MRI, or magnetic resonance imaging, is a non-invasive procedure that uses powerful magnets and radio waves to construct pictures of the body. Unlike radiography and computed tomographic (CT) imaging, MRI does not use radiation to look inside the body.
For a breast MRI, the patient lies face down, with the breast hanging freely into a cushioned recess that contains the coil. The bed then moves into the magnet, a giant, tube-like machine, where the patient must remain still while the scans are produced. MRI is a more sensitive procedure — that is, MRI can reveal additional lesions early on and help identify lesions that warrant biopsy in high-risk women. The procedure is used as an additional test in patients most likely not to have a lesion detected by mammography alone. They include women who have a family history of breast cancer, a genetic predisposition to breast cancer or a firm area in the breast from a scar or recurrent tumor, those who have had breast surgery, and those who show residual tumors near the surgical site that require additional tissue removal.