gms | German Medical Science

Introduction: 3D breast assessment by multiple stereophotogrammetry is a newly emerging method. To establish the validity of this method the variability of the measurements has to be investigated. We aimed to establish if there was a correlation of the variability of the measurements and the size of the breasts that were examined.

Method: A prototype 3D imaging system with eight digital cameras for 3D breast assessment was applied (Figure 1 [Fig. 1]). We chose a whole range of different breast shapes and sizes as plaster (Figure 2 [Fig. 2]) and live models (Figure 3 [Fig. 3]) for breast capture to display the large variation in the natural breast appearances. For comparison the examination by water displacement was chosen as the gold-standard in volume measurements (Figure 4 [Fig. 4]). A possible correlation was investigated between the size of the plaster and live models and the reproducibility of the measurements determined by 3D imaging and water displacement. For the statistical testing the Pearson correlation coefficient was assessed to investigate the correlation between the size and the reproducibility, measuring the strength of the linear dependence between the two variables X and Y, giving a value between +1 and –1.

Results: There was a strong correlation between the size of the breasts and the variability of the measured volumes within the plaster models (n=9) (table 1), but not within the live models (n= 6) (table 2). When combining the results of both methods (3D imaging and waterdisplacement) the significance of the relationship increased in both the plaster and live models to a significant level in the plaster models, p= 0.007 (graph 1), but not the live models, p= 0.074 (graph 2).

The lines of the best fit through the data revealed an upward slope, which suggested that the larger the breasts, the more variable the results were = the poorer the reproducibility.

Discussion: Our finding that a poor correlation was determined between the reproducibility of breast volume measurements and the size of the breasts raised the question as to whether this was representative of the general population. Further investigation with a larger sample size would be required to investigate a possible correlation further. Interestingly, a trend was observed that the larger the measured breasts were the poorer the reproducibility of the data was. The application of the method of 3D imaging by multiple stereophotogrammetry in women with larger breasts is new and to date not many study groups have published their experiences in this field. A validation of the reproducibility should be conducted ahead of the clinical application.

Conclusion: 3D imaging by multiple stereophotogrammetry is a promising new method, which should be assessed by a validation procedure in view to breasts of different shapes and sizes. The assessment of the variability of the measurements is part of the validation procedure and revealed that the variability of the measurements increased with the larger sizes of breasts for 3D capture. The larger breasts remain a challenge for 3D breast capture by multiple stereophotogrammetry.