Gadobenate Dimeglumine–enhanced MR Imaging Breast Vascular Maps: Association between Invasive Cancer and Ipsilateral Increased Vascularity

Abstract

PURPOSE: To retrospectively compare three different doses of gadobenate dimeglumine with a standard dose of gadopentetate dimeglumine for magnetic resonance (MR) imaging evaluation of breast vessels and to evaluate the accuracy of one-sided increased vascularity seen on gadobenate dimeglumine-enhanced MR images as an indicator of ipsilateral breast cancer. MATERIALS AND METHODS: The original study had local ethics committee approval; informed consent was obtained from all enrolled patients. Ninety-five patients known to have or suspected of having breast cancer were randomly assigned to four groups to receive gadobenate dimeglumine at a dose of 0.05, 0.10, or 0.20 mmol per kilogram of body weight or gadopentetate dimeglumine at a dose of 0.10 mmol/kg. T1-weighted gradient-echo MR images were acquired before and 2 minutes after intravenous contrast material injection. Subtracted images were used to obtain maximum intensity projections (MIPs). Two readers blinded to the type and dose of contrast agent administered scored the MIPs obtained in the dose groups for vessel number, length, and conspicuity from 0, which indicated absent or low breast vascularity, to 3, which indicated high breast vascularity. The sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) of one-sided increased vascularity in association with ipsilateral malignancy for 69 histopathologically confirmed lesions (reference standard) were determined after gadobenate dimeglumine-enhanced MR imaging. RESULTS: The mean MIP scores assigned to the gadobenate dimeglumine groups were significantly higher than those assigned to the gadopentetate dimeglumine group (P < or = .044). Histopathologic analysis revealed malignant lesions in 52 of 69 patients examined with gadobenate dimeglumine MR imaging: invasive ductal carcinoma in 45, invasive lobular carcinoma in four, and invasive mixed ductal-lobular carcinoma in three patients. Seventeen patients had benign lesions. Two cases of bilateral invasive cancer with symmetric breast vascular maps were excluded. Thus, the overall sensitivity, specificity, accuracy, PPV, and NPV of one-sided increased vascularity as a finding associated with ipsilateral malignancy were 88% (44 of 50 patients), 82% (14 of 17 patients), 87% (58 of 67 patients), 94% (44 of 47 patients), and 70% (14 of 20 patients), respectively. CONCLUSION: Gadobenate dimeglumine is effective for MR imaging evaluation of breast vessels at doses as low as 0.05 mmol/kg. One-sided increased vascularity is an MR imaging finding frequently associated with ipsilateral invasive breast cancer.