Radiology Flashcards
Name features on a OPT radiograph
Go on notepad on surface- answer 1-35
what is a multilocular radiolucency and the diff diagnosis
a lesion characterised by two or more pathological chambers separated by a septa of bone
diff diag: ameloblastoma, keratocystic odontogenic tumour (KCOT), giant cell lesion aneurysmal bone cyst cherubism odontogenic myxoma
adjacent, coalescing, overlapping compartments
soap bubble appearance
give two examples of each of the bone pathologies
developmental:
inflammatory:
neoplasm:
metabolic:
developmental: tori, cherubism
inflammatory: osteomyelitis (infection of bone marrow), osteitis (infection of bone)
eoplasm: osteoma, osteosarcoma
metabolic: osteroporosis, rickett’s, paget’s, giant cell lesion
Describe what a KCOT looks like radiographically
multilocular
radiolucent
well defined
Describe what a dentigenous cyst looks like radiographicallly
unilocular
ovoid
related to crown of unerupted tooth
attached to CEJ
What are the different radiographic views used for assessment of bone loss
pros and cons of each
opt: full mouth image,
loss of detail, 2-4 ySv radiation
bitewings: only good for posteriors
pa: minimal distortion, can be used throughout mouth
high exposure when FM, time consuming to take
what is the formula used for assessment of bone loss
why is this used rather than measurements in mm
cej to bone crest (mm)/ cej to root apex (mm) x 100
as radiographs images can be distorted and therefore measurements would be inaccurate
what is fibrous dysplasia?
types?
when scar-like fibrous tissue forms instead of bone- weakening bone and causing deformation and fracture
types: monostotic, polyostotic, Allbright syndrome
radiographic and histological appearance of dysplasia?
rads: orange peel/ ground glass appearance
poorly defined margins
histological: metaplastic, woven bone, w/ fibrous islands, ‘chinese character’ trabeculae
what is osteopetrosis?
3 characteristic features?
bone disease that makes bones abnormally dense and prone to breakage
features:
marrow obliteration
pancytopenia - deficiency of all 3 cellular components of blood
denser bones - failure of resorption
what does hyperparathyroidism do
symptoms
increases parathyroid hormone (pth) levels
.:. increases serum calcium levels
hypercalcaemia
symptoms:
generalised osteoporosis
hypercalcaemia
osteitis fibrosa cystica
brown tumours
what are they
what are they a form of
where do they form
what is brown pigment from?
a form of oesteitis fibrosa cystica
giant cell lesions, not neoplasms, just masses that form in areas of excess osteoclastic activity e.g in pt with hyperparathyroidism
formed of granulation tissue and multinucleate giant cells at focal osteolytic regions
brown pigment is from the breakdown of Hb in the small internal BV to form haemosiderin
22 yr old girl attends for XLA LL6 and presents next day upset with large red lesion emanating from socket site
diff diag?
osteitis fibrosa cystica
giant cell granuloma
fibrous epulis
aneurysmal bone cyst
likely to be GCG-
due to pt age (10-25), rapid exophytic growth from XLA site and is in mandible
what info is needed on histo form?
pt name, DOB, MH, drug allergies, address
clinical description, site, size, prov diag, tests required
GDP name, contact details, address
type of sample included and time sampled.
paget’s disease
what is it
signs / symptoms
appearance radiographically?
characteristic histological feature?
normal cycle of bone renewal and repair is disrupted causing bone to become fragile and misshapen
ss- pain maxillary swelling - .:. denture does not fit nerve compression .:. numbness alkaline phosphatase raised to >150 IU/L
rads:
“cotton wool” skull
hypercementosis
variable osteoporosis/ sclerosis
histo: both osteoclasts and osteoblasts appear on same side of lesion
well defined, circular radiopacity localised to roots of 47. surrounded by zone of radiolucency
What is it?
cementoblastoma
rare, usually benign
calcified mass- hence radiopacity
rounded radiolucency related to roots of 32,31,42. rad 6 month later shows gradual opacity development
What is it?
ameloblastoma
rare, usually benign
appears most in mandible
tumour of epithelial, odontogenic origin (enamel forming organ resemblance)
15 y/o bilateral maxillary and mandibular swelling, eyes fixed superiorly
What is it?
cherubism
bone replaced with painless cyst-like growths
elevated alkaline phosphatase
d/d hyperparathyroidism
24 y/o multilocular radiolucency well defined LL mand raised PTH
What is it?
Osteitis fibrosa cystica
a multilocular radiolucency could easily be misdiagnosed as a malignancy here but for the measurememnt of PTH which when markedly raised points to hyperparathyroidism and .:. osteitis fibrosa cystica
precocious puberty and pigmented lesions
What is it?
fibrous dysplasia -
allbrights syndrome
pigmented lesions - cafe au lait spots, light brown patches of skin w irregular borders
77 y/o pakistani woman, hip replacement . low calcium levels, raised alkaline phosphatase
What is it?
osteomalacia
bone SOFTening due to impaired bone metabolism
whereas in osteoporosis bones are hard and brittle
how to check safelight is right wattage in darkroom
safe light- red light, should be 25 W bulb used to illuminate room but not affect radiographic films being processed or stored
coin test:
lay coin on film, turn safelight on, leave for 1-5 minutes. process as normal. when processed fogging from film will .:. appear obvious next to clear unfogged appearance where coin was laying
3 features of ghost images
3 examples of ghost images
features: higher up, opposite, wider horizontally
eg: earrings, hyoid bone, angle of mandible, hard palate
5 indications for dental panoramic radiograph
pt cannot tolerate intraoral radiographs trauma evaluation 3rd molar assessment inc. relationship to ID canal periodontal bone loss pre-surgical assessment
what is the reason for the following errors in an opt…
a) anterior teeth distorted
b) blurred image
c) image too wide
d) molars larger on one side
e) vertical/ horizontal distortion
f) radiograph too dark
how do you prevent positioning errors?
a) pt not in focal plane/ trough
b) pt moved during exposure
c) canine guides set in front of canines
d) pt assymetrically positioned in machine
e) pt moved during exposure
f) overexposure/ overdeveloped/ fogging
use of guides to orientate patient into correct position - bite block, guide lights, hand rest, chin rest
explain the process of fixation and development
fixation: unsensitised silver halide crystals removed from film to produce white/translucent parts of film
development: sensitised silver halide crystals converted to metallic silver forming black/grey parts of film
Give 3 ways to reduce patient dose?
ALARP as low as reasonably possible rectangular collimation 40-50 60-70kv fast Film focal skin distance 20-30cm limit exposures to only neccessary aluminium filtration lead absorption beam diameter no greater than 60cm at end of collimator
What is the compton scatter vs photoelectric effect?
compton: fogged image as xray hits outer electrons and loses direction and energy. decreased image quality
photoelectric: completely white image shown as xray fully absorbed before reaching film. normal
what metal used for absorption
lead
Name metals used in tube
copper tungsten aluminium
5 safety features advised - who advises this
IRR17
ionising radiation regulations
controlled area warning sign placed sign lights up when equipment on light and audible sound during exposure need continuous pressure for exposure exposure stops immediately
alarp
as low as reasonably possible
why should you report radiographs?
medicolegal requirement best practice records audit IRMER2000
compare bissecting and paralleling technique
bissecting- not in contact. not parallel. beam perpendicular to receptor
parallel - in contact, object and receptor parallel. beam perpendicular to receptor.
Give roles for the following according to IRMER2000 employer referrer practitioner operator
e: legal person, safety, regulations, supervisor
r: justify rads, clinically trained, check pt demographics
p: justification, check no previous rads, benefit vs risks
o: check demographics, alarp, exposure, process, report
