June 3, 2008 - Breast-Specific Gamma Imaging (BSGI) is highly sensitive in detecting the presence of cancer and is as sensitive as MRI for most cancers, according to an article in the June issue of Radiology.
In the study, completed by The George Washington University Medical Center in Washington, D.C., 146 women underwent BSGI and breast biopsy. Study images were assigned scores, and scores were classified as positive or negative and compared with biopsy results. BSGI helped detect cancer in 96.4 percent of the noted malignant lesions; the positive predictive value was 68.8 percent, specificity of 59.5 percent and the negative predictive value for nonmalignant lesions was 94.3 percent. The smallest invasive cancer and DCIS detected were both 1 millimeter, and BSGI helped detect occult cancer not visualized at mammography or ultrasonography in six patients.
Mammography remains the imaging modality of choice for breast cancer screening. The overall sensitivity of mammography has been reported to be 78 to 85 percent; however, the sensitivity of mammography decreases to 42 to 68 percent in women with dense breasts. In addition, the false-positive rate of screening mammography is 15 to 30 percent, leading to many benign findings at biopsy. Limitations in the sensitivity and specificity of screening mammography led to the investigation of adjunct breast Imaging modalities; specifically BSGI, which provides physiological data not obtained with the anatomic Imaging techniques of mammography and ultrasound.
BSGI, molecular imaging of the breast utilizing a high-resolution, small-field-of-view gamma camera, is an increasingly utilized adjunct imaging modality for the diagnosis of breast cancer. Initial studies with this imaging technique report sensitivities similar to MRI with a higher specificity, which is the ability of a test to show when disease is not present.
For more information: www.gwumc.edu