Molecular Breast Imaging in Patients with Suspicious Calcifications.

Area of Science:

• Nuclear medicine
• Breast imaging
• Oncology

Background:

• Mammography is standard for detecting breast calcifications.
• Molecular breast imaging (MBI) uses radiopharmaceuticals to visualize functional uptake in the breast.
• Accuracy of MBI for suspicious calcifications requires evaluation.

Purpose of the Study:

• To assess the accuracy of MBI in patients with suspicious mammographic calcifications.
• To determine if MBI can help avoid unnecessary biopsies.

Main Methods:

• Prospective enrollment of women scheduled for stereotactic biopsy of mammographic calcifications.
• Prebiopsy MBI performed using Tc-99m sestamibi and a cadmium zinc telluride gamma camera.
• Biopsy of positive findings on either mammography or MBI; excision of malignant findings.

Main Results:

• Of 76 calcifications biopsied, 24 (32%) were malignant (20 DCIS, 4 invasive).
• MBI was positive in 17% of calcifications, detecting 50% of DCIS and 50% of invasive cancers.
• MBI identified additional occult cancers in 2 of 6 patients (33%), including contralateral DCIS.

Conclusions:

• MBI has insufficient negative predictive value to avoid biopsies for suspicious calcifications.
• MBI can detect mammographically occult breast cancer in women undergoing biopsy.
• Negative MBI findings should not be used to avoid biopsy of suspicious calcifications.