anatomical feature can a small nasopalatine duct cyst be mistaken for? (1)

- Incisive foramen


What are the other names for a traumatic bone cyst? (6)

- Simple bone cyst
- Hemorrhagic cyst
- Intraosseous hematoma
- Idiopathic bone cyst
- Extravasation bone cyst
- Solitary bone cyst


What is the classification of a traumatic bone cyst? (2)

- Not classified as a true cyst because the lesion lacks an epithelial lining.
- Known as a pseudocyst


What is the pathogenesis and cause of a traumatic bone cyst? (6)

- The pathogenesis of this pseudocyst is not known.
- Many pathologists believe the lesion is a sequela of trauma.
- Trauma produces hemorrhage within the medullary spaces of bone.
- In a normal case, the blood clot (hematoma) gets organized to form connective tissue and then new bone. However, if the blood clot for some reason fails to organize, the clot degenerates and forms an empty cavity or a cavity sparsely filled with some serosanguineous fluid and blood clots.
- It is then called a traumatic bone cyst.
- Most patients are unable to recall any past history of a traumatic injury to the jaws.


Case: ULQ crowns of unerupted teeth have no enamel – dysplastic (mal-formed)
No deciduous teeth present
Localised to one quadrant
a) What does being localised to one quadrant imply? What else could it be? (2)
b) Give a differential diagnosis, what is this disease characterised by? What causes this to happen, give an example (4)

a) - Implies not systemic
- Could be a developmental problem
b) - Developmental segmental odontodysplasia
- Characterised by ‘ghost teeth’
- External influence that stops teeth from growing
- E.g. Radiotherapy


Large radiolucent lesion at the angle of the mandible
Eroded away the cortical plate
Smooth, scalloped margin
Has caused root resorption of LR67
Erroded away external oblique ridges
a) Give a differential diagnosis and what that is

- Ameloblastoma
- Benign odontogenic tumour


What does a lesion that causes root resorption, displacement of teeth and expansion of jaw imply? (1)

- That it is a benign lesion


What else would that type of lesion have? (1)

- Well defined margins


What does the opposite kind of lesion cause teeth to look like? (1)

- Look like they’re floating, due to sitting on a mass of soft (tumour) tissue


In what way are benign tumours aggressive? (1)

- Push anatomy out of the way, e.g. jaws and teeth


How do you describe a radiographic lesion? (6)

a) SITE – tell me where it is
• Anatomy of the bone (not where the teeth are)
- Mandibular: symphasis, parasymphasis, mental foramen
- Maxilla: less anatomy

• If you can measure with a ruler do
• If not say where it extends from and to

• Unilocular (childs cloud) or multilocular – scalloped?
• Round, oval or irregular

• Well defined (could draw around them with a pencil)
• Ill defined (melts away)
• White line = corticated

• Radiolucent
• Radiopaque
• Mixed density – must have BLACK areas i.e. high contrast
• If in doubt say mostly radiopaque/lucent

• Teeth near by
• Nerve canals
• Jaws


What are salivary neoplasms? (2)

- Neoplasms that affect major or minor salivary glands
- Can be benign or malignant


What ages and genders are more affected by salivary neoplasms? (3)

- Older adults
- F>M for benign
- F=M for malignant


What can salivary neoplasms be associated with? (1)

- Breast cancer


What other risk factors are there for salivary neoplasms? (2)

- Tabacoo smoke
- Occupations involving wood dust exposure


Give an expected history for a salivary neoplasm (2)

- Symptomless
- Or swelling and/or pain


What does a slow gradual gland enlargement suggest? (1)

- Benign process


What does pain or facial nerve palsy raise suspicions of? (1)

- Carcinoma


What are the usual clinical features of a salivary gland neoplasm? (4)

- Any salivary swelling
- Especially localised
- Firm and persistent
- May be neoplastic


What is a PSA? What kind of tumour is it? (2)

- Pleomorphic salivary adenoma
- Mixed


What are the clinical features of tumours of major salivary glands, mostly? (4)

- Unilateral swelling
- Affect the parotid
- Are benign
- Are PSAs or Warthin tumour


What is the rule of nines? (3)

- 9/10 tumours affect the parotid
- 9/10 are benign
- 9/10 are PSAs


What is the prevalence of intraoral salivary glands tumours, mostly? (1)

- Less common than major glands but more frequently malignant


What are the clinical features of intraoral salivary glands tumours, mostly? (4)

- PSAs
- Unilateral
- Seen most commonly as a firm, well-circumscribed smooth swelling on the posterior palate
- Occasionally buccal mucosa or upper lip; rarely tongue or lower lip


Most tumours in the parotid are: (2)

- PSAs
- Benign


Most tumours in the lips are: (2)

- In the upper lip
- Benign


Most tumours in the submandibular are: (2)

- PSAs
- Benign but one half are malignant


Most tumours in the sublingual are: (1)

- Malignant


Most tumours in the tongue are: (1)

- Malignant, especially adenoid cystic carcinoma


Describe the characteristics of a Pleomorphic Salivary Adenoma

- Mixed tumour
- Most common tumour
- Usually solitary
- Usually slow growing
- Lobulated, rubbery swelling with normal overlying skin or mucosa, but a bluish appearance if intra-oral
- In intimate relationship with facial nerve and poorly encapsulated, if in the parotid


Give examples of two Malignant Salivary Neoplasms and describe: (1+5, 1+6)

Adenoid cystic carcinoma
- Slow growing
- Malignant
- Infiltrates perineurally
- Metastasizes mainly distantly, not in regional lymph nodes
- Swiss cheese histopathological appearance
Mucoepidermoid carcinoma
- Quite common
- Slow growing
- Low grade malignancy
- Presents as painless, slow growing firm or hard mass.
- Unencapsulated, contains squamous, mucus secreting and intermediate cells
- Good prognosis for low-grade, poor prognosis for high-grade tumours


What is the management for Benign Parotid Tumours? (1)

- Superficial or, when necessary, total parotidectomy


What is the management for Malignant Salivary Neoplasms? Why is extreme care required? (3)

- Wide local resection
- Adjunctive radiotherapy
- Extreme care required to avoid facial nerve


Give examples of Unilocular radiolucent lesions on a radiograph: (3, 1+6, 1+3)

Stafne Cavity
- Denitgerous
- Lateral periodontal odontogenic tumour
- Nasopalatine
- Radicular
- Residual
- Solitary bone
Odontogenic Tumours:
- Adenomatoid
- Odonotogenic Fubroma


Give examples of Multilocular radiolucent lesions on a radiograph: (2, 1+5)

Giant Cell Lesions
Odontogenic Tumours:
- Ameloblastoma
- Ameloblastic fibroma
- Myxoma


What sort of appearance does a Multiple Myeloma have? (2)

- “Punched out” ovoid lesions
- Malignant


How does a Central Giant Cell Granuloma often present? (2)

- Initially small, unilocular radiolucency
- Eventually becoming multilocular and then may mimic hyperparathyroidism brown tumour


What special tests do you need to differentiate a Central Giant Cell Granuloma? (1)

- Blood tests to eliminate hyperparathyroidism


Give some examples of Radiopacities: (5,1+2)

- Unerupted teeth
- Foreign bodies
- Congenital and developmental anomalies
- Odonotgenic cysts and tumours
- Fibrous-osseous lesions
- Inflamed and infected lesions
- Odontogenic lesions
- Osteomyelitis


Give examples of congenital and developmental anomalies that can cause radiopacities (2)

- A torus or bone lump
- Gardner Syndrome – osteomas and often impacted and supernumerary teeth and odontomas. Carriers may have jaw radiopacities


Describe the radiographic appearance of Osteomyelitis: (5)

- Inflammatory reaction leading to osteolysis
- Osteolysis causes bone density to fall by 30-50% so shows on radiograph
- Usually takes 2-3weeks
- Primary chronic osteomyelitis: shows extensive and diffuse sclerosis sometimes with expansion
- Secondary chronic osteomyelitis: shows a mixed radiolucent and radiopaque appearance


Why should you be more cautious when investigating the maxilla for pathology, as opposed to the mandible? (1)

- The maxillary sinus allows pathology such as cysts, polyps or tumours to develop un noticed


What is a cyst? (2)

- A cyst is an epithelium-lined sac containing fluid or semisolid material.
- In the formation of a cyst, the epithelial cells first proliferate and later undergo degeneration and liquefaction.


What are odontogenic cysts in terms of cells? (2)

- Odontogenic cysts are those which arise from the epithelium associated with the development of teeth.
- The source of epithelium is from the enamel organ, the reduced enamel epithelium, the cell rests of Malassez or the remnants of the dental lamina.