CT scan – computerised tomography. Instead of sending out a single x-ray through the body, several beams are sent simultaneously from different angles. The computer then processes the results showing them as a 2D picture. CT scans are less expensive and take less time than an MRI scan, but they have lower resolution so could potentially not show some skull base and low grade tumours, as well as an MRI scan. So, if you have one type of scan rather than another, it is usually because one will be more suited to you.
A CT scan usually lasts around 20 minutes and is quieter than an MRI scan. You lie on a table and the scanner moves around your head. If you need a contrast scan, then an iodine-based contrast agent will be injected. This shows the ‘leaky’ blood vessels in a tumour and enables the neuro-radiologist to see the mass directly.
Other tips if you are having a CT scan – Warm clothing is recommended; it can be chilly in the room. And if you are allergic to shellfish let the radiographer know, because some contrast agents contain iodine.
Reporting is usually done within two weeks. Again – this may be sooner if you have a private CT scan.