Preoperative vascular mapping for anterolateral thigh flap surgeries: A clinical trial of photoacoustic tomography imaging

Background Photoacoustic tomography (PAT) is a noninvasive vascular imaging modality that uses near‐infrared pulse laser beams and ultrasound (US) to visualize vessels. We previously demonstrated the utility of PAT for visualizing anterolateral thigh (ALT) perforators in a clinical study of 10 thighs in 5 healthy adults. Evaluation of the correlation between PAT and US findings showed that PAT had comparable diagnostic potential but was superior in visualizing subcutaneous microvessels; however, there was no comparison with intraoperative findings. In this study, we used a newly developed technique to transfer a PAT image to a body‐attachable transparent sheet to compare PAT and intraoperative findings. Methods Eight patients were recruited in this prospective study. Patient age ranged from 32 to 79 years (average 60). Seven ALT flaps were applied in head and neck reconstruction. One flap was elevated in chest wall reconstruction. Each PAT scan of an 18 cm × 13.5 cm region took approximately 5 min. Acquired data were processed three‐dimensionally using a novel imaging software program. Perforator vessel data from PAT imaging were traced and corrected for projection onto medical film sheets. The correlation between the perforator stem portions predicted by PAT and the intraoperative findings at the level of the fascia‐penetrating points was evaluated, and distal branching patterns were analyzed. Results PAT imaging showed 16 perforators in 8 thighs. Intraoperative surgical findings revealed that all the perforator penetrating points at the deep fascia level matched the PAT findings within 10 mm. None of the eight ALT flaps demonstrated postoperative complications. The perforator complexes were classified as type I in three cases (19%), type II in eight cases (50%), and type III in five cases (31%). Conclusions PAT imaging matched the intraoperative findings within 10 mm. Preoperative vascular evaluation allows for the creation of a vascular map for facilitating ALT flap surgeries.