Abstract
BACKGROUND: The hepatocyte phase (HCP) in gadoxetic acid disodium (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI) plays an important role in the detection and characterization of liver lesions, treatment planning, and liver function evaluation. However, the imaging protocol is complicated and time-consuming. This cross-sectional study aimed to develop a convenient and reproducible protocol for the HCP acquisition in Gd-EOB-DTPA-enhanced MRI. METHODS: A total of 107 patients were prospectively included and assigned to three groups based on Child-Pugh (CP) classification, with 37, 40, and 30 in the non-cirrhosis, CP A, and CP B groups, respectively. Dynamic HCPs were acquired every 5 min after the Gd-EOB-DTPA administration and ended in 25 min in non-cirrhosis patients and 40 min in cirrhotic patients. The HCP acquired 5 min after the initial visualization of the intrahepatic bile duct (IBD) was selected from the dynamic HCPs as the adequate HCP (HCP(proposed)) and the corresponding acquisition time was recorded as Time(proposed). In addition, according to the 2016 Expert Consensus (EC) on the definition of the adequate HCP from the European Society of Gastrointestinal and Abdominal Radiology (ESGAR), the adequate HCP(EC) and the corresponding Time(EC) were also determined from the dynamic HCPs. The hepatic relative enhancement ratio (RER), the contrast-to-noise ratio (CNR), and signal-to-noise ratio (SNR) of hepatic focal lesions in the HCP(EC) and HCP(proposed) images, as well as the Time(EC) and Time(proposed) were compared by the paired t-test for the three groups, respectively. Inter-observer agreement of the determination of the HCP(EC) and HCP(proposed) was compared by the χ(2) test. RESULTS: The RER, CNR, and SNR showed no significant difference between the HCP(EC) and HCP(proposed) in all three groups (all P>0.05). The paired differences between Time(EC) and Time(proposed) were 1.08±3.56 min (P=0.07), 2.88±4.22 min (P<0.001), and 5.83±5.27 min (P<0.001) in the three groups, respectively. Inter-observer agreement of the determination of the HCP(EC) and HCP(proposed) were 0.804 (86/107) and 0.962 (103/107), respectively (χ²=13.09, P=0.001). CONCLUSIONS: The adequate HCP could be acquired 5 min after the initial visualization of the IBD, which could serve as a convenient and reproducible protocol for the HCP imaging.