 2. There are higher rates of fat necrosis and flap atrophy that occur after specific types of free tissue transfer flaps, i.e., higher rates occur with Deep Inferior Epigastric Perforator DIEP flaps vs. Transverse Rectus Abdominis TRAM flaps.5, 6 Some authors have suggested that early flap congestion and the development of late fat necrosis may be due to venous insufficiency, without complete venous occlusion 7. We hypothesize that early post-operative changes in the flaps optical properties may be used to predict the development of late complications such as fat necrosis and flap atrophy, as these complications are thought to be due to a relative arterial andor venous insufficiency to the tissue transfer flap; and thus should be reflected in the tissues optical properties as detected by the MI device. 