Session 1 MSK radiology Flashcards
What is a radiograph/ X-ray?
- projectional image generated by passage of x-rays through an object onto a x-ray detector.
how do X-rays generate an image?
- x-rays travel in a straight line, are absorbed by dense material with a lot of electrons, so don’t hit the detector plate hence appears white.
- whereas if x-ray pass through it appears black (lungs)
discuss the advantages and disadvantages of radiographs.
- quick
- readily available and inexpensive
X involves ionising radiation increasing risk for apoptosis (dose less than CT)
X poor soft tissue contrast resolution
where are X-rays used in MSK imaging?
- skeletal trauma or acute bone and joint injury like fractures or dislocations.
- initial chronic bone or joint pathologies, like chronic osteomyelitis and arthritis.
how would you define a fracture?
- complete or incomplete break in continuity of the bone.
what are the types of fractures? (6)
- transverse : horizontal crack
- linear : medullary vertical crack.
- oblique : diagonal fracture can be non-displaced or displaced.
- spiral : may appear oblique
- greenstick : common in kids.
- comminuted : fragmented bone usually accidents.
what are some radiographic changes seen during childhood?
- ossification of epiphyses and calcification.
- epiphyseal growth plate separating metaphysis and epiphysis decreasing in size.
Fracture healing is consisting of three phases. what are they?
- Inflammatory phase : no radiographic signs.
- reparative phase : callus on x-rays.
- remodelling phase : radiographic union.
describe the inflammatory process.
- haematoma, tissue death and inflammation.
- hours to days.
describe reparative phase.
- angiogenesis, granulation, pro-callus.
- fibrocartillaginous callus.
- hard callus.
- days to weeks.
What is CT scanning?
computed tomography
- use of radiation to build cross sectional images of body to give detailed info about bone structure and pathology to guide injections, biopsies and aspirations in real time.
what are some disadvantages of CT imaging?
- high radiation dose.
- motion artefact if patient moves.
- poor soft tissue detail compared to MRI.
- 1 in million chance of fatal cancer increased to 1 in 2500.
how do you interpret CT scans?
- density of body tissues measured in hounsfield units (HU).
- air and fat appears black as less than 0HU.
- trabecular cone and cortical appear white as more than 100HU.
what is an MRI scan?
- utilizes magnetic resonance of the hydrogen nuclei to produce cross sectional images of body in any plane to define normal anatomy and detect pathology.
- no ionising radiation.
- used to assess bones, joints and soft tissue, assess MSK infections.
differentiate between T1 weighted and T2 weighted MRI.
- T1 is anatomy defining so fats whiter.
- T2 fluid sensitive so brighter.
