Magnetic resonance imaging ( MRI ) is becoming more widely used in the evaluation of breast lumps because it is particularly sensitive to small abnormalities in breast tissue. MRI is a special radiology technique designed to image internal structures of the body using magnetism, radio waves, and a computer to produce the images of body structures. Cancers generally have a greater blood supply than non-cancerous growths. The images obtained from an MRI may help determine whether a particular area is cancerous as the MRI exhibits greater contrast in those areas with an increased blood supply. In most cases, MRI is performed if results of mammography and ultrasound evaluations are not conclusive.