EVALUATION OF PALPABLE BREAST MASSES WITH TC-99M-MIBI - A COMPARATIVE-STUDY WITH MAMMOGRAPHY AND ULTRASONOGRAPHY

We evaluated the feasibility of Tc-99m-methoxyisobutylisonitrile (MIBI ) as a tumour localizing agent in patients with palpable breast masses in comparison with mammography and ultrasonography (US). Forty-one pa tients with palpable masses were studied. An additional 12 women with no palpable breast anomaly also underwent Tc-99m-MIBI breast study. Mu ltiple views were obtained and semiquantitative evaluation was applied . Mammography and US revealed all of the malignant breast masses but d ifferential diagnosis of fibroadenomas could not be achieved. Twenty-f ive of 27 breast carcinomas were detected using Tc-99m-MIBI scintigrap hy. Two patients with invasive lobular carcinoma showed absent MIBI ac cumulation. Eight of 14 axillary lymph-node metastases showed positive uptake (57%). Twelve of 14 patients with pathologically proven benign breast lesions did not demonstrate any MIBI accumulation. Focal MIBI uptake could be observed in two fibroadenomas. The sensitivity and the specificity of semiquantitative MIBI analysis were 93 and 86%, respec tively. Subjective grading offered no additional help in the further d ifferentiation of malignant breast masses. There was no significant di fference between histopathological types of breast carcinomas and upta ke grades. Our results indicate that Tc-99m-MIBI scintigraphy may prov ide additional information in the differentiation of malignant patholo gies from benign lesions in patients with palpable breast anomalies.