The usefulness of addition of breast-specific gamma imaging to mammography in women with dense breast

Background Mammography (MG) has been adopted as a screening modality for breast cancer. However, the diagnostic yield was reported to decrease in women with dense breasts in MG. Several modalities have been introduced to improve the drawbacks. Breast-specific gamma imaging (BSGI) is a new technique in nuclear medicine imaging that could support breast cancer diagnosis. The aim of this study was to evaluate whether the addition of BSGI according to MG category could improve the accuracy of diagnosis and reduce unnecessary studies or biopsies. Results From February 2013 to December 2018, 548 patients with 628 breast lesions were enrolled in this retrospective study. The performances of BSGI and MG were evaluated for detecting breast cancer. We classified subgroups by adding the results of BSGI for BI-RADS category 0 and 4a lesions on MG. For each subgroup, diagnostic performance was calculated in overall and dense/non-dense. Factors associated with false-negative BSGI were evaluated. The sensitivity of BSGI (88.26%) was comparable to that of MG (87.95%) ( P > 0.05). Specificity (81.44%) and AUC (0.85) of BSGI were significantly superior to those of MG (66.83% and 0.77, respectively). In the subgroup analysis of BSGI plus MG, the sensitivity of BSGI + MG0 and BSGI + MG4a were 95.98% and 94.64%, respectively. And specificities were 69.80% and 77.23%, respectively. Sensitivity and AUC of subgroups increased significantly compared to those of MG alone in overall and dense breasts. A nodule ≤ 10 mm and a low Ki-67 showed significant association with the false negativity of BSGI. Conclusions Applying BSGI to MG, notably for breast lesions with BI-RADS category 0 or 4a, could improve the diagnostic performance, even in dense breasts.