Image Acquisition
All the MR images were acquired using a United Imaging MR790 3.0 T scanner (Shanghai, China). T1 weighted images were acquired with a 3D fast spoiled gradient-echo sequence; the parameters were: TR = 6.9 ms, TE = 2.9 ms, flip angle = 9°, inversion time = 1000 ms, field of view = 256 × 240 mm, voxel size = 1 × 1 × 1 mm