Studying the Brain/Scans Flashcards
How does the EEG work?
It measures the overall electrical activity of the brain using electrodes on the scalp. (Lydia)
What kind of picture does an EEG make?
Wavelike patterns on paper (Lydia).
What is an EEG used for?
Diagnosing epilepsy, sleep disorders, strokes, brain tumours, brain infections, CNS disorders.
Advantages of EEG
Non-invasive, painless, inexpensive, safe, provides a general measure of brain activity and has high temporal resolution.
Disadvantages of EEG
Time-consuming, can’t establish precise activity in a particular localised region, only maps the surface of the cerebral cortex, not an imaging technique.
How does a CT or CAT work?
X-ray that makes low resolution images which are computer produced.
What kind of picture does the CAT make?
Tomographic images which are virtual ‘slices’ of specific areas of a scanned object. It is a still-image.
What is the CAT used for?
Diagnosing tumours, blood clots, degenerative diseases (Parkinsons and dementia)
Advantages of using the CAT
Used to determine whether surgery is necessary without needing exploratory surgery, very detailed structural imaging, abnormal neuroanatomy can be detected (tumours), adjacent slices can be combined to create a 3D representation.
Disadvantages of using the CAT
No information regarding brain function, poor localisation, expensive, involves radiation (1 scan = 12 months of exposure to radiation), can’t be used on pregnant women.
What does MRI stand for?
Magnetic Resonance Imaging
What does CAT stand for?
Computed Axial Tomography
How does an MRI work?
Uses strong magnetic fields, radio frequency pulses and computers to produce 3D images from which 2D slices can be displayed.
What is an MRI like for a patient?
The patient is surrounded by a large electromagnet and is exposed to short powerful blasts of strong magnetic fields.
What kind of picture does an MRI make?
3D images from which 2D ‘slice’ can be displayed.
What does an MRI do?
Diagnoses tumours and neurological abnormalities as well as studies the spinal cord.
Advantages of an MRI
Very detailed knowledge regarding structures, 3D imagery, safe, painless, non-invasive, no x-rays or radioactive material, no special preparations required.
Disadvantages of an MRI
Can’t be used with claustrophobic or uncooperative patients. No ferromagnetic materials allowed (Metallic devices like pacemakers or metal in body, jewellery), very expensive.
What does fMRI stand for?
Functional Magnetic Resonance Imaging
How does an fMRI work?
Uses MRI technology to measure brain activity by detecting changes in blood flow.
Relies on cerebral blood flow and neuronal activation being coupled.
STILES
What kind of picture does an fMRI make?
A clear image with the blood flow lit up.
- When an area of the brain is used, blood flow in that area should increase.
STILES
What is an fMRI used for?
Examining brain anatomy.
Observing which part of the brain is handling critical functions.
Monitors growth and function of brain tumours.
Guides the planning of surgery or radiotherapy.
Assesses effects of strokes.
Advantages of fMRI
Dynamic images, doesn’t use radiation, you can see the brain functions safely, non-invasive, high spatial resolution of neural activity, can detect abnormalities that might be obscured by bone tissue.
Disadvantages of fMRI
Time delay (5-8 seconds behind real-time changes), claustrophobic, loud, ferromagnetic material is prohibited and it’s very expensive.