Accuracy of Imaging Techniques in Diagnosing Steatohepatitis and Fibrosis in NAFLD Patients

Non-alcoholic fatty liver disease (NAFLD) is a highly prevalent condition, and when fatty liver is associated with inflammation and hepatocellular injury (steatohepatitis), it can lead to fibrosis, cirrhosis, liver failure and hepatocellular carcinoma. Liver biopsy is the gold standard for NAFLD assessment but has several drawbacks. Several drugs for NASH are now in phase 2-3 trials, and if medical treatments become available, non-invasive tools to identify patients who may benefit from a therapeutic intervention will be strongly needed. Some imaging methods have shown promising potential in fibrosis and NASH diagnosis. This study aims to evaluate the diagnostic accuracy of non-invasive imaging methods, including ultrasound (US) and Magnetic Resonance (MR) techniques, in diagnosing NASH and fibrosis in patients with or at high risk of NAFLD, using liver biopsy as the reference standard. Consecutive patients with a clinical indication for liver biopsy assessment of NAFLD are enrolled in this non-inferiority study. They undergo both a liver US and a multiparametric unenhanced liver MR examination. As reference standard, histological diagnosis of fibrosis and steatohepatitis made according to the fatty liver inhibition of progression (FLIP) algorithm is used. Sensitivity and specificity of imaging parameters alone or in different combinations will be calculated with the aim of finding one or more tests with at least 90% sensitivity/specificity compared to liver biopsy.

Inclusion Criteria: * clinical indication to perform a liver biospy for NAFLD assessment based on all of the following: 1. presence of liver steatosi at ultrasound 2. at least one risk factor for NASH/fibrosis (obesity, or type 2 diabetes mellitus, or metabolic syndrome) 3. increased liver enzymes (at least one of: GOT\>40 U/l, GPT\>49 U/l, GGT\>75 U/l) or high NAFLD fibrosis score (\>0.675), or intermediate NAFLD fibrosis score (between -1.455 and 0.675) and increased liver stiffness at transient elastography (\>7 KPa). * consent to participate in the study Exclusion Criteria: * age \< 18 years * secondary causes of liver steatosis (moderate to severe alcohol consumption, steatogenic drugs) * known diffuse liver diseases other than NAFLD (cirrhosis, viral or autoimmune hepatitis, hemochromatosis, amiloidosis, other) or previous primary or secondary liver neoplasms * contraindications to perform liver biopsy (ascites, platelet count\1.5, PT\>50%, serum bilirubin \>3 mg/dL) * contraindications to perform magnetic resonance (pace-maker, claustrophobia, pregnancy, MR-unsafe metallic implants)