Contrast material-enhanced magnetic resonance (MR) imaging is reported to be the most accurate modality for determining the extent of breast cancer before surgery. Three-dimensionally rendered MR images can be used as an adjunct in planning breast surgery. Semiautomated methods are used to isolate the breast tissue within high-resolution MR images and to render the skin with a shaded-surface method. Cut-away views reveal lesions in the interior of the breast. Cut-plane shaded-surface display provides the surgeon with information on the size, extent, and spatial relationships of a breast lesion in a simple, intuitive format. This technique can help the surgeon plan a breast biopsy, lumpectomy, or mastectomy that will maximize local control of breast cancer while minimizing cosmetic damage to the unaffected portions of the breast. In a review of 15 clinical cases, cut-plane shaded-surface rendering aided surgical planning in 10 cases.