Clinical Assessment of Breast Volume: Can 3D Imaging Be the Gold Standard?

Abstract

Three-dimensional (3D) camera systems are increasingly used for computerized volume calculations. In this study we investigate whether the Vectra XT 3D imaging system is a reliable tool for determination of breast volume in clinical practice. It is compared with the current gold standard in literature, magnetic resonance imaging (MRI), and current clinical practice (plastic surgeon's clinical estimation).

Methods: Breast volumes of 29 patients (53 breasts) were evaluated. 3D images were acquired by Vectra XT 3D imaging system. Pre-existing breast MRI images were collected. Both imaging techniques were used for volume analyses, calculated by two independent investigators. Breast volume estimations were done by plastic surgeons during outpatient consultations. All volume measurements were compared using paired samples t-test, intra-class correlation coefficient, Pearson's correlation, and Bland-Altman analysis.

Results: Two 3D breast volume measurements showed an excellent reliability (intra-class correlation coefficient: 0.991), which was comparable to the reliability of MRI measurements (intra-class correlation coefficient: 0.990). Mean (SD) breast volume measured with 3D breast volume was 454 cm³ (157) and with MRI was 687 cm³ (312). These volumes were significantly different, but a linear association could be found: y(MRI) = 1.58 × (3D) - 40. Three-dimensional breast volume was not significantly different from volume estimation made by plastic surgeons (472 cm³ (69), P = 0.323).

Conclusions: The 3D imaging system measures lower volumes for breasts than MRI. However, 3D measurements show a linear association with MRI and have excellent reliability, making them an objective and reproducible measuring method suitable for clinical practice.

Fig. 1.

Three-dimensional image of the breast. A, ROI is defined by the landmarks of the breast. B, Automatic calculation of breast volume with landmarks, using Vectra Breast Sculptor.

Fig. 2.

MRI image of the breast. A, For this ROI, the breast contour was followed using the borders of the convexity of the breast to define the lower and upper borders. B, Several extra ROIs were drawn on the axial images in between the upper and lower boundary.

Fig. 3.

Comparison of reliability 3D and MRI breast measurements. A, The Bland–Altman plot comparing the 3D measurements demonstrates a mean difference of 1.73 (limits of agreement ranging from –56.9 to 60.3) between the 2 observers. B, The Bland–Altman analysis comparing 2 MRI measurements demonstrates a mean difference of 38.4 (limits of agreement ranging from –84.5 to 161.3) between the 2 observers.

Fig. 4.

Comparison of measured volume in 3D, MRI and surgeon’s estimation. A, The Bland–Altman analysis between 3D and MRI demonstrates a mean difference of 229.7 (limits of agreement ranging from –158.0 to 617.4). B, The Bland–Altman analysis between 3D and plastic surgeon’s estimation demonstrates a mean difference of –17.7 (limits of agreement ranging from –270.7 to 235.3).

Fig. 5.

A scatter plot of MRI and 3D measurements. A simple linear regression could be performed to predict MRI from 3D measurements (F = 122.6; P < 0.001; R² = 0.71). Y (predicted MRI) = 1.58 × (3D) – 40.