Author information
1
Liver Imaging Group,Department of Radiology, University of California San Diego , San Diego, CA , USA.
2
Department of Radiology,Washington University School of Medicine, Washington University, 510 S Kingshighway , St. Louis , MO.
Abstract
Hepatic steatosis is a frequently encountered imaging finding that may indicate chronic liver disease, the most common of which is nonalcoholic fatty liver disease (NAFLD). NAFLD is implicated in the development of systemic diseases and its progressive phenotype, nonalcoholic steatohepatitis (NASH), leads to increased liver-specific morbidity and mortality. With the rising obesity epidemic and advent of novel therapeutics aimed at altering metabolism, there is a growing need to quantify and monitor liver steatosis. Imaging methods for assessing steatosis range from simple and qualitative to complex and highly accurate metrics. Ultrasound may be appropriate in some clinical instances as a screening modality to identify the presence of abnormal livermorphology. However, it lacks sufficient specificity and sensitivity to constitute a diagnostic modality for instigating and monitoring therapy. Newer ultrasound techniques such as quantitative ultrasound show promise in turning qualitative assessment of steatosis on conventional ultrasound into quantitative measurements. Conventional unenhanced computed tomography (CT) is capable of detecting and quantifying moderate to severe steatosis but is inaccurate at diagnosing mild steatosis and involves the use of radiation. Newer CT techniques, like dual-energy CT, show potential in expanding the role of CT in quantifying steatosis. MRI PDFF is currently the most accurate and precise imaging biomarker to quantify liver steatosis. As such, PDFF is the most appropriate noninvasive endpoint for steatosis reduction in clinical trials and therapy response assessment.