Leora Lanzkowsky MD, FRCPC, Presenter: Nothing to Disclose

Deborah Rubin MD, Abstract Co-Author: Nothing to Disclose

Nelda Mullins ARRT, Abstract Co-Author: Nothing to Disclose

The purpose of this study is to compare BSGI and MRI in women with indeterminate findings at mammography and ultrasound.

Patients with indeterminate findings at FFDM and/or ultrasound during clinical evaluation who underwent biopsy of these areas and who had MRI and BSGI are included in this study. BSGI and MRI were performed as deemed necessary by the radiologist such as in patients with newly diagnosed cancer, to exclude additional foci of cancer. MRI with a 1.5 T magnet using a dedicated breast coil and a standard protocol, and BSGI with a small field of view camera (Dilon, 3600) using 25-30 mc of Tc99m was performed. BSGI and MRI were interpreted as positive (BRADS IV or V), negative (BIRADS I or II) or inconclusive (BIRADS 0 or III). Interpreting radiologists had access to all studies at the time of interpretation. Biopsy was performed utilizing the imaging modality as decided by the radiologist.

48 patients with 63 indeterminate lesions were included. Pathology results include: 21 malignant (16 invasive, 5 DCIS), 5 high risk lesions (ADH, LCIS and papilloma) and 37 benign lesions. BSGI and MRI were concordant in 37 lesions: positive in 20 cancers or high risk lesions, negative in one ADH, negative in 6 benign lesions, positive in 5 benign lesions and indeterminate in 5 benign lesions. Of the 26 lesions where BSGI and MRI were discordant, there were 5 cancers or high risk lesions and 21 benign lesions. BSGI was positive in all 5 cancers or high risk lesions while MRI was negative in 2 and indeterminate in 3. Of the 21 benign lesions, BSGI and MRI were negative in 11 and 4 respectively and both resulted in 7 false positive findings, in different patients. MRI was indeterminate in a greater number of benign cases (10 vs. 3 on BSGI). Overall, the sensitivity of BSGI and MRI is 96% and 88% and specificity was 46% and 27% respectively.

BSGI has equivalent sensitivity and better specificity than breast MRI in patients with inconclusive findings at mammography and ultrasound. BSGI has advantages over MRI in that it can be utilized in all patients including those with ferromagnetic implants or renal insufficiency.

BSGI has equivalent sensitivity and better specificity, is more reader and patient friendly, and is less expensive than breast MRI in patients with inconclusive findings at mammography and ultrasound

Lanzkowsky, L, Rubin, D, Mullins, N, Breast Specific Gamma Imaging Compared to Breast MRI in Patients with Inconclusive Mammographic and Ultrasonic Findings.  Radiological Society of North America 2008 Scientific Assembly and Annual Meeting, February 18 - February 20, 2008 ,Chicago IL. http://archive.rsna.org/2008/6009445.html