Bone imaging Flashcards
What are the types of imaging?
X-ray
Bone scans
Magnetic resonance imaging- MRI
Ultrasound
Computed tomography- CT
How does x-ray work?
Uses electromagnetic radiation
Dense areas appear white, less dense areas appear darker
E.g. used in Rheumatoid Arthritis, OA
Advantages of X-ray?
No pain
Low radiation dose
Inexpensive
Supports medical & surgical treatment planning
Disadvantages of x-ray?
Risk of developing cancer- due to radiation- causes cell to mutate
Provides basic anatomical info for only few tissue densitities
Can’t do cross sectional imaging
Not 3D
How does an MRI work?
3D images
Body is largely made up of water molecules; hydrogen atoms contain protons which are sensitive to magnetic fields- so line up in the same direction when exposed to a powerful magnet.
- Short bursts of radio waves are sent, knocking protons out of alignment.
- protons realign once signal is turned off, sending out radio signals which are picked up by a receptor, providing exact information on the protons exact location in the body.
E.g. used for joint synovitis
Advantages of an MRI?
Allows for 3D imaging
No radiation
Painless
Allows you to see soft tissue
Detailed info of anatomy
Disadvantages of an MRI?
Expensive
Noisy
Claustrophobia
Picture quality susceptible to movement
How does CT scan work?
3D image
Beam of x-ray rotate in patients body & provide cross sectional images/ slices
Useful for:
- bone fractures
- when calcific lesions are being assessed
Advantages of CT scan?
Detailed image
Fast process
3D image
Disadvantages of CT scan?
Higher radiation
Expensive
Radiation can cause cancer
How does an Ultrasound work?
Live imagining
Good for soft tissues
No radiation
Useful for:
-Confirmation of small joint synovitis and erosions
-For anatomical location of periarticular lesions
- For characterisation of tendon lesions
How does PET scan work?
Shows how well certain parts of your body are working, rather than showing what they look like.
Useful for:
- investigating confirmed cases ofcancer- how far the cancer has spread & how well it’s responding to treatment.
- Plan operations e.g. brain surgery for epilepsy & can diagnose certain conditions like alzeimers.
Works by detecting radiation given off by substance injected into arm called a radiotracer e.g. (FDG)
- similar to naturally occurring glucose (a type of sugar) so your body treats it in a similar way.
- By analysing the areas where the radiotracer does & does not build up, possible to work out how certain body functions are working.
Advantages of PET scan?
Provides detailed 3D image
non-invasive
Quick & Painless
Accurate diagnosis and more accurate treatment plan
Disadvantages of PET scan?
Expensive
Exposure to radiation
Can image false responses if patient has a chemical imbalance, such as diabetes.
