Clinical Assessment of Breast Volume

Abstract and Introduction

Abstract

Background: 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.

Introduction

Breast volumetry is an important tool in breast reconstructive surgery. Accurate breast volume assessment is needed for pre-operative planning and follow-up results. It influences the degree of breast reduction, the choice of breast implants, or the amount of tissue needed for autologous breast reconstruction, and is used for progression control in autologous fat transplantation.^[1,2]

There is no widely accepted technique for breast volume measurement due to a lack of information regarding the accuracy and comparability of each method. Many have not met the requirements of reproducibility, patient compliance, and cost efficiency. This has limited the use of breast volume measurement methods in routine clinical practice.^[3]

Many measurement techniques have been proposed to determine breast volume. Available techniques include medical imaging modalities (eg, mammography, magnetic resonance imaging (MRI), and computed tomography), casting, anthropometric measurements, and three-dimensional (3D) imaging.^[2,4–7] Despite the fact that the community accepts water displacement of excided breast tissue as the gold standard,^[7] a review of different measurement techniques for breast tissue has led to a different conclusion.^[3] Most available methods to measure breast volume are associated with a large (>200 ml) uncertainty in breast volume.^[5,6,8,9] MRI scanning consistently demonstrated the highest accuracy, reporting errors lower than 10%, and highest reproducibility.^[1] It was regarded as the best method available to determine the breast volume. However, this technique is relatively expensive and time-consuming.

3D imaging is regaining popularity worldwide. Volumetric analysis can be used to document changes in breast morphology and is described in several studies.^[10–13] However, there are a few studies available directly comparing 3D breast volume with MRI measured volume of the breast, which is the best objective standard for breast volume. Kovacs et al. have a limited study population of 12 breasts in 6 patients.^[6] Koch et al. described a correlation between 3D imaging and MRI in only 22 women.^[14] Others lack an objective gold standard or a sufficient study population.

As a result, objective breast volume measurement is not often performed in clinical practice. 3D imaging is however well-tolerated, non-invasive, and performed within a short time and easy to handle. Plastic surgeons now prefer to use their clinical judgment to estimate breast volume instead. This might lead to subjective results of breast volume, which makes operative planning more difficult and could eventually even lead to post-operative asymmetry.

In this study we want to investigate whether the Vectra XT 3D imaging is a reliable tool for objective breast volume determination in clinical practice. First, 3D breast volumes will be compared with MRI measurements because the authors regard this as the current gold standard in literature. Second, 3D measurements will be compared with the surgeon’s estimation of breast volume, which reflects the current standard in clinical practice.