Sensitivity and specificity of unenhanced MR mammography (DWI combined with T2-weighted TSE imaging, ueMRM) for the differentiation of mass lesions

Abstract

Objective: This study was performed to assess the sensitivity and specificity for malignant and benign mass lesions of a diagnostic approach combining DWI with T2-weighted images (unenhanced MR mammography, ueMRM) and compare the results with contrast-enhanced MR mammography (ceMRM).

Materials and methods: Consecutive patients undergoing histopathological verification of mass lesions after MR mammography without prior breast interventions (contrast-enhanced T1-weighted, T2-weighted and DWI sequences) were eligible for this retrospective investigation. Two blinded observers first rated ueMRM and then ceMRM according to the BIRADS scale. Lesion size, ADC values and T2-weighted TSE descriptors were assessed.

Results: This study examined 81 lesions (27 benign, 54 malignant). Sensitivity of ueMRM was 93% (observer 1) and 86% (observer 2), respectively. Sensitivity of ceMRM was 96.5% (observer 1) and 98.3% (observer 2). Specificity was 85.2% (ueMRM) and 92.6% (ceMRM) for both observers. The differences between both methods and observers were not significant (P > or = 0.09). Lesion size measurements did not differ significantly among all sequences analyzed. Tumor visibility was worse using ueMRM for both benign (P < 0.001) and malignant lesions (P = 0.004).

Conclusion: Sensitivity and specificity of ueMRM in mass lesions equal that of ceMRM. However, a reduced lesion visibility in ueMRM may lead to more false-negative findings.