Diagnostic performance characteristics of architectural features revealed by high spatial-resolution MR imaging of the breast.

OBJECTIVE: Our objective was twofold: to determine which architectural features revealed by high spatial-resolution MR imaging of the breast contribute to diagnostic accuracy and to evaluate the diagnostic performance characteristics of those architectural features. MATERIALS AND METHODS: Eligible patients with suspicious mammographic or palpable findings or both underwent MR imaging. Ninety-three patients whose MR images revealed lesions that corresponded to the mammographically visible or palpable findings were included in the study. Patients were examined with sagittal T1-weighted spin-echo MR imaging, fat-saturated T2-weighted fast spin-echo MR imaging, and dynamically enhanced fat-saturated fast gradient-echo MR imaging. All patients underwent subsequent excisional biopsy or cyst aspiration. Lesions were identified initially by an experienced radiologist who was aware of the patient's clinical or mammographic information. Two radiologists who were unaware of the patients' histories and who had less experience in MR imaging of the breast then independently evaluated each lesion for the architectural-features and predicted each lesion's potential for malignancy. RESULTS: Architectural features that were highly predictive of benign disease included smooth or lobulated borders (97-100%), the absence of mass enhancement (100%), and enhancement that was less than the enhancement of surrounding breast fibroglandular tissue (93-100%). Nonenhancing internal septations were specific for the diagnosis of fibroadenoma. Architectural features that were highly predictive of malignant disease included spiculated borders (76-88%) and peripheral rim enhancement in the presence of central lesion enhancement (79-92%). CONCLUSION: Architectural features revealed by high spatial-resolution MR imaging of the breast can help distinguish benign from malignant disease.