BSGI effective in detecting malignant or high-risk lesions in patients with negative mammographic findings

Breast-Specific Gamma Imaging (BSGI) significantly contributes to the detection of malignant or high-risk lesions in patients with negative or indeterminate mammographic findings, according to results of a multicenter study presented today at the annual meeting of the Radiological Society of North America (RSNA).

In this retrospective study, BSGI was conducted as an adjunct diagnostic imaging modality at four institutions and was compared to biopsy or follow up imaging. The biopsy results were classified as positive (malignancy or high-risk lesions such as ADH, ALH, LCIS) or negative (benign conditions not requiring additional intervention). The imaging studies were classified as positive (BI-RADS 4 or 5), negative (BI-RADS 1 or 2), or indeterminate (BI-RADS 0 or 3).

In this retrospective study, BSGI was utilized in a total of 2,004 patients. Pathology or follow-up imaging was available for 1,042 cases resulting in 250 positive and 792 negative findings. BSGI demonstrated an overall sensitivity of 91 percent and specificity of 77 percent.

Compared to mammography, which demonstrated a sensitivity of 71%, BSGI improved the detection of malignant and high-risk lesions especially when used in the clinical work up of patients with negative or indeterminate mammograms. The authors determined the contribution of BSGI to be more cost effective than other, more expensive imaging techniques such as MRI or Positron Emission Mammography (PEM) with a cost of $303.34 per procedure and disease diagnosis for every $2,431.57 spent in this study.

BSGI for the study was conducted using a Dilon 6800 Gamma Camera, a high-resolution, small field-of-view gamma camera, optimized to perform BSGI. With BSGI, the patient receives a pharmaceutical tracing agent that is absorbed by all the cells in the body. Due to their increased rate of metabolic activity, cancerous cells in the breast absorb a greater amount of the tracing agent than the normal surrounding tissue and generally appear as "hot spots" on the BSGI image.

Principle author of the study, Dr. Margaret Bertrand, Director of Breast Imaging at Solis Bertrand Breast Center in Greensboro, N.C. said that, "In our experience, BSGI has been extremely useful in efficiently, economically, and accurately augmenting breast imaging in those patients that really need it the most, those with complicated or indeterminate mammograms."