The role of 99mTc-tetrofosmin molecular breast imaging (MBI) in patients with breast lesions

Objectives To assess the role of 99mTc-tetrofosmin MBI in addition to mammography (Mx) in patients with breast lesions.

Methods 321 consecutive patients (26-81 yrs) with breast lesions scheduled for biopsy underwent 99mTc-tetrofosmin MBI using a high resolution dedicated breast camera. MBI and Mx data were compared and correlated to histology.

Results 277/321 patients had BC and 44/321 had benign disease. MBI was positive in 267/277 (96.4%) BC patients detecting 95.6% of carcinomas. Sensitivity was 90.4% in carcinomas ≤10 mm and 99% in those >10 mm. The smallest detected carcinoma measured 1.8 mm. MBI assessed multifocal/multicentric disease in 88.9% of cases and bilateral disease in 100%. MBI was positive in 20 patients with an invasive carcinoma (≤10 mm in 16 cases) each in dense breast and in 5 patients with a carcinoma in situ, all negative at Mx. Moreover, MBI was more accurate than Mx in 41.7% of patients with multifocal/multicentric disease, changing the surgical management in 25% of cases. MBI modified the local staging in further 44 BC patients with a unifocal invasive tumor each in whom it also identified the associated intraductal component missed at Mx. MBI also identified a contralateral tumor missed at Mx. MBI was negative in 38/44 (86.4%) patients with benign disease, most of whom with suspicious findings at Mx.

Conclusions 99mTc-tetrofosmin MBI proved a highly sensitive diagnostic tool, even in the detection of small size BC, while maintaining a high specificity. A wider employment of MBI in patients with breast lesions is thus suggested to increase Mx sensitivity and specificity as well as to better define tumor disease extension, thus guiding the surgeon to a more appropriate surgical treatment.