Three-dimensional prediction of free-flap volume in autologous breast reconstruction by CT angiography imaging

Purpose: The diagnostic use of computer tomography angiography (CTA) to identify perforating blood vessels for abdominal free-flap breast reconstruction was extended to estimate the three-dimensional (3D) preoperative flap volume and to compare it with the real intraoperative flap weights in order to (1) evaluate the accuracy of CTA-based 3D flap volume prediction, and (2) to analyze abdominal tissue estimation for required breast volume reconstruction. Methods: Preoperative CTA was performed in 54 patients undergoing unilateral breast reconstruction with a free, deep, inferior epigastric artery perforator flap. 3D flap volumes (cm³) based on CTA data were calculated and compared with the actual intraoperative flap weight (g). In addition, a breast volume to flap volume ratio was calculated to analyze whether the estimated 3D abdominal flap volume would match that of the breast to be removed. Results: 40 CTA data sets (74.1%) fulfilled the technical requirements for a reliable determination of flap volume. 3D CTA flap volume prediction showed no relevant differences to the actual flap weight (p = 0.44) and high correlations (r = 0.998, p < 0 .001), allowing a prediction accuracy within 0.29 ± 3.0% (range: from -8.77 to 5.67%) of the real flap weight. Significantly larger flap volumes were harvested compared with the actually required breast volumes ( p < 0 .001), leading to an average of 21% of the remnant flap tissue potentially being discarded. Conclusions: CTA-based 3D flap volume prediction provides accurate preoperative guidelines concerning the needed amount of abdominal tissue that can be harvested to achieve acceptable symmetry.