Molecular breast imaging to screen for breast cancer in myocardial perfusion patients

Objectives Molecular breast imaging (MBI) images the functional uptake of a radiopharmaceutical, 99mTc-sestamibi, with a dedicated dual-head semiconductor-based gamma camera. 99mTc-sestamibi is also commonly used in cardiac stress testing. We offered MBI as an additional test to women presenting for a stress myocardial perfusion imaging (MPI) study. Our objective was to evaluate MBI’s ability to detect breast cancer in this population.

Methods MBI was performed during the waiting period after stress injection, hence, no additional exam time or radiation dose was required. Bilateral MBI acquisitions in the CC and MLO views were performed for 3 min/view. A radiologist interpreted the MBI studies and any suspicious findings were reviewed with past mammogram.

Results 198 women presenting for MPI underwent MBI. Average age was 64 years (range 37-88 years). MBI was negative in 184 patients and positive in 14 patients (16 lesions). MBI detected 6 breast tumors in 6 patients, comprising 3 known malignancies and 3 additional cancers detected only by MBI (recent screening mammogram was negative). Two high-risk lesions were detected by MBI only (radial scar and atypical papilloma). Positive uptake was detected in 7 benign lesions; 2 led to further diagnostic workup and 5 were determined benign based on review of past mammogram and clinical history. MBI was also positive in one patient with non-Hodgkin lymphoma.

Conclusions MBI may be a valuable additional test for detecting breast cancer in women undergoing MPI. In this population, MBI detected mammographically occult cancers and high-risk lesions, while producing very few false positive results.

Research Support This work was supported by Friends for an Earlier Breast Cancer Test