Despite of using FFDM in screening, it has a limitation in detection of different breast lesions as fibro-glandular tissue overlapping which is part of the nature of the imaging method makes it very difficult to distinguish abnormalities from normal anatomical structures [20]. So DBT is a modified 3D mammographic technique that overcome this limitation [14].
In our study, we compare the performance of 2DDM alone and with the addition of DBT in detection and characterization of different breast lesions in different breast densities at different ages in females. We find out that the performance of addition of DBT is better than 2DDM alone in correlation with the final diagnosis. Out of the included 39 lesions, the sensitivity, specificity, PPV, NPV and AUC are significantly higher with the addition of DBT (100%, 90.5%, 90%, 100% and 0.952, respectively) than that with DM (77.8%, 80.9%, 77.8%, 80.9% and 0.794, respectively). TP and TN are significantly higher with the addition of DBT (18 and 19, respectively) than with DM (14 and 17, respectively). FP and FN are lower with the addition of DBT (2 and 0, respectively) than with DM (4 and 4, respectively). Moreover, adding DBT shows better overall efficacy reaching 94.9% as compared to 79.5% for DM.
The findings of our study lie in concordance with previous studies. Mall et al. [15] evaluated 144 women aged more than 40 years in Australia and found that the sensitivity, specificity, PPV, NPV and AUC were significantly higher with the addition of DBT (93%, 75%, 64%, 96% and 0.927, respectively) than that with DM (90%, 56%, 0.49%, 92% and 0.872, respectively), TP and TN were significantly higher with the addition of DBT (226 and 375, respectively) than with DM (218 and 283, respectively) and FP and FN were lower with the addition of DBT (126 and 16, respectively) than with DM (222 and 24, respectively). Singla et al. [24] evaluated 100 women and found that the sensitivity and specificity were significantly higher with the addition of DBT (100% and 76.4%, respectively) than with DM (83.6% and 38.78%, respectively). Tucker et al. [28] evaluated 7060 women and found that the sensitivity and specificity were significantly higher with the addition of DBT (91% and 68%, respectively) than with DM (86% and 56%, respectively). Alakhras et al. [2] evaluated 50 women and found that the sensitivity, specificity and AUC were significantly higher with the addition of DBT (70.4%, 78.3% and 0.788, respectively) than with DM (63%, 65.2% and 0.681, respectively). Gillbert et al. [10] evaluated 7060 women and found that the sensitivity, specificity and AUC were significantly higher with the addition of DBT (89%, 69% and 0.89, respectively) than with DM (87%, 58% and 0.84, respectively). Michell et al. [16] evaluated 738 women and found that the sensitivity and specificity were significantly higher with the addition of DBT (100% and 76.4%, respectively) than with DM (83.6% and 38.78%, respectively).
In contrast, Ohashi et al. [19] evaluated 628 women and found that there is no significant difference for AUC with the addition of DBT (0.9376) and DM (0.9160), also a statistically significant difference for specificity with the addition of DBT (98.9%) over DM (99.1%) but the sensitivity was significantly higher with the addition of DBT (83%) than with DM (61%). Yi et al. [31] evaluated 265 women in Korea and found that the sensitivity, specificity, PPV and NPV were non-statistically significant with the addition of DBT in 55 women with extremely dense breast (63.6%, 84.8%,79.2% and 90.3%, respectively) than with DM (59.1%, 75.8%, 61.9% and 73.5%, respectively), but in 210 women with other breast density they found that specificity and PPV were significantly higher with the addition of DBT (98.4% and 97.6%, respectively) than DM (90.5% and 76.8%, respectively).
In our study, the mass detection rate is higher with the addition of DBT (69.2%) than with DM (43.6%) and there is accurate detection of mass margins with the addition of DBT in comparison with DM (92.6% vs. 76.5%). This agrees with Mohindra et al. [17], Yang et al. [30], Mun et al. [18], Hakim et al. [12], Andersson et al. [4] and Poplack et al. [21] studies. Mohindra et al. [17] evaluated 164 women and found that there was statistically significant with the addition of DBT in detection of masses comparing to DM (97.6% vs. 87.6%). Also, there was statistically significant with the addition of DBT in detection of speculated margins in comparison with DM (56.5% vs. 34.7%).
Regarding focal asymmetry in our study, one lesion appeared as focal asymmetry on DM but was detected as a mass on DBT. Two lesions appeared as focal asymmetry on DM but were undetectable on DBT (normal cases on follow-up). Our study goes with Skaane et al. [25] study, where 7 cases were categorized as normal as their lesions were obscured and 2 another normal case were categorized as focal asymmetry on DM. However, upon interrogating the DBT slices, the lesions were clearly seen, and focal asymmetry faded away.
In this study, detection and characterization of calcifications were similar with using DM or DBT. This agrees with Li et al. [13] and Chu et al. [7] in which they found that calcifications can be diagnosed using DM and DBT with similar sensitivity.
Regarding the architectural distortion in our study, two lesions appeared as architectural distortion on DM but appeared as masses on DBT. one lesion appeared as focal asymmetry on DM but presented as architectural distortion on DBT. Thus, our study agrees with Dibble et al. [9], in their study mentioned that the sensitivity of detection of architectural distortion with DBT was found to outperform DM, but specificity was found to be similar between DM and DBT.
Regarding BIRADS score in our study, the addition of DBT allowed more confident up or down grading of the BIRADS score of a lesion. For example, three lesions were upgraded from BIRADS 1 to 2, three lesions were upgraded from BIRADS 1 to 3, one lesion was upgraded from BIRADS 1 to 4, two lesions were upgraded from BIRADS 3 to 4, two lesions were upgraded from BIRADS 3 to 5 and one lesion was upgraded from BIRADS 4 to 5. On the other hand, two lesions were downgraded from BIRADS 3 to 2, one lesion was downgraded from BIRADS 4 to 3 and two lesions were downgraded from BIRADS 4 to 1. This goes with Bahrs et al. [5] whom evaluated 87 patients and found that 4.6% lesions were upgraded to BIRADS 4 and 57.1% lesions were downgraded from BIRADS 3 to 1 or 2 by the addition of DBT.
Regarding recall rate in our study, there is a decrease in recall rate with the addition of DBT 5% versus 13% with DM alone. Many studies were done to compare recall rate with DM alone versus with the addition of DBT, Cohen et al. [8] evaluated 103,070 women and found significantly decrease in the recall rate with the addition of DBT 6.1% versus 7.9% with DM. Rose and Shisler [23] evaluated 59,921 women and found significantly decrease in the recall rate with the addition of DBT 10.9% versus 11.7% with DM. Alsheik et al. [3] evaluated 325,729 women and found significantly decrease in the recall rate with the addition of DBT 8.83% versus 10.98% with DM. Skaane et al. [26] evaluated 84,178 women and found significantly decrease in the recall rate with the addition of DBT 3.6% versus 6.7% with DM. Upadhyay et al. [29] evaluated 880 women and found significantly decrease in the recall rate with the addition of DBT 11.4% versus 17.4% with DM. Powell et al. [22] evaluated 12,781 women and found significantly decrease in the recall rate with the addition of DBT 14% versus 16% with DM. In contrast, Pattacini et al. [32] evaluated 19,560 women and found that no significant decrease in the recall rate with the addition of DBT, it was the same 3.5%.
There is a limitation in our study which is a relatively small number of cases.