All patients underwent MRI examinations using a 3T Magnetom Trio Tim (Siemens Medical Solutions), Intera Achieva or Ingenia (Philips Medical Systems), or Discovery MR750w (GE Medical Systems) MRI scanner [24 (link)]. Dynamic MRI studies of the liver were performed using 10 mL of intravenous gadoxetate disodium (Primovist; Bayer AG) at a rate of 1 mL/sec, followed by 20 mL of 0.9% saline chaser at the same rate (Spectris Solaris MR Injection System; Medrad). T1-weighted three-dimensional gradient-echo imaging was performed before contrast injection and in the arterial phase (18 seconds after aortic enhancement using the bolus tracking method), portal venous phase (60 seconds), delayed phase (90 seconds) transitional phase (150 seconds), and hepatobiliary phase (20 minutes after contrast agent injection).
Other MRI sequences included an axial dual-echo T1-weighted breath-hold gradient echo sequence for acquisition of in-phase and out-of-phase images, an axial respiratory-triggered turbo spin-echo T2-weighted sequence with fat saturation, an axial half-Fourier acquisition single-shot turbo spin-echo T2-weighted sequence with fat saturation, and diffusion-weighted imaging with respiratory-triggered single-shot echo planar imaging sequences with b values of 0, 50, 400, and 800 sec/mm2 or 50, 400, and 800 sec/mm2.