Visual Breast Asymmetry Assessment with Optical-Flow Algorithm.

Abstract

Breast surgery is one of the most important procedures in cosmetic and reconstructive surgery. However, there is no ideal method to assess results. One of the greatest difficulties is the subjective aspect of evaluation. In recent years, several objective computer systems have been proposed and validated as assessment methods, such as BCCT®, OBCS®, GBAI©, etc. In this study, we propose a novel system named VIBA©, that uses an Optical Flow (OF) algorithm which objectively classifies results into symmetrical and asymmetrical categories, with a numerical score. Software was developed in MATLAB (MATLAB and Statistics Toolbox Release 2018b, The MathWorks, Inc., Natick, Massachusetts, USA) called VIBA-Calc© (VIBA stands for VIsual Breast Asymmetry). We compared our OF score with the well-established asymmetry scoring system called Objective Breast Cosmesis Scale (OBCS®). In order to do so, we studied 100 frontal photographs of patients who underwent aesthetic breast surgery between 2017 and 2018, from the senior author's private practice. VIBA-Calc© allows the user to load an image and then draw a rectangle containing both breasts. By simply clicking on a button, the program finds the midline of the rectangle and calculates the final score, as well as the color map of asymmetric regions. Classification into symmetric or asymmetric categories using OBCS and VIBA scores agreed in most cases. Concordance between both classification systems was almost perfect in the group of postoperative cases (k = 0.84; p < 0.001), and substantial in preoperative cases (k = 0.76; p < 0.001). Global Cohen's kappa coefficient was 0.80 (p < 0.001). VIBA© is a useful tool for pre- and post-operative evaluation of breasts, that could be used both in reconstructive and aesthetic surgery.