Immediate postoperative photograph of a deep inferior epigastric artery perforator (DIEP) flap, being monitored with the Cook-Swartz implantable Doppler probe (Reproduced with permission from: Whitaker IS, Rozen WM, Chubb D, et al. Postoperative monitoring of free flaps in autologous breast reconstruction: a multicenter comparison of 398 flaps using clinical monitoring, microdialysis, and the implantable Doppler probe. J Reconstr Microsurg 2010;26:409-16).