MRI protocol
MR
DCE-MRI examination was performed on a 3.0T MR scanner (Magnetom Verio, Siemens Medical Solutions, Erlangen, Germany) with a 16-channel phased-array breast coil. The patient was placed in the prone position with both breasts naturally suspended in the double coil, and their head was positioned toward the machine. The MRI examination protocols were as follows: 3D positioning scan, cross-sectional turbo inversion recovery magnitude (TIRM) sequence (TR = 4000 ms, TE = 70 ms, slice thickness = 4 mm, FOV = 34 cm × 34 cm, matrix = 448 × 448, NEX = 2); bilateral sagittal T2-weighted imaging (T2WI, fat suppression) with the following parameters: TR = 4650 ms, TE = 85 ms, slice thickness = 4 mm, layer space = 1.0 mm, FOV = 20 cm × 20 cm, matrix = 320 × 224, NEX = 4.3D T1WI Dyna View sequences using low-temporal-resolution DCE-MRI scans were conducted with the following parameters: TR = 4.51 ms, TE = 1.61 ms, slice thickness = 1 mm, FOV = 34 cm × 34 cm, matrix = 448 × 448, and NEX = 1. The sequence had a temporal duration of 60 s and a total of 7 phases (1 pre-contrast and 6 post-contrast phases). The overall scan time was 7 min 9 s. The high-temporal-resolution DCE-MRI scans were obtained using the following parameters: TR = 4.43 ms, TE = 1.38 ms, slice thickness = 2 mm, FOV = 30 cm × 30 cm, matrix = 224 × 224, NEX = 1, and flip angle = 15°. The temporal duration was 11 s, and there were 27 phases (1 pre-contrast and 26 post-contrast phases) in total. The overall scan time was 5 min 3 s.The contrast agent gadopentetate dimeglumine (Omniscan, GE Healthcare) at a dose of 0.1 mmol/kg was administered by intravenous bolus injection using a double-cylinder high-pressure injector (MR injection system) at a flow rate of 2.0 ml/sec, followed by a 10 ml saline flush.