Brain imagingEdexcel A-Level Biology A: Mind map

Exam questions on Brain imaging

1. 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
2. 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
3. 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