It is a medical imaging technique used in radiology to create images of the anatomy and physiological processes inside the body. MRI scanners use strong magnetic fields, magnetic field gradients, and radio waves to generate images of organs within the body. MRI does not involve the use of X-rays or ionizing radiation, which distinguishes it from computed tomography (CT) and positron emission tomography (PET) scans.

Compared to CT, MRI provides better contrast in images of soft tissues, such as the brain or abdominal region. However, since the examination is performed with the patient lying inside a long and narrow tube, it may be perceived as less comfortable by patients; “open” MRI designs, however, largely alleviate this discomfort.

In some MRI examinations, a contrast agent injection is used. The contrast agent contains gadolinium, a rare earth metal. When present in the body, this substance alters the magnetic properties of nearby water molecules, thereby improving image quality. This increases the sensitivity and specificity of diagnostic imaging.