Topic 1 - Video 1 Flashcards
Name two types of structural scans
CT Scans (Computerised Tomography) and MRI Scans (Magnetic Resonance Imaging)
In a CT scan, what type of waves are passed through the brain?
Radioactive beams
How does a CT scan work?
The x-ray tube collects images (usually 8 or 9) from all angles of the brain and creates a 3D image. This is then mapped and you can see areas of tissue with variying densitied
What is a CT scan usually used for?
General injuries, strokes or tumors. Mapping general brain abnormalities
What is one drawback from using CT imaging?
Relatively poor spatial resolution, for example you can not distinguish between white and grey matter
What does MRI stand for?
Magnetic Resonance Imaging
What does an MRI measure?
It measures the varying water content in different areas of the brain
How does an MRI actually work? (hard)
A strong magnetic field is passed through the patients head and maps the hydrogen atoms. The hydrogen atoms the align with the magnetic force.
Radio waves are then passed through the brain, the atoms inside then “wobble” and then realign, releasing energy.
The amount of energy released varies from each part of the brain varies depending on the hydrogen concentration in the tissue
What type of imaging is produced in an MRI scan?
Both 2D and 3D imaging
Name 2 non structural scans
fMRI and PET scans
What does fMRI stand for?
Functional Magnetic Resonance Imaging
What does an fMRI measure?
fMRI measures the amount of oxygen in the blood at different parts of the brain during different events. This is then colour coded.
What is a PET scan?
A PET scan means Positron Emission Tomography
How does a PET scan work?
When a PET scan is needed, 2-DG (similar to glucose) is injected into an artery. Cells in a more active area of the brain pick up more tracer and emit more radioactivity. This shows up on a map
What is the main energy source for the brain?
Glucose
