Brain Scanning2 Flashcards
How are CT/MRI scans used to make diagnosis
CT/MRI scans are used to make diagnosis by:
Scanning brain, then compare to normal scan to identify differences e.g tumours, bleeds
Looking for density (denser object, whiter it is)
Use scan to find location and size of abnormality
How does fMRI work
fMRI works by:
Radiowaves
Increased supply of oxygenated blood in active areas that reflect fMRI signals
These are seen as white areas
WHat are adv and dis adv of fMRI
Adv of fMRI are: Safer than CT doesn’t use X-rays Doesn’t need special contrast dye Allows brain activity to be observed in real time Dis adv of fMRI are: Not portable More expensive than CT Noisy, have to sit still
What are PET scans used for and when are they useful
PET scan is used to produce detailed 3D images and they are useful for investigating cancer, and diseases of brain
How does PET scan work
PET scan works by:
Radiotracers are injected and used in brain
When tissue is more active, more 02 is required increasing blood flow and this will show up on PET scan as more radiotracer atoms will be present
What are adv and dis adv of PET scans
Adv of PET scans are: Diagnosis and monitoring of Alzheimer’s Used to plan heart surgery Dis adv of PRT scans are: Can only be done once or twice per year for safety Very expensive
Why do we carry out brain scans
We carry out brain scans to :
diagnose disease by comparing to a healthy brain
Identify location of diseased area
Identify size of area affected
What are adv of brain scans
Adv of brain scans are:
Don’t need expensive/dangerous surgery
Can give idea of brain activity
What is radiotracer
Radiotracer is a compound e.g glucose incorporating radioactive isotopes
How does fMRI detect brain activity
fMRI detects brain activity by:
Detects blood flow in brain
Increased brain activity results in increased blood flow
Oxyhaemoglobin absorbs fewer radiowaves
