Magnetic Resonance Imaging Features In Pyrrolizidine Alkaloid-induced Hepatic Sinusoidal Obstruction Syndrome

Objective: To analyze the features of magnetic resonance imaging(MRI)in pyrrolizidine alkaloid(PAs)-induced hepatic sinusoidal obstruction syndrome(HSOS),to collect clinical records and laboratory data,and to investigate the association of the proportion of hepatic heterogeneous hypoattenuation area with liver function.Methods: Retrospectively analyze 39 PAs-induced HSOS patients enrolled in our study from Sep 2010 to May 2016.Baseline information,medical records,laboratory data and MR images were collected.Two experienced radiologists independently reviewed the MR images of all the 39 patients,they were blinded to clinical informantion;and summarize each patient’s information in the designed excel table.Results:1、Most patients of PAs-induced HSOS were observed with a disordered liver function.2、The consensus between the two observers was excellent with intraclass correlation coefficients(ICC)of 0.982.The common findings of MR image in PAs-induced included: ascites(100%),hepatomegaly(61.54%),gallbladder wall thickening(92.31%),periportal edema(97.44%),pleural effusion(58.97%),heterogeneous hypointensity(100%),narrowing of right hepatic vein(61.54%),invisible contrast materials in right hepatic vein(38.46%),narrowing of inferior vena cava(97.44%).Of these signs,hypointense heterogeneity in portal-veneous phase was a distinct feature of PAs-induced HSOS.Common pattern of inhomogeneous enhancement was “claw-shaped” enhancement around hepatic vein in most of PAs-induced HSOS patients.Hypointense in SWI and T2*WI imaging was observed in PAs-induced HSOS,and the distribution of hypointense in SWI and T2*WI imaging was consistent with that of heterogeneous hypointensity on portalvenous phase of dynamic contrast-enhanced MRI scan.3、On Pearson correlation analysis,the severity of heterogeneous hypointensity scored by the proportion of area in PAs-induced HSOS was statistically significantly correlated with liver damage index ALT(P=0.02),AST(P=0.003),hepatic synthetic function parameter ALB(P=0.039),PT(P=0.012),INR(P=0.013)and an non-invasive marker of fibrosis(APRI)(P=0.011).Conclusion: The patients with PAs-induced hepatic sinusoidal obstruction syndrome displayed distinct features in MRI scan;there is an asscociation between the proportion of hepatic heterogeneous hypoattenuation area and liver function,and the more is the proportion of hepatic heterogeneous hypoattenuation area,the more severe is the liver function;thus MRI will provide an effective strategy in differentiating PAs-induced HSOS from other liver diseases.