They are not. Having a CT (Scanner / CT) or Magnetic Resonance (MRI) have in common that they are medical tests performed by the Technicians in Radio diagnosis (TSID) and that they provide images of the inside of your body. However, they fulfill this vital task in very different ways:
The CT scan uses ionizing radiation (X-rays) to produce the images, while Magnetic Resonance does not use ionizing radiation.
A CT scan is an X-ray tube moving around the stretcher where the patient is lying down, and as this movement is made, multiple images (x-rays) of the body are obtained using X-rays from different angles. An MRI uses radio waves and powerful magnets to obtain the images, and although the stretcher can be moved, generally during the test the patient and the stretcher do not move. Different sequences are applied, and images are obtained once these are finished.
The CT scan is in the form of a "donut," and during the test, the space between the patient and the team is wider than during an MRI. The MRI is a more or less elongated cylinder, but less "comfortable" than a CT scan. It is because of this design and its dimensions that if you are a person that you usually have claustrophobia or you are prone to overwhelm yourself in closed places, it is more likely that it can happen during an MRI than when performing a CT scan.
If this is the case, you should let the Radio-diagnostic Technician know that you will be tested so that he can inform you directly, show you the equipment and accompany you with his voice and vigilance during the development of the test.
The TAC is handy to evaluate bone injuries and internal injuries technique while the MRI is used to assess exceptionally soft tissue of the patient. The radiologist (a doctor specialized in radio diagnosis), evaluates according to the type of injury if it is convenient to perform one or another technique and even both.
METALLIC OBJECTS IN THE ROOM
In RM rooms it is not allowed to enter with metallic objectives (implanted or external) as they can cause problems in the study and safety. However, in the CT SCAN room, and just like when they perform a simple x-ray, it is allowed to enter the room with metallic objectives, but they should not be in the study area.
The time to perform a CT scan at a CT scan centre is much less than the time needed to perform a Magnetic Resonance Imaging. The TAC is a faster test to perform than an MRI, so in an emergency, it is usually the indicated test for a first diagnosis.
The CT SCAN is a silent test if we compare it with an MRI study, in the CT SCAN you will hear the sound of the Rx equipment spinning around you while in the MRI it is a little more uncomfortable sound but more bearable if we reduce it with plugs or helmets compatible.