This is normal. This noise does not become louder during the test, although the human ear may interpret it as such. Ear plugs are often available for use. A technician is in another room operating a computer. An intercom and mirror are in use during the procedure so that the technician can see and hear the patient.
Some patients find the machine to be somewhat claustrophobic.
A mild sedative will help to better tolerate the procedure in such cases. Small children will require teaching and a sedative prior to having an MRI scan. A CT scan is an X-ray often taken of the head, spine or chest. It is done in the Radiology or X-ray Department. You will be on a narrow table and may have straps across your body to maintain position.