5. brain scans

What is the purpose of structural imaging in brain scans?

Produces a static image of the brain, focusing on the structure of the nervous system.

What can structural imaging help diagnose?

Diagnosing gross intracranial diseases (e.g., tumours) and injuries.

What is the purpose of functional imaging in brain scans?

Produces images of brain activity.

What can functional imaging help diagnose?

Diagnosing metabolic diseases (e.g., Alzheimer's) and showing which brain areas are active during specific tasks.

What is an example of a structural imaging technique?

Computerised Axial Tomography (CT).

What is an example of a functional imaging technique?

Positron Emission Tomography (PET).

What is another example of a functional imaging technique?

Functional Magnetic Resonance Imaging (fMRI).

How do CT scans work?

A series of X-ray beams pass through the head from multiple angles.

What does a CT scan do with the X-ray beams?

A computer compiles these into cross-sectional images of the brain's structure.

Does CT scanning provide information on brain function?

No, it only provides structural images of the brain.

What are the strengths of CT scans?

• Quick to conduct.

What do CT scans help detect?

• Provide accurate details of brain structure, such as detecting tumours.

Why is detecting tumours with CT scans important?

Helps improve understanding of diseases.

What are the weaknesses of CT scans?

• Only produce structural images, offering no information about brain function.

What are the risks of CT scans?

• Pose potential risks due to X-ray radiation exposure.

How do PET scans work?

A small amount of radiotracer (e.g., FDG) is injected into the bloodstream.

What does the radiotracer in PET scans do?

Active brain areas use more glucose, and the concentrated radiation in these areas is detected by the scanner.

What is the result of a PET scan?

Produces bright images on a computer showing active brain areas.

What are the strengths of PET scans?

• Show specific brain areas involved in a task.

What does PET scanning provide evidence for?

• Evidence for localisation of function in the brain.

What can researchers observe with PET scans?

• Brain activity directly.

What are the weaknesses of PET scans?

• Invasive due to the radioactive injection.

What risks are associated with the FDG injection in PET scans?

• May damage cells or tissues and cause allergic reactions to FDG.

What do PET scans show?

• Only show brain function, not structural damage.

How do fMRI scans work?

Measure blood oxygen levels in the brain using radiofrequency energy and magnetic fields.

What happens when brain areas are active during fMRI?

Active brain areas consume more oxygen, and changes in magnetism are detected to create images.

What kind of images do fMRI scans produce?

High-resolution 3D images.

What are the strengths of fMRI scans?

• Produce extremely clear, high-resolution images.

What can fMRI scans show?

• Show which brain areas are most active during specific tasks.

What are the weaknesses of fMRI scans?

• Patients must remain perfectly still, which can be difficult for children or individuals with anxiety.

Why are fMRI scans unsuitable for some people?

• Unsuitable for people with pacemakers or recent metal implants due to high magnetic fields.