Magnetic Resonance Imaging Acquisition

All patients were scanned using a 1.5T system (Magnetom Espree Pink; Siemens, Erlangen, Germany) equipped with an 8-channel phased-array surface coil for the breast. Conventional scans were carried out using the following parameters: axial T1 weighted imaging 3-dimensional (3D) nonfatsuppressed: (repetition time/echo time [TR/TE], 8.7/4.7 ms; acquired slice thickness, 1.1 mm); axial T2WI plus fat saturation: (TR/TE, 2900/60 ms; slice thickness, 4.0 mm). Dynamic contrast-enhanced MRI used a fast small-angle excitation three-dimensional imaging (3D-FLASH) sequence and fat-saturated axial T1 weighted imaging: (TR/TE, 4.5/1.6 ms, acquired slice thickness, 1.1 mm). Dynamic contrast-enhanced MRI was started after intravenous administration of 0.1 mmol/kg Gd-DTPA (Magnevist; Bayer, Berlin, Germany), followed by 30 mL of normal saline for washing at a flow rate of approximately 2.0 mL/s. Digital subtraction was simultaneously performed automatically at the same time. The scanning range included bilateral breast tissue, the front of the same level of the thorax, and bilateral armpits.