Use of magnetic resonance imaging Magnetic resonance imaging (MRI) is one of the four imaging modalities used in radiology. In contrast to computed tomography (CT), it does not use radiation. MRI is still developing and the diagnostic capabilities are growing. There are many indications for MRI and in some fields it has replaced CT. With few exceptions MRI is used mainly for elective examinations, and because of the new techniques like diffusion and perfusion MRI in cancer imaging the use is increasing both with regard to work-up and follow-up. For non-malignant lesions MRI is increasingly used thanks to its great soft-tissue contrast capabilities.