TC-99M TETROFOSMIN SCINTIGRAPHY AS AN ADJUNCT TO PLAIN-FILM MAMMOGRAPHY IN PALPABLE BREAST-LESIONS

Aim: To investigate the use of Tc-99m tetrofosmin as a breast imaging agent and to compare results of Tc-99m tetrofosmin scintimammography w ith plain-film mammography and pathological outcome. Patients and Meth ods: Forty-four patients (mean age, 51 years; range 26-79 years) with a palpable breast mass requiring fine needle aspiration biopsy (FNAB) were prospectively studied, All patients had Tc-99m tetrofosmin scinti mammography. Patients over 35 years of age had two view mammography pe rformed on the same day, FNAB was performed within 2 weeks of imaging, and patients referred for surgery as appropriate. Results of scintigr aphy and plain-him mammography were correlated with pathological outco me. Results: Of the 44 patients, 21 had biopsy proven malignancy while 23 had benign lesions. Of the 21 patients with carcinoma, 20 (95.2 %) had positive Tc-99m tetrofosmin scintimammography while 21 (91.3 %) o f the 23 patients with benign histology had negative scintigraphy, The sensitivity of scintimammography was 95.24%, the specificity was 91.3 %, with a positive predictive value of 90.9% and a negative predictive value of 95.45%, Thirty-eight patients had two view mammography perfo rmed (six patients were <35 years of age), Of these 38 patients, 21 ha d biopsy proven malignancy white 17 had benign histology tall patients <35 years of age had benign histology). Of the 21 patients with malig nancy, plain-film mammography was suspicious for malignancy in 17 (81% ) while four were reported as benign, Of the 17 with benign disease, 1 4 patients (82.4%) had benign appearances on plain-film mammography wh ile three (18%) had one or more findings suspicious for malignancy. Th e sensitivity of plain-film mammography in our group was 81%, with a s pecificity of 82.4%, a positive predictive value of 85% and a negative predictive value of 77.8%, Tc-99m tetrofosmin scintimammography corre ctly characterized all seven lesions where mammographic evaluation was limited because df dense breast parenchyma or previous surgery and/or radiotherapy. Conclusion: Tc-99m tetrofosmin scintimammography is an accurate. well tolerated and non-invasive method of differentiating be nign from malignant palpable breast lesions. Negative Tc-99m tetrofosm in scintimammography excludes malignancy with a high degree of confide nce while false-positive scintigraphy can occur in cases of proliferat ive dysplasia and hypercellular fibroadenoma. Tc-99m tetrofosmin scint imammography is particularly useful when plain-film mammography is ind eterminate or limited in patients with dense breasts or a history of p revious surgery and/or radiotherapy.