[Using a smartphone-compatible thermal camera (FLIR One) for preoperative mapping of DIEP perforators]

The success of surgeries involving free flaps largely depends on accurate preoperative mapping of perforator arteries. Various imaging techniques, such as Doppler ultrasound and CT angiography, are typically used, each having its advantages and disadvantages in terms of cost, accuracy, and patient risk. The main objective of our study is to compare the effectiveness of the FLIR One device for detecting these arteries compared with traditional methods. Thermal imaging appears to be a simpler, less expensive, and less invasive alternative for surgical planning.

The study, conducted at the Regional Hospital Center of Nancy, included 25 free flaps (DIEP) on an exclusively female cohort of 22 patients, with follow-up from 2022 to 2023. Before the procedure, an abdominal-pelvic CT angiography was performed, followed by additional evaluation with thermal imaging using FLIR One and acoustic Doppler examination on the eve of the operation. This approach aimed to provide precise mapping of vascular perforators for each patient. Three different operators performed these markings, and the results were then compared with intraoperative observations. The imaging protocol also included a Doppler examination to validate the results of the thermal imaging. Statistical analyses with intraclass correlation coefficients (ICC) were performed to evaluate the correlation between different preoperative localization methods of perforating vessels.

In 22 patients undergoing 25 DIEP flaps for breast reconstructions, three imaging techniques were used to identify vascular perforators: thermal imaging with FLIR, acoustic Doppler, and CT angiography. FLIR identified the most perforators (n=137), followed by acoustic Doppler (n=128) and CT angiography (n=126). Comparing these with intraoperative results, 66% of perforators identified by FLIR were confirmed, 70% for acoustic Doppler, and 95% for CT angiography. The ICCs shows a significant correlation between these imaging techniques and intraoperative results. FLIR demonstrated a strong correlation with intraoperative observations (ICC of 0.74, P<0.001), followed by a moderate correlation with acoustic Doppler (ICC of 0.56, P<0.03) and CT angiography (ICC of 0.52, P<0.006).

The study concludes that thermal imaging with FLIR is a reliable and effective tool for locating vascular perforators. Although the study and FLIR have their own limitations, the tool presents several advantages such as ease of use, speed, and affordability. These characteristics make FLIR particularly attractive as a complement to traditional detection methods, such as acoustic Doppler and CT angiography.