Latissimus dorsi (LAT) flap evaluated using SPY. Necrosis of the tips of transversely oriented LAT flaps can occur in some patients; the use of SPY identifies these regions intraoperatively. Panel A shows a SPY image of a LAT flap (head to the left, legs to the right) following rotation to the chest for breast reconstruction. The image shows two parallel scars from a previous biopsy with evidence of poor blood supply across the scars. This area was resected (arrow). Similarly, Panel C shows poor perfusion in the tip of the LAT flap and its underlying muscle (bracket). It is assumed that these regions of LAT flaps in some patients are outside the primary angiosome of the thoracodorsal artery and are supplied by smaller vessels that are divided in the normal harvest of the flap. In both cases, the tissues look perfectly normal clinically (Panel B, arrow and bracket). Each of these regions should be debrided prior to use in reconstruction. As illustrated by this case, variable anatomy can lead to areas of poor perfusion, despite good flap design and excellent surgical technique, that can only be identified through intraoperative imaging.