# Wavelia Breast Imaging: The Optical Breast Contour Detection Subsystem
## 3 Results and Discussion
### D Breast Surface Reconstruction: Indicative Results from the First Ten Patient Scans
The mammograms have been processed with the Volpara VDM (Volumetric Density Measurement) software package [30] and the breast volume has been computed. The Volpara VDM breast volume and density computation have been extensively validated, against MRI breast volume and density estimation [31; 32; 33; 34] and can be safely considered as a valid reference. In [33] breast volume estimates obtained from 186 FEDM (Full Filed Digital Mammography) exams including mediolateral oblique (MLO) and cranial-caudal (CC) views to objective reference standard measurements obtained from breast MRI have been presented. The Pearson's correlation coefficient between the two computations of the breast volume has been found to be as high as 0.97. The Volpara commercial software was used to compute the breast volume and volumetric breast density, based on FFDM data, in this study. In [34], the agreement of three mammographic techniques (Single-energy X-ray Absorptiometry [SXA], Quantra, and Volpara) with MRI for percent fibro-glandular tissue volume, absolute fibro-glandular tissue volume, and total breast volume computation was assessed. In terms of breast volume computation, the squared Pearson's correlation coefficient was reported to be 0.91 between all the three mammographic techniques and the MRI, while the achieved RMSE (Root Mean Squared Error) was found to be 108 mL, 109 mL and 121 mL for the three mammographic methods correspondingly, when compared to MRI. This study involved data from 99 women. Both referenced studies have been used to validate volumetric breast density and also breast volume computation using FFDM data, the validation being performed against computation using 3D MRI data. A similar approach has been adopted in our study to validate breast volume computation using the Wavelia OBCD 3D data, against the computation performed by the already validated Volpara software on the available FFDM data. Results on the 10 first patients that have participated in the first-in-human clinical investigation of the Wavelia system are presented. In Figure 35, the volume of both breasts of each of the ten patients is plotted, as computed from either:  
* the Wavelia OBCD 3D scan data, or
* Cranio-Caudal and Medio-Lateral Oblique). Good level of correspondence between the breast volume computation, as performed by the two distinct imaging modalities, is demonstrated, thus validating the Wavelia OBCD breast surface reconstruction and volume computation. It is interesting to observe that the RMSE error computed  
Figure 35: Comparative presentation of the breast volume, as computed by the Wavelia OBCD scanner (pendulous breast) and the X-ray mammogram (compressed breast - averaging over Cranio-Caudal and Medio-Lateral view captures). between the Waelia OBCD and FFDM (Volpara) breast volume computations based on this first small dataset of patients is 154.6 mL, thus in the same order of magnitude as the RMSE reported in [34] between FFDM and MRI. Significant discrepancy between the X-ray mammography and the Waelia OBCD breast volume computation can be noticed only in the case of Patient 013 (P013). This has most probably been due to the patient not being well positioned on the Waelia scanner, resulting in part of her breasts not being scanned. Patient 003 had very small breasts, potentially difficult to be fully inserted in-between the X-ray mammography plates, resulting in under-estimation of the breast volume by the X-ray mammography in this case. The 'for processing' DICOM files, which are required for processing the mammograms with Volpara VDM, were not available in the case of Patient 010. Finally, in order to evaluate the impact of potential movement of the patient's breast during the OBCD scan, a quality check has been developed and executed after each OBCD patient scan.