Gadoxetic Acid-Enhanced Hepatobiliary-Phase Magnetic Resonance Imaging for Pyrrolizidine Alkaloid-Induced Hepatic Sinusoidal Obstruction Syndrome and Association with Liver Function.

Hepatic sinusoidal obstruction syndrome (HSOS) can be caused by pyrrolizidine alkaloids(PAs)-containing herbals. In this study, the aim of our study was to investigate the imaging features of PAs-induced HSOS on gadoxetic acid-enhanced magnetic resonance imaging (MRI), susceptibility-weighted imaging(SWI) and T2* weighted imaging (T2* WI). We analyzed medical records and MR images of 28 PAs-induced HSOS patients enrolled from Feb, 2013, to Apr, 2017. Abnormal liver function was observed in most of the PAs-induced HSOS patients. Heterogeneity of liver parenchyma in hepatobillary phase (HBP) of gadoxetic acid-enhanced MR scan was observed in 100% of the PAs-induced HSOS patients. Distributional patterns of heterogeneous hypointensity were multifocal distribution (mild) in 4 patients (14.29%), multifocal distribution (severe) in 15 cases (53.57%), and diffuse distribution in 9 patients (32.14%). Hypointense in SWI and T2WI was observed in the patients of PAs-induced HSOS, and the distribution of hypointense in SWI and T2WI was similar to that of portal-venous phase of MR scan. The severity of heterogeneous hypointensity scored by volume fraction in hepatobillary phase of gadoxetic acid-enhanced MRI was positively correlated with PT and INR, the severity of hypointensity in HBP was a risk factor of death events. In conclusion: Heterogenous hypointensity of liver parenchyma was an imaging sign of hepatobillary phase in gadoxetic acid-enhanced MRI; thus, it will provide evidences for the diagnosis of PA-induced HSOS.