Fat grafting is an option for breast augmentation, however does not achieve equivalent results to breast implants. The procedure involves suctioning fat from regions of excess fatty tissue (most commonly the abdomen) and then carefully preparing the fat for re-injection into the breasts. Once the injected fat has reestablished a new blood supply, the tissue may feel quite natural however the size and shape do not match results achieved from breast implants. There are risks of fat grafting in the breasts, including regions of fat necrosis (which are firm areas where the fat has not established an adequate blood supply) and limitations on size. There was initial concern whether injected fat may interfere with detection of breast cancer or cause microcalcifications, leading to false positives on breast imaging. Others questioned whether injected fat stem cells may induce breast cancer. Studies thus far have demonstrated that fat injections appear safe for both reconstructive and cosmetic cases. It may be useful in smaller volume for contouring, for example, to mask implant visibility or rippling in select cases.