COMMON TESTS EXPLAINED
MRI— an MRI (Magnetic Resonance Imaging) allows us to visualise internal organs, such as the brain. The MRI machine makes loud banging sounds whenever it is taking pictures. An MRI usually takes between thirty minutes to an hour. The patient is laying down for the procedure, inside a tunnel shaped machine.
SPECT— a SPECT (Single Photon Emission Computed Tomography) allows us to see functional information about a specific organ or body system (e.g. the blood supply to the brain). The patient is injected with a radiopharmaceutical 10 or 20 minutes prior to the scan. The scan will be done by a camera the moves around your head (scanning the brain). There are no loud noises associated with this procedure. The only noise you will hear will be the mechanical rotation of the camera. (see here for information)
PET – Positron Emission Tomography is a nuclear medicine imaging technique which uses a radiologically-marked glucose molecule to look at metabolism (use of glucose as fuel) in different areas of the brain. It differs from SPECT in looking at the brain’s uptake of glucose (the brain has high energy requirements and really only uses glucose as fuel), where the SPECT looks at blood flow. The PET scan is integrated with a CT scanner and also uses the same type of camera as the SPECT scan. The scan itself takes around 15-20 minutes, but the glucose is given by injection an hour or so beforehand so the whole process can take around two hours with some waiting in between. (see here for information)
CT—a CT (Computed Tomography) scan takes cross sectional pictures of specific parts of the body and reconstructs them on a computer so they can be visualised. A CT scanner, which is shaped like a large donut, goes around the part of the body to be scanned. A CT scan usually takes about 30 minutes, and as it moves around you may make clicking or buzzing noises. (see here for information)
EEG—An EEG (Electroencephalogram) allows us to look at electrical activity in the brain. For an EEG, about 16-25 electrodes are placed on the scalp to detect and record electrical activity in the brain. The electrodes do not produce any sensation they only record activity.