Tc 99m-Sestamibi scintimammography in the differentiation of benign and malignant breast microcalcifications

The capability of the mammography-scintimammography combination to distingu ish between benign and malignant isolated clusters of breast microcalcifica tions is discussed. Scintimammography using Tc 99m-Sestamibi was performed in 97 women with an isolated cluster of microcalcifications on mammograms. Seventy-two women had final histopathologic diagnoses (24 cancer and 48 ben ign pathology). The other 25 patients had follow-up to 3 years. The results of mammography, scintimammography and mammography-scintimammography combin ation were divided into five groups, based on the suspicion of malignancy. The sensitivity, specificity, false negative fraction, false positive fract ion, predictive positive value, predictive negative value and diagnostic ac curacy were calculated varying the diagnostic threshold. The Receiver Opera ting Characteristic (ROC) statistical technique was employed to compare the diagnostic value of mammography to mamography-scintimammography combinatio n. The area under the ROC curves was calculated by the Wilcoxon statistic w ithout any hypothesis on data distribution. The detected difference between areas under the mammography ROC curve (area = 0.854, standard error = 0.04 9) and mammography-scintimammography ROC curve (area = 0.897, standard erro r 0.033) was statistically significant (P > 0.05, one tail). The area under a ROC curve represents the probability that a randomly chosen diseased or nondiseased subject could be correctly classified. From this point of view this paper demonstrates that, if properly used, scintimammography can add t o mammography in the characterization of an isolated cluster of microcalcif ications, even if it is not able to replace FNAB and core biopsy. (C) 2001 Harcourt Publishers Ltd.