Esther Han MD, Presenter: Nothing to Disclose

Nathalie Johnson MD, Abstract Co-Author: Nothing to Disclose

Margaret Glissmeyer, Abstract Co-Author: Nothing to Disclose

William Johnson MD, Abstract Co-Author: Nothing to Disclose

Magnetic resonance imaging (MRI) has become increasingly popular as an adjunct to mammography in the diagnosis of breast cancer. Despite its sensitivity in detecting mammographically occult breast lesions, factors such as high cost and patient discomfort make MRI less than ideal. Breast-specific gamma imaging (BSGI) with newer high-resolution cameras has emerged with reports of advantages similar to MRI such as high sensitivity not compromised by breast tissue density. However, few studies have directly compared these two modalities.

A retrospective review of prospectively and retrospectively collected data from a community health system database of patients screened for breast cancer between 2006-2009. Patients who underwent both MRI and BSGI within a 2-month time frame were included in the analysis.

Of 698 patients, 53 met inclusion criteria. The mean age was 55. 38 had abnormal mammograms. 25 (47%) were found to have cancer on pathology. Median tumor size was 0.85 cm. BGSI was positive in 30 patients, of whom 20 had cancer (false positive rate (FP)=36%). MRI was positive in 32, of whom 19 had cancer (FP=46%). BSGI was negative in 23, 5 of whom had cancer (false negative rate (FN)=20%). MRI was negative in 21; 6 had cancer (FN=24%). The positive predictive value (PPV) of BSGI was 67% and negative predictive value (NPV) 78%. The PPV of MRI was 59% and NPV 71%. The sensitivity and specificity of BSGI was 80% and 64%, respectively. The sensitivity of MRI was 76% and specificity 54%. MRI was positive and BSGI negative in 11; of these, 4 had cancer. In 11, BSGI was positive and MRI negative; of these 6 had cancer. In 3 cases (11%), BSGI identified the original tumor previously undetected by other imaging modalities; subsequent MRI was also positive. BSGI detected 3 additional contralateral malignancies and 1 ipsilateral cancer. In no patients was cancer found within 1 year of a negative BSGI. 42% of patients (n=22) had further imaging based on BSGI recommendations; 17% (n=9) underwent subsequent biopsies or surgery.

BSGI results led to further workup and detection of occult malignancies. Negative MRIs without contradictory BSGI results would have led to 6 missed malignant tumors.

BSGI is equivalent to MRI as an adjunct imaging modality in the diagnosis of breast cancer. Similarly, it may be useful for the evaluation of high-risk women or those with dense breasts.

Han, E, Johnson, N, Glissmeyer, M, Johnson, W, Breast Specific Gamma Imaging Is Equivalent to Magnetic Resonance Imaging in the Detection of Breast Cancer.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11015070.html