Computed tomography (CT) and magnetic resonance imaging (MRI) are frequently used by medical professionals to visualize internal body structures. Both technologies are capable of producing detailed three-dimensional images, and both play vital roles in patient care. While CT uses X-rays to create images, MRI uses a powerful magnet and radio waves. Which type of imaging a doctor chooses depends on what information they’re seeking, how soon they need it, and the patient’s personal medical history. Below are a few considerations doctors take into account when deciding which to use.