## 3 Results
### Radiologist Classification  
Table 2 shows, for all 49 patients considered in this study (with calcifications found positives at DBT), the results of the BI-RADS classification for each calcification as performed by an expert radiologist reader on DBT images (refer to Materials and Methods). The  
\begin{table}
\begin{tabular}{c c} \hline \hline
**\# Patient** &
\begin{tabular}{c} **Reference Standard Classification** \\ **DBT-Guided VAB and Follow-Up** \\ \end{tabular} \\ \hline
1 & Benign (B2) \\
2 & Malignant (B5a) \\
3 & Malignant (B5b) \\
4 & Benign (B2) \\
5 & B3 (Negative at follow up) \\
6 & Malignant (B5a) \\
7 & Malignant (B5a) \\
8 & Malignant (B5a) \\
9 & Benign (B2) \\
10 & Malignant (B5) \\  
alignant (B5a) \\
31 & B3 (Negative at follow up) \\
32 & Malignant \\
33 & Benign (B3) \\
34 & Benign (B2) \\
35 & Benign (B1) \\
36 & B3* (Negative at follow up) \\
37 & B3* (Negative at follow up) \\
38 & B3* (Negative at follow up) \\
39 & Benign (B2) \\
40 & Malignant (B5a) \\
41 & Malignant (B5a) \\
42 & Malignant (B5b) \\
43 & Benign (B2) \\
44 & B3 (Negative at follow up) \\
45 & B3* (Negative at follow up) \\
46 & Benign (B2) \\
47 & Benign (B1) \\
48 & Malignant (B5a) \\
49 & Benign (B2) \\ \hline \hline \end{tabular}
\end{table}
Table 1: Reference standard classification (from DBT-guided VAB and follow-up) for each patient included in the study.  
histological results of breast calcifications at DBT-guided VAB (with the clinical follow-up in the case of B3) (reference standard classification) are reported for comparison.  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**\# Patient** & \
\begin{tabular}{c} **Reference Standard Classification** \\ **Dbt-Guided Vab And Follow-Up** \\ \end{tabular} &
\begin{tabular}{c} **Radiological BI-RADS** \\ **Classification** \\ \end{tabular} \\ \hline
1 & Benign (B2) & BI-RADS 4 \\
2 & Malignant (B5a) & BI-RADS 4 \\
3 & Malignant (B5b) & BI-RADS 5 \\
4 & Benign (B2) & BI-RADS 4 \\
5 & B3 (Negative at follow up) & BI-RADS 3 \\
6 & Malignant (B5a) & BI-RADS 4 \\
7 & Malignant (B5a) & BI-RADS 4 \\
8 & Malignant (B5a) & BI-RADS 4 \\
9 & Benign (B2) & BI-RADS 3 \\
10 & Malignant (B5) & BI-RADS 4 \\  
alignant (B5a) & BI-RADS 4 \\
31 & B3 (Negative at follow up) & BI-RADS 4 \\
32 & Malignant (B5a) & BI-RADS 5 \\
33 & Benign (B3) & BI-RADS 3 \\
34 & Benign (B2) & BI-RADS 4 \\
35 & Benign (B1) & BI-RADS 3 \\
36 & B3* (Negative at follow up) & BI-RADS 3 \\
37 & B3* (Negative at follow up) & BI-RADS 3 \\
38 & B3* (Negative at follow up) & BI-RADS 4 \\
39 & Benign (B2) & BI-RADS 3 \\
40 & Malignant (B5a) & BI-RADS 4 \\
41 & Malignant (B5a) & BI-RADS 5 \\
42 & Malignant (B5b) & BI-RADS 5 \\
43 & Benign (B2) & BI-RADS 4 \\
44 & B3 (Negative at follow up) & BI-RADS 3 \\
45 & B3* (Negative at follow up) & BI-RADS 3 \\
46 & Benign (B2) & BI-RADS 4 \\
47 & Benign (B1) & BI-RADS 3 \\
48 & Malignant (B5a) & BI-RADS 3 \\
49 & Benign (B2) & BI-RADS 4 \\ \hline \hline \end{tabular}
\end{table}
Table 2: Reference standard classification (from DBT-guided VAB and follow-up, and radiological BI-RADS classification for each patient included in the study.  
Among the calcifications classified as BI-RADS 4 or 5 (26), 12 were benign (FP) at DBT-guided VAB, and 14 were malignant (true positives, TP). Among those classified as BI-RADS 3 (23), 19 were benign (FP) and 4 were malignant (TP). An overall Positive Predictive Value (PPV) of 37% (18/49) was found from the radiologist assessment (31 FP, refer to Table 3). However, PPV was 54% for BI-RADS 4 or 5 and only 17% for BI-RADS 3.