Results of a multicenter patient registry to determine the clinical impact of breast-specific gamma imaging, a molecular breast imaging technique.

OBJECTIVE. Molecular breast imaging techniques, such as breast-specific gamma imaging, are increasingly being used as adjunctive diagnostic technologies to mammography and ultrasound. This multicenter clinical patient registry was designed to quantify the impact of this modality on the management of the breast patient population in clinical practice and to identify the subgroups of patients benefiting from its use. MATERIALS AND METHODS. There were 1042 patients included in this analysis, and breast-specific gamma imaging typically was recommended when the patient had at least two of the following indications: equivocal or negative mammogram or sonogram and an unresolved clinical concern; personal history of breast cancer or current cancer diagnosis; palpable masses negative on mammographic and sonographic examination; radiodense breast tissue; or high risk for breast cancer. Pathologic analysis or follow-up imaging, if biopsy was not conducted, was used as the reference standard, and lesions were classified as positive (i.e., malignant or high risk) in 250 cases and as negative (i.e., benign) in 792 cases. RESULTS. Breast-specific gamma imaging was positive in 408 patients (227 malignant or high-risk lesions requiring additional intervention), negative in 634 patients (23 with malignant or high-risk lesions), and indeterminate in 69 patients (all benign lesions). Breast-specific gamma imaging had an overall sensitivity of 91% and specificity of 77%. CONCLUSION. Breast-specific gamma imaging significantly contributed to the detection of malignant or high-risk lesions in patients with negative or indeterminate mammographic findings, and it provided improved management when compared with ultrasound.