Radiology Flashcards
What is the radiographic appearance of progressive peri radicular disease? (2)
- increased bone resorption and increasing size of radiolucency
- surrounding bone sclerosed
What things can be mistaken for pathology? (6)
- maxillary sinus
- nasal cavity
- mental foramen
- submandibular fossa
- incomplete root development
- intervertebral space
What is the appearance of osteomyelitis? (4)
- ragged moth eaten radiolucency
- radiopaque sequestra of dead bone
- sclerosis of surrounding bone
- periosteal reaction
What is the result of osteoradionecrosis? (3)
- reduction in blood supply to bone
- trauma or infection
- ragged bone destruction
What are the radiological features of sinusitis? (3)
- thickening of the antral mucosa
- increase in secretions, mucous or pus
- on CBCT and CT scans air bubbles may be seen within the radiopacity indicating fluid/mucous
What are the dental causes of sinusitis? (3)
- periapical pathology
- oro antral communication
- possibility of association with implant placement
What is a le fort III fracture?
Through the orbits and separating the base of skull
What does a lateral oblique mandible show?
Most of the mandible including the condyle
What are the disadvantages of a lateral oblique mandible? (4)
- difficult to interpret
- require good cooperation if conscious
- may not show all regions of concern
- fractures can be missed
What does a PA mandible radiograph show?
A good view of the posterior body, angle and ramus of mandible
What is the superimposition of the PA mandible? (2)
- superimposition of cervical spine may obscure anterior mandible
- superimposition of mastoid process and zygomatic eminence obscure condyle
What does a reverse townes show? (2)
- shows condylar head and neck which are often obscured on a PA mandible
- demonstrates medial position
What does a mandibular true occlusal show?
Displacement antero posterior and medio lateral
What does an anterior oblique occlusal show? (2)
- can show roots if periapical not possible
- presence of alveolar fracture if unclear on DPT
Give an advantage of CT scanning
An advantage of CT scanning is that it allows detailed examination in 3 dimensions without superimposition of soft tissue, hard tissue and air spaces
What are the TMJ radiographic views? (4)
- trans cranial
- trans pharyngeal
- trans orbital
- tomographic views using DPT
What are the advantages of MRI? (3)
- useful if need to see soft tissues
- can demonstrate the position of the disc
- no ionising radiation
What are the advantages of cone beam CT? (3)
- more readily available than MRI
- can show disc space and displaced condylar head of patient in occlusion
- can show fairly early bony changes of both condylar head and glenoid fossa
What are the radiological features of sialothiasis?
May be superimposed on the maxilla and mandible on DPT
How does sialography work? (2)
- radiopaque contrast injected into the salivary duct system
- radiographs taken 2 views at right angles to each other
How do you inject into the duct system in sialography? (3)
- use lacrimal dilators to widen duct orifice
- insert canula
- inject approx 1-2ml contrast slowly
What are the indications for sialography? (3)
- acute intermittent swelling of one salivary gland
- generalised swelling of one or more glands
- history of xerostomia
What radiographs are used for the submandibular gland? (4)
- pre contrast DPT
- true occlusal mandible
- filling lateral and AP view
- emptying 1/2 DPT side of interest
What are the features of a normal parotid? (3)
- main duct even diameter
- uniform filling
- branches taper towards the periphery
What is chronic sialadenitis?
Enlargement of ducts particularly main, first and second branches
What is the appearance of chronic sialadenitis? (4)
- dilations can alternate with constrictions like a string of sausages
- rosary or beading appearance
- sialoths may be present or mucous plugs
- truncated ducts give pruned tree appearance
What is the appearance of chronic sclerosing sialadenitis?
Slight enlargement of main and/or secondary ducts, irregularities of duct walls and loss of terminal duct
What are the advantages of an oil based solution? (2)
- densely radiopaque therefore good contrast
- high viscosity therefore slowly excreted from the gland
What are the advantages of an aqueous solution? (3)
- low viscosity therefore easily injected
- easy and rapid removal from gland
- easily absorbed and excreted if extravasated
What is the radiographic appearance of calculi? (4)
- filling defect
- dilation of duct beyond calculus
- emptying of CM slowed
- appears radiolucent compared to the contrast
What is the radiographic appearance of stage II sjogrens syndrome?
Globular pattern
What is the radiographic appearance of stage III sjogrens syndrome?
Cavity pattern
What is the appearance of a malignant lesion neoplasm?
Tumour mass replaces duct pattern
What is the appearance of pleomorphic adenoma? (4)
- ball in hand appearance
- ducts appear to surround tumour
- filling defect in gland parenchyma
- pressure of tumour can extend duct
What is the appearance of a pleomorphic adenoma on a CT and MRI scan? (2)
- round with distinct boundaries
- smooth margin- inside has a higher density
What is the appearance of a pleomorphic adenoma on a ultrasound?
Internal echoes are absent or weak
What is the appearance of a stafne defect? (3)
- aberrantly positioned salivary gland tissue
- deep depression or inclusion at angle of mandible during development
- ovoid radiolucency below ID canal, anterior to angle of mandible
What are the effects of cysts on adjacent structures? (4)
Teeth- displacement and resorption
Cortices of jaw- expansion and perforation
Inferior dental canal- displacement and compression
Maxillary sinus/nose
Why are cysts radiolucent?
- they cause bone to be destroyed
- bone is now less dense
- fewer X-ray photons are absorbed
- more photons hit the film or sensor/plate
- image is blacker in this region
Why do cysts in the antrum look radiopaque?
The surrounding air absorbs fewer photons than cyst fluid
What is the appearance of an incisive canal/nasopalatine cyst? (6)
- heart shaped
- smooth well defined
- corticated
- usually over 6mm
- palatal expansion
- adjacent teeth may be displaced
What are the other names for a traumatic bone cyst? (7)
- smooth outline not markedly corticated
- scalloping of margins
- cortication more obvious inferiorly
- periodontal space traceable
- lamina dura sometimes missing
- growth along jaw
- generally above mandibular canal
What do malignant neoplasms tend to be? (4)
- fast growing
- poorly defined
- invasive and destructive of surrounding tissues
- destruction of bony cortices
What are the presenting features of an oro facial malignancy? (5)
- pain in the jaw
- loose teeth
- non healing sockets
- pathological fracture
- trismus
What are the features to look out for in oro facial malignancies? (4)
- destruction of bone
- ragged margins
- no cortical margins
- spread along inferior dental canal
What is multiple myeloma?
Multifocal plasma cell proliferation
What is the radiographic appearance of a multiple myeloma?
Well defined punched out radiolucencies
What is the result of multiple myeloma? (6)
- bone pain
- fractures
- increased serum calcium
- anaemia
- risk of infection
- kidney damage
What is an osteosarcoma?
Rare primary malignant tumour of bone. Bone lysis but also neoplastic bone is formed
What is the radiographic appearance of osteosarcoma? (4)
- ill defined radiolucency
- widened PDL space
- spiking resorption of roots
- the periosteum is stretched producing new bone which has a characteristic sun ray appearance
What are the most common metastatic or secondary tumours? (5)
- breast
- lung
- prostate
- GI
- kidney
How does scintiscan and SPECT work? (2)
- pt injected with a solution containing technetium 99m
- scanned with gamma camera
How does PET CT work?
- fluoro deoxyglucose injected IV
- increased uptake in metabolically active areas such as lytic bone lesions, metastasis etc
- FDG undergoes radioactive decay with ultimate release of gamma rays
- pt surrounded by a ring of gamma detectors
- low resolution CT taken at same time and PET and CT information is merged into 1 image
What opacities are closely associated with teeth? (4)
- exostosis or tori
- dense bone island
- cement dysplasia
- complex or compound odontomes
What opacities are not necessarily contacting teeth? (4)
- dense bone islands
- fibrous dysplasia
- cement dysplasia
- chronic osteomyelitis
What is the location of fibrous dysplasia?
Posterior maxilla more common than mandible. May affect adjacent bones
What is the radiographic appearance of fibrous dysplasia? (3)
- poorly defined margins
- initially radiolucent gradually becoming opaque
- ground glass or orange peel appearance
What is the dental result of fibrous dysplasia? (4)
- teeth sometimes displaced
- rarely resorbed
- expansion of bone in all directions
- occlusion affected
What is pagets disease also called?
Osteitis deformans
What happens when the skull is involved with pagets disease of bone?
You may develop blindness and deafness
What is the radiographic appearance of pagets disease? (5)
- scalloped circumscribed areas of osteoporosis
- in jaws may develop a ground glass appearance, cotton wool in later stages
- enlargement of bones, separation of teeth
- loss of lamina dura, marked hyper cementosis in late stages
- lytic lesions
What are the dental abnormalities of hypophosphatemia? (3)
- poor teeth formation
- slow or delayed eruption
- spontaneous abscesses
What are the dental abnormalities of cleidocranial dysplasia? (4)
- multiple supernumerary teeth anterior to first permanent molars
- conical supernumeraries anteriorly
- retained deciduous dentition
- unerupted permanent teeth or delayed eruption
What is idiopathic osteosclerosis?
Localised area of increased radio density of bone of unknown cause and without association to inflammatory, dysplastic or neoplastic processes
What are the features of idiopathic osteosclerosis? (2)
- dense bone island
- exostosis
What is the radiographic presentation of idiopathic osteosclerosis? (4)
- well defined non expansile radiopacity
- variable shape
- usually <2cm
- normal PDLS of adjacent teeth
What is the differential diagnosis of idiopathic osteosclerosis if there is no radiolucent margin? (3)
- sclerosing osteitis
- exostosis/torus
- osteoma
What is the differential diagnosis of idiopathic osteosclerosis if the radiolucent margin is continuous with the PDLS? (2)
- hypercementosis
- cementoblastoma
What are the radiographic features of fibrous dysplasia? (3)
- altered bone pattern
- bone enlargens but maintains rough anatomical shape
- margins indistinct and blend into adjacent bone
What are the radiographic features of cemento osseous dysplasia? (5)
- well defined radiolucency with sclerotic rim containing varying amounts of well defined radiopaque material
- lamina dura lost
- PDLS lost or widened
- external root resorption rare
- secondary simple bone cysts may form within lesions
Where does an ossifying fibroma occur?
Almost exclusively to tooth bearing areas
What are the radiographic features of an ossifying fibroma? (4)
- rounded expansile lesion
- margins usually well defined
- radio density depends on stage of lesion maturation
- surrounding bone may be sclerotic
What is the management of an ossifying fibroma? (2)
- removal indicated due to progressive growth
- surgical enucleation or resection
What is a central giant cell granuloma?
A reactive lesion of jaws with benign tumour like behaviour
At what age do the majority of central giant cell granulomas occur?
Before the age of 20
What is the location of a central giant cell granuloma? (2)
- most common anterior to first molars
- mandible>maxilla
What are the radiographic features of a central giant cell granuloma? (2)
- often well defined but poorly corticated
- starts unilocular but become multilocular when large
What is the management of a central giant cell granuloma? (2)
- enucleation and curettage
- radiographic follow up to check for recurrence
What is the differential diagnosis of a central giant cell granuloma? (4)
- simple bone cyst
- ameloblastoma
- aneurysmal bone cyst
- ossifying fibroma
What does basal cell naevus syndrome result in? (4)
- multiple odontogenic keratocysts of the jaws
- multiple basal cell carcinomas of the skin
- abnormalities of skeleton
- marked calcification of falx cerebra
What is gardeners syndrome a variant of?
Familial adenomatous polyposis
What are the features of gardner syndrome? (4)
- colorectal polyposis
- osteomas
- soft tissue tumours
- supernumeraries, impacted teeth and multiple areas of idiopathic osteosclerosis
