Magnetic resonance assessment of portal hypertension and liver function

In liver disease, measurements of portal hypertension and liver function can predict clinical outcomes and help guide management, but are either invasive or lack accuracy. This thesis explores magnetic resonance imaging (MRI) techniques with gadoxetic acid administration to assess portal hypertension and liver function non-invasively. This adds to the existing capabilities of multiparametric MRI to assess liver fibrosis, fat and iron. Spleen extracellular volume fraction (ECV) and platelet count to spleen volume ratio identified portal hypertension accurately (both 0.79 area under the receiver operator curve (AUROC)). A combination of spleen T1 and spleen diameter identified oesophageal varices needing treatment (VNTs) in patients with compensated advanced chronic liver disease (cACLD) with the highest accuracy (AUROC 0.87) of all markers tested and could save 66% of screening endoscopies for VNTs without missing any VNTs. Liver T1 reduction with gadoxetic acid (%rT1) correlated well with serum-based liver function markers and clinical scores and identified patients with impaired liver function with AUROC 0.86. MRI-based markers of portal hypertension (spleen ECV; platelet count/spleen diameter ratio; spleen T1 x spleen diameter) and %rT1 were predictive of liver-related clinical outcomes in patients with cirrhosis, who are at high risk of complications, but did not add to the predictive ability of age, albumin, sodium and APRI. In conclusion, MRI provides accurate markers of portal hypertension and liver function. Of particular importance, spleen T1 and spleen diameter criteria could be used to avoid more screening endoscopies in cACLD than any other VNT exclusion criteria reported to date. Although prognostic in the high risk cohort studied here, the MRI markers of portal hypertension and liver function do not surpass the prognostic value of simpler measures.