Additional Breast Ultrasound Examinations in Clustered Calcifications: for Improving Diagnostic Performance

Abstract

Purpose: We wanted to determine whether additional breast ultrasound examinations are needed for patients who have clustered calcifications found by mammography for the detection of breast carcinomas. Methods: We performed targeted ultrasound examinations in 125 consecutive patients who had clustered calcifications found by mammography. Forty-eight pathologically proven patients with 61 breast lesions were included in this study (26 invasive carcinomas, 10 ductal carcinomas in situ and 25 benign diseases). Two breast radiologists evaluated the mammography and the ultrasound findings and they graded the probability of malignancy by consensus as follows: definitely benign 1, probably benign 2, probably malignant 3, and definitely malignant 4. The diagnostic performance values, including the sensitivity, specificity, accuracy, positive predictive value and negative predictive value, for mammography and additional ultrasound were compared using McNemar's test and receiver operating characteristic (ROC) analysis. On the ROC analysis, areas under the ROC curves (AUC) and 95% confidence intervals (CI) were obtained. Results: The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value for making the diagnosis of breast carcinoma by mammography were 88.9%, 12.0%, 57.4%, 59.3%, and 42.9% and those for additional ultrasound were 94.4%, 64.0%, 82.0%, 79.1%, and 88.9%, respectively. The differences of specificity and accuracy were statistically significant (p=0.0003). On the ROC analysis, ACU were significantly different between mammography (AUC=0.586, 95% CI=0.453-0.711) and ultrasound (AUC=0.823, 95% CI=0.704-0.909) (p=0.003). Clustered calcifications with associated masses or ductal changes on additional breast ultrasound had high frequency of malignancies, 79% or 73%. In addition, 87% of malignant masses were invasive carcinomas and 45% of malignant ductal changes were ductal carcinomas in situ. Conclusion: Additional breast ultrasound examinations for the lesions with clustered calcifications on mammography can improve the diagnostic performance and significantly contribute to the specificity and accuracy of a diagnosis of breast carcinoma. In addition, the ultrasound features may predict the pathologic findings such as benignity or malignancy and invasive carcinoma or ductal carcinoma in situ.