Breast lesion detection and characterization at contrast-enhanced MR mammography: Gadobenate dimeglumine versus gadopentetate dimeglumine

PURPOSE: To prospectively and intraindividually compare equivalent (0.1 mmol per kilogram of body weight) doses of gaclobenate dimeglumine and gadopentetate dimeglumine for accuracy of detection and characterization of breast lesions at contrast material- enhanced magnetic resonance (MR) mammography. MATERIALS AND METHODS: Ethics committee approval and informed consent were obtained. Twenty-six consecutive women (mean age, 47.8 years) suspected of having a breast tumor at mammography and sonography underwent two identical MR examinations at 1.5 T; examinations were separated by more than 48 hours but less than 72 hours. A T1 -weighted three-dimensional gradient-echo sequence was used, and images were acquired before and at 0, 2, 4, 6, and 8 minutes after randomized injection of gadopentetate dimeglumine or gaclobenate dimeglumine at an identical flow rate of 2 mL/sec. Separate and combined assessment of unenhanced, contrast-enhanced, and subtracted images was per-formed blindly by two readers in consensus. Accuracy for lesion detection was determined against a final diagnosis based on findings at conventional mammography, sonography, and surgery. Sensitivity, specificity, positive and negative predictive values, and overall accuracy for malignant lesion identification were determined against histologic results. Data were analyzed with the McNemar test, proportional odds models, and analysis of variance. RESULTS: MR mammography with gadobenate dimeglumine depicted significantly (P =.003) more lesions (45 of 46) than did that with gadopentetate dimeglumine (36 of 46), and detected lesions were significantly (P <.001) more conspicuous with gadobenate dimeglumine. Confidence for characterization was significantly (P =.031) greater with gadobenate dimeglumine. Comparison of the contrast agents for their ability to help identify malignant lesions revealed significant (P =.02) superiority for gaclobenate dimeglumine: Sensitivity, specificity, positive predictive value, negative predictive value, and overall accuracy for malignant lesion identification were, respectively, 94.7%, 100%, 100%, 80.0%, and 95.6% with gaclobenate dimeglumine and 76.3%, 100%, 100%, 47.1%, and 80.4% with gaclopentetate dimeglumine. Quantitative evaluation of signal intensity-time curves revealed significantly (P <.001) greater lesion enhancement with gaclobenate dimeglumine. CONCLUSION: Detection of breast lesions and accurate identification of malignant lesions at MR imaging are significantly superior with gaclobenate dimeglumine in comparison with gaclopentetate dimeglumine. (c) RSNA, 2005.