Molecular Breast Imaging May Be Better Than Ultrasound and Mammography for Breast Cancer Detection

Molecular breast imaging (MBI), also known as breast-specific gamma imaging (BSGI), can detect tumors often overlooked by the two most common breast imaging modalities, mammography and ultrasound.

In a recent study, BSGI had the highest overall sensitivity (91%) for breast cancer detection, significantly higher than that of mammography and ultrasound, 74% and 84%, respectively. Moreover, BSGI was more effective than ultrasound in contributing to patient management when the findings of these studies altered the diagnosis provided by mammography.

In this multicenter study of 1042 patients at four institutions, published January 2012 in the American Journal of Roentgenology (AJR), BSGI had an outstanding overall sensitivity of 91% and negative predictive value (NPV) of 96%. The BSGI procedures were performed with a high-resolution gamma camera, the Dilon 6800. For patients who had adjunctive imaging scanning with results discordant from those for mammography, BSGI provided higher diagnostic accuracy than ultrasound (77% vs. 35%). The group of patients with indeterminate mammograms (BI-RADS 0) received the greatest benefit from use of BSGI. For the BI-RADS 0 patients, BSGI was considerably more likely to contribute to patient management than ultrasound, it was less likely to be negative in cancerous lesions, and was less likely to be positive in benign lesions. Interestingly 85% of the patients included in this study had dense breast tissue.

The lead author, Dr. Jean M. Weigert, a radiologist at Bradley Memorial Hospital (New Britain, CT, USA), commented that, “BSGI continuously proves to be a very important diagnostics tool in our facility. In the recently published article BSGI indicated a change in patient management for a greater number of patients, and was typically more effective than ultrasound because of improved specificity and positive predictive values.”

Ultrasound does not involve an exposure to radiation. BSGI involves the injection of a dose to the patient that is comparable with or lower than that of other diagnostic imaging procedures. According to RadiologyInfo.org, a website codeveloped by the American College of Radiology (Reston, VA, USA) and Radiological Society of North America (Oak Brook, IL, USA), “[...] there are no known long-term adverse effects from such low-dose exposure.” Similar to mammography, the benefits of BSGI greatly outweigh the risks due to radiation exposure.

As a follow-up to mammography, BSGI/MBI utilizes the Dilon 6800 gamma camera to help clinicians more precisely differentiate benign from malignant tissue. To perform BSGI/MBI, the patient receives a pharmaceutical tracing agent that is absorbed by all the cells in the body. Because of their increased rate of metabolic activity, cancerous cells in the breast absorb a greater amount of the tracing agent than normal healthy cells and typically appear as dark spots on the BSGI/MBI image.

Dilon Diagnostics’ (Newport News, VA, USA) a brand of Dilon Technologies Inc.) cornerstone product, the Dilon 6800, is a high-resolution, small field-of view gamma camera, optimized to perform BSGI/MBI, a molecular breast imaging procedure that images the metabolic activity of breast lesions through radiotracer uptake.

Related Links:
Bradley Memorial Hospital
Dilon Diagnostics