Structural brain imaging Flashcards
What can result from damage to the temporal lobe
People being unable to recognise everyday objects
Describe CT scans
Uses X-rays to assess brain damage
How do CT scans work
- X-ray beams are sent through the patient and picked up with a detector on the opposite side
- Dense areas of the brain absorb the X-rays more and the detector will pick up less X-ray radiation
- Create an image from how much radiation is detected
What happens if an X-ray is only sent from one direction
The image will be unclear
How do they get a clear image using X-rays
The X-ray is rotated to build up a clear 2D slice of the brain from all sides
What is the downside to CT scans
They expose the patient to harmful radiation
Describe an MRI scan
Uses a magnetic field to image the structures in the brain
What does the strong magnetic field over the brain in an MRI cause
Causes hydrogen atoms in the brain to line up with the direction of the magnetic field
What is done after the Magnetic field has caused hydrogen atoms to line up with the magnetic field
A high frequency radio signal is sent towards the atoms, which flips their direction
What will the hydrogen atoms do once the radio signal has stopped
Slowly return to line up with the magnetic field
What happens to the hydrogen atoms as they go to realign with the direction of the magnetic field
They emit some radiation - the more hydrogen atoms their are the more radiation will be detected
Which areas of the brain contain most hydrogen atoms
Areas with water, so they will produce strongest signal
What images does an MRI create
A series of 2D images that can be put together to create a 3D image
