Intraindividual comparison of imaging modalities in anterolateral thigh perforator mapping

Accurate knowledge of perforator vessels is crucial for successful perforator flap surgery. The purpose of this prospective, single-center study was to compare three imaging modalities, color-coded duplex sonography (CCDS), flat-panel computed tomography (FPCT) and non-contrast time-of-flight magnetic resonance angiography (TOF-MRA), for preoperative perforator mapping in anterolateral thigh (ALT) free flap reconstruction. Assessment of detection rates, accuracy of the fascial emergence point localization and the accuracy in predicting the subfascial course of perforators was performed using intraoperative findings as the reference standard. This study included ten patients, with 17 perforators identified preoperatively and 15 included in the ALT flap design. CCDS demonstrated the highest observed sensitivity for perforator detection (94%), followed by TOF-MRA (91%) and FPCT (87%) (p = 0.82). FPCT showed a slightly higher proportion (25%) of markings beyond a 2 cm radius from the fascial emergence point compared to CCDS (6%) and TOF-MRA (0%) (p = 0.31). One FPCT inaccuracy was linked to mobilization of the thigh during the examination. Regarding prediction of the perforator course, FPCT showed lower observed accuracy (50%) compared with CCDS (93%) and TOF-MRA (82%) with an overall statistically significant difference between modalities (p = 0.033). This study suggests that CCDS provides high accuracy for perforator detection and prediction of the perforator course, however requiring a certain amount of examiner experience. TOF-MRA, a non-contrast angiographic imaging method, shows to be a reliable, less-examiner dependent alternative making it especially suitable for centers with lower surgical volumes. FPCT is particularly valuable in patients who already require contrast-enhanced vascular imaging of the affected extremity. However, accurate assessment of perforators using FPCT requires consistent immobilization of the patient's lower extremity.