Brain imagingEdexcel A-Level Biology A: Flashcards

What these 13 flashcards ask

What type of radiation does a CT scan use?
How does a CT scan produce an image?
State two advantages of CT scans.
What does an MRI scan use to produce an image?
State two advantages of MRI over CT.
State two limitations of MRI.
What does fMRI detect?
Why do active brain areas show up on fMRI?
What is a PET scan tracer?
Why does more tracer collect in active areas in a PET scan?
What does the PET scanner detect?
Which scans show structure and which show function?
Give one disadvantage of PET compared with fMRI.

Exam questions on Brain imaging

A 68-year-old woman arrives at an accident and emergency department after a sudden, severe headache and weakness down one side of her body. Doctors need to find out quickly whether she has bleeding inside her skull.
Explain how a CT scan can show the difference between brain tissue, skull bone and a collection of blood.2 marks
A research team wants to find out which areas of a volunteer's brain are most active while she solves arithmetic problems. The team compares two functional imaging techniques, fMRI and PET.
Explain why an active area of the brain shows up on an fMRI scan.2 marks
A patient with suspected Alzheimer's disease is injected with a glucose analogue labelled with a radioactive isotope that emits positrons. A PET scan shows much less uptake of the tracer in some regions of the cerebral cortex than in a healthy brain.
Explain how a PET scan produces an image of activity in the brain.3 marks

Written by the Exaim team, led by Shaun Daswani (Head of Upper Secondary, Improve ME Institute; MSc Financial Mathematics, Imperial College London; BSc, UCL) and Jason Daswani (operational lead, Improve ME Institute; LSE).