## 3 Results
### Breast Lesion Sizing: Correlation with Conventional Imaging and Post-Surgery Histology  
For two of the cancer patients, post-surgery histological analysis of the excised tumor demonstrated total tumor sizes which were much larger than the invasive tumor size. This was the case with Patient 002 and Patient 029, as reported in Table 1. The conventional imaging data (Mammography, Ultrasound) and the MBI imaging test results are depicted in Figure 9 for the case of Patient 002 and in Figure 10 for Patient 029. It is interesting to observe in Table 1 and in Figure 9 that for the Patient 002 case the MBI lesion size estimate varies considerably depending on the pc_fib search range. Maximal linear dimension [34; 35; 36; 37; 38; 39; 40; 41; 42; 43; 44; 45; 46; 47; 48; 49; 50; 51] mm, overestimated against the conventional imaging but better fitting to the total tumor size as confirmed with post-surgery histological analysis of the excised tumor, was retrieved with MBI for this lesion. For a subset of 3 out of the five 5 pc_fib search ranges being systematically evaluated in the Wavelia QIF, the irregularly shaped finding of the MBI system extended over a large volume (maximal linear dimension = 51 mm), including the core of the invasive tumor, as identified at triple assessment. By comparison with the patient's mammograms, it was deemed reasonable to consider that the Wavelia MBI system detected either the total tumor, or the invasive tumor and a concentration of fibro-glandular tissue adjacent to it. For the second subset of pc_fib search ranges, the size of the MBI detection was smaller, and its location seemed to correlate closely with the invasive tumor site. Due to the uncertainty on the orientation and the deformability of the patient's breast during the MBI scan, inaccuracies in the 3D reconstruction and localization of the tumor may arise when compared to conventional imaging data. This difficulty is not considered to be MBI-specific though. The registration of multi-modality imaging data of any kind, in the case of soft and deformable organs, like the breast, is a challenging task due to variations in the natural suspended position of the breast in the upright, supine and prone position. \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \multirow{2}{*}{**Patient ID**} & \multicolumn{2}{c}{**Post-Surgery Histology**} & \multicolumn{2}{c}{**MBI**} & \multicolumn{4}{c}{**Conventional Imaging**} \\ \cline{2-9}  & **Invasive Tumor** & **Total Tumor** & **W1** & **W2** & **Max.** & **Mammography** & **Ultrasound** & **Max.** \\ \hline P002 & 20 & 40 & 51 & 34 & 51 & 25 & 15 & 25 \\ P029 & 22 & 35 & 24.5 & 19.8 & 24.5 & 20 & 37 & 37 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Breast lesion size: maximal linear dimension [mm]. Figure 8: Patient 031, Left Breast: Fibroadenoma morphological detection based on persistence, with Wavelia MBI. Patient 029 was a patient with very dense breasts (VBD = 15.4%). It is clear in Figure 10 that the delineation of the margins of the tumor was not evident on the mammogram. In the radiology report, the presence of a 20 mm spiculated mass in the lower outer quadrant of the Left breast and calcifications extending anteriorly and medially from the mass and measuring up to (42 mm) \(\times\) (47 mm) was reported. Ultrasound scan of the Left breast highlighted a 23 mm irregular hypoechoic mass in the lower outer quadrant (concurring with the invasive tumor), and a smaller node of 7 mm with indeterminate appearance, immediately superior to the mass. The total inclusive diameter of both lesions was reported to be 37 mm in the craniocaudal direction, concurring with the total tumor  
Figure 9: Patient 002, Invasive Ductal Carcinoma (IDC) at the 3 o’clock position of the Right breast (Breast density: BIRADS Category c, VBD = 8.5%): Bilateral Mammogram, Ultrasound and MBI test results of the Right Breast. size. MBI highlighted the presence of two persistent ROIs.