Scintigraphy of the female breast with Tc-99m-DTPA: a prospective blind evaluation

Following a report on the use of Tc-99m-diethylenetriamine pentaacetic acid (Tc-99m-DTPA) for detection of malignant breast tumors we compared this method with other diagnostic aids such as mammography and cytology. Among 160 women referred to our department for diagnosis, 166 examinations were performed (six patients had bilateral lesions); the final diagnosis of the breast lesion was established as malignant in 62 cases and benign in 104 cases. The scintigraphic image was reported malignant if an area of focal uptake observed on the scan 30 minutes after injection of the tracer persisted or became more intense on the 2-hour scintigram. All other uptake patterns were considered benign. For this examination we obtained a sensitivity of 75% and a specificity of 91%. For mammography, sensitivity was 90% and specificity was 82%. The lower false-positive results of scintigraphy may serve to confirm the benignancy of doubtful mammographic findings, for when both examinations suggest a benign lesion, the combined imaging procedure is a useful means of excluding cancer (sensitivity 96%, predictive value 98%). It is concluded that in all other cases Tc-99m-DTPA breast scintigraphy is of limited value.