Division of Surgery and Interventional Science, 4919University College London, UK.
Department of Plastic Surgery, Royal Free Hospital, London, UK.
Surg Innov. 2020 Dec;27(6):659-668. doi: 10.1177/1553350620945563. Epub 2020 Aug 12.
Three-dimensional (3D) photography provides a promising means of breast volumetry. Sources of error using a single-captured surface to calculate breast volume include inaccurate designation of breast boundaries and prediction of the invisible chest wall generated by computer software. An alternative approach is to measure differential volume using subtraction of 2 captured surfaces. To explore 3D breast volumetry using the subtraction of superimposed images to calculate differential volume. To assess optimal patient positioning for accurate volumetric assessment. Known volumes of breast enhancers simulated volumetric changes to the breast (n = 12). 3D photographs were taken (3dMDtorso) with the subject positioned upright at 90° and posteriorly inclined at 30°. Patient position, breathing, distance and camera calibration were standardised. Volumetric analysis was performed using 3dMDvultus software. A statistically significant difference was found between actual volume and measured volumes with subjects positioned at 90° ( < .05). No statistical difference was found at 30° ( = .078), but subsequent Bland-Altman analysis showed evidence of proportional bias ( < .05). There was good correlation between measured and actual volumes in both positions (r = .77 and r = .85, respectively). Univariate analyses showed breast enhancer volumes of 195 mL and 295 mL to incur bias. The coefficient of variation was 5.76% for single observer analysis. Positioning the subject at a 30° posterior incline provides more accurate results from better exposure of the inferior breast. The subtraction tool is a novel method of measuring differential volume. Future studies should explore methodology for application into the clinical setting.
三维（3D）摄影为乳房体积测量提供了一种很有前途的方法。使用单个捕获表面计算乳房体积时，误差的来源包括乳房边界的不准确指定和计算机软件预测的不可见胸壁。另一种方法是通过减去两个捕获表面来测量差异体积。 探索使用叠加图像减法来计算差异体积的 3D 乳房体积测量。评估准确容积评估的最佳患者体位。 使用乳房增强器模拟体积变化（n = 12）来测量已知体积。使用 3dMDtorso 拍摄 3D 照片，患者垂直 90°并向后倾斜 30°。患者体位、呼吸、距离和相机校准标准化。使用 3dMDvultus 软件进行容积分析。 发现患者垂直 90°时，实际体积与测量体积之间存在统计学差异（<0.05）。向后倾斜 30°时，未发现统计学差异（=0.078），但随后的 Bland-Altman 分析显示存在比例偏差（<0.05）。两种体位下测量体积与实际体积之间相关性良好（r = 0.77 和 r = 0.85）。单观察者分析的变异系数为 5.76%。 将患者置于 30°后倾位可提供更准确的结果，因为可以更好地暴露下乳房。减法工具是一种测量差异体积的新方法。未来的研究应探索将其应用于临床环境的方法。
