We read with great interest the article entitled “Detection of Perforators for Free Flap Planning Using Smartphone Thermal Imaging: A Concordance Study with Computed Tomographic Angiography in 120 Perforators” by Pereira et al.1 in Plastic and Reconstructive Surgery. The authors presented the first concordance study comparing smartphone thermography with computed tomographic angiography. We appreciate their work, and because we share a similar interest in thermographic perforator mapping, we want to ask the authors some questions.
In this article, the authors use a novel method of thermographic perforator mapping, first described by Hardwicke et al.,2 using a smartphone thermal camera. The authors do not provide any information about the thermal sensitivity of the thermal camera used (FLIR ONE; FLIR Systems, Inc., Wilsonville, Ore.) or their method of performing thermography. The thermal sensitivity of the smartphone camera is approximately 150 mK, much lower than that of professional thermal cameras (<40 mK) we use, and we think this might influence perforator identification.
During our own research, we found that the method of inducing local skin cooling and then monitoring the rewarming phase is critical for accurate perforator identification. The technical data in the article regarding the way the authors perform thermography and identify the “hot spots” are limited, and we would kindly ask that they share their methodology with us.
The authors identified perforators through thermography and computed tomographic angiography, and then used the distance between the perforator and the anterior superior iliac spine on a line between the anterior superior iliac spine and the superolateral angle of the patella to localize them. We believe that to accurately identify the position of a perforator, it would have been better to use a triangulation method with two coordinates, on two axes, to achieve maximum accuracy.
The authors present an innovative way of performing thermographic perforator mapping using a smartphone camera. The method is fast, easy to perform, and more accessible than conventional thermographic methods, with smartphone-compatible miniature thermal imaging cameras currently retailing at under $200. Although perforator mapping through thermography is now an accepted method, further studies comparing smartphone thermographic cameras to high-end professional cameras are required.
The authors have no financial interest to disclose in relation to the content of this communication. No funding was received for this communication.
Maximilian V. Muntean, M.D., Ph.D.Department of Plastic Surgery
Patriciu A. Achimas-Cadariu, M.D., Ph.D.Department of Oncologic Surgery“Prof. Dr. I. Chiricuta” Institute of OncologyCluj-Napoca, Romania
1. Pereira N, Valenzuela D, Mangelsdorff G, Kufeke M, Roa R. Detection of perforators for free flap planning using smartphone thermal imaging: A concordance study with computed tomographic angiography in 120 perforators. Plast Reconstr Surg. 2018;141:787792.
2. Hardwicke JT, Osmani O, Skillman JM. Detection of perforators using smartphone thermal imaging. Plast Reconstr Surg. 2016;137:3941.