Magnetic resonance elastography predicts advanced fibrosis in patients with nonalcoholic fatty liver disease: a prospective study

Nonalcoholic fatty liver disease (NAFLD) is characterized by the presence of hepatic steatosis in individuals who consume little or no alcohol and who have no other identifiable secondary cause of steatosis.1–5. NAFLD is associated with features of metabolic syndrome, including obesity, insulin resistance, hypertension, diabetes, and dyslipidemia.1,4,6,7 It is the most common cause of chronic liver disease (CLD) in the United States.2–5 It affects 80-100 million Americans, of whom 10%-22% may have nonalcoholic steatohepatitis (NASH),8–13 a progressive form that may lead to cirrhosis11,14 and hepatocellular carcinoma.11,15–19 Patients with NASH and especially those with advanced fibrosis are at particularly high risk for these outcomes and require more-intense monitoring and therapy. The current diagnostic gold standard to diagnose advanced fibrosis is liver biopsy.20 However, biopsy is invasive and costly and may be complicated by morbidity and even death.21 Accurate noninvasive objective methods to detect advanced fibrosis in patients with NAFLD are needed, but are not yet commercially available. There are no approved noninvasive tests to diagnose advanced fibrosis. Cytokeratin-18,22 NAFLD fibrosis score,23 and Enhanced Liver Fibrosis (ELF™) Test24 are promising, but may not be sufficiently accurate for routine clinical use.1,25 Ultrasound elastography methods have high (21%-50%) failure rates in NAFLD.26–29 Recent retrospective studies demonstrate that two-dimensional magnetic resonance (MR) elastography (2D-MRE) may be useful in noninvasive diagnosis of advanced fibrosis in NAFLD.30 However, prospective studies of 2D-MRE with paired liver biopsies in well-characterized patients with biopsy-proven NAFLD with a clinical indication for a liver biopsy are needed. Utilizing a prospective cohort study design, we aimed to determine the accuracy of 2D-MRE for noninvasive diagnosis of advanced fibrosis in well-characterized patients with biopsy-proven NAFLD. We also aimed to determine the accuracy of 2D-MRE for noninvasive diagnosis of the presence of NASH, as well as dichotomized stages of fibrosis.