Noninvasive imaging biomarker assessment of liver fibrosis by elastography in NAFLD

NAFLD is a global epidemic. The prevalence of NAFLD is 20-30% in North America, northern Europe, Australia, Japan, India and China. It is crucial that patients with NAFLD receive an assessment for their risk of advanced fibrosis, which increases the risk of hepatocellular carcinoma and other complications of cirrhosis. Risk stratification that is efficient, cost-effective, patient-centred and evidence-based is one of the most important issues facing clinicians who care for those with liver disease. Given patients' preference to avoid liver biopsy, noninvasive alternatives to assess liver fibrosis are in high demand. The most accurate noninvasive methods are based on liver elastography. Research on these techniques - which include vibration-controlled transient elastography (VCTE), magnetic resonance elastography (MRE), shear-wave elastography and acoustic radiation force impulse - has proliferated. Unfortunately, the literature has not kept pace with clinical practice. There is limited guidance for how clinicians should anticipate and manage the pitfalls of these tests. Furthermore, guidance is unavailable for clinicians regarding the optimal incorporation of VCTE, MRE or the emerging elastographic techniques into their clinical strategy, particularly for patients with NAFLD. In this Review, we summarize the available evidence, highlight gaps to address in further research and explore optimization of these techniques in clinical practice.