Different types of scans and imaging

THE BRAIN

MRI/MRAUses magnetic field and

radio wavesThe nuclei of atoms line up

in the direction of the magnetic field

Hydrogen atoms in water are monitored

The hydrogen atoms become excited with more energy due to radio waves, once gone the energy is released and detected

Used in diagnosis of tumours, strokes, brain injuries and infections of the brain and spine

fMRIPossible to study human activitiesLooks at functions using oxygen uptakeDeoxygenhaemoglobin absorbs radio

wavesPart of brain activated needs more

oxygen, less radio waves absorbedCan produce 4 images per second

PET scanningPositron Emission TomographyDetects the radiation emitted

from radioactive substances injected into the body

Gamma rays given off are detected by PET

Gamma rays are converted to photons of light, and electrical signals

The signals convert into slices of images

Can show glucose metabolism in the brain, detect cancer, detect memory disorders and seizures, map brain function

CT/ CAT scanningComputerised Axial

Tomography Use thousands of narrow-

beam X-rays to pass through the tissue at different angles

X-rays are detected forming slices of images of the tissues

CT looks at structures rather than functions

Used to detect brain disease

Small structures cannot be distinguished

qEEG/ Brain MappingCan be used in real time as you don’t need

to keep stillSensors are attached to the scalp

measuring activity from thereThe main use is research into brain

functionNo risks (unlike CT scans for example)They are not as spatially accurate as fMRI