Endocrinol Metab.  2020 Jun;35(2):243-259. 10.3803/EnM.2020.35.2.243.

Noninvasive Evaluation of Nonalcoholic Fatty Liver Disease

• Lee DH

• KMID: 2503255
• DOI: http://doi.org/10.3803/EnM.2020.35.2.243

Abstract

Nonalcoholic fatty liver disease (NAFLD) is the most prevalent liver diseases and can progress to advanced fibrosis and end-stage liver disease. Thus, intensive research has been performed to develop noninvasive methods for the diagnosis of nonalcoholic steatohepatitis (NASH) and fibrosis. Currently, no single noninvasive tool covers all of the stages of pathologies and conditions of NAFLD, and the cost and feasibility of known techniques are also important issues. Blood biomarkers for NAFLD may be useful to select subjects who need ultrasonography (US) screening for NAFLD, and noninvasive tools for assessing fibrosis may be helpful to exclude the probability of significant fibrosis and to predict advanced fibrosis, thus guiding the decision of whether to perform liver biopsy in patients with NAFLD. Among various methods, magnetic resonance-based methods have been shown to perform better than other methods in assessing steatosis as well as in detecting hepatic fibrosis. Many genetic markers are associated with the development and progression of NAFLD. Further well-designed studies are needed to determine which biomarker panels, imaging studies, genetic marker panels, or combinations thereof perform well for diagnosing NAFLD, differentiating NASH and fibrosis, and following-up NAFLD, respectively.

Keyword

Evaluation; Non-alcoholic fatty liver disease; Liver steatosis; Fibrosis; Biomarkers

Figure

• 

  Fig. 1 Diagrams of spectrum obtained by hepatic proton magnetic resonance spectroscopy (1H-MRS). Proton spectra obtained from normal (A) and fatty (B) livers show resonance peaks from water and triglyceride (TG), with boxes highlighting the dominant lipid peaks from the resonance of methyl (−CH3) protons and methylene (−(CH2)n−) in the TG molecule along the frequency domain. ppm, parts per million.

• 

  Fig. 2 Hepatic magnetic resonance imaging (MRI)-proton density fat fraction (PDFF). Liver MRI-PDFF study in a patient with nonalcoholic fatty liver disease (NAFLD) showing. (A, B) T1-weighted magnetic resonance images showing the automatic capturing of the liver and (C) the summary of results that shows PDFF of the whole liver (13.2%) as well as R2* value (as a marker for liver iron content). R2* values of <126 S−1 are normal at 3T scanner examination [41].

• 

  Fig. 3 Hepatic magnetic resonance elastography (MRE). Liver MRE study in a patient with nonalcoholic fatty liver disease showing: (A) magnitude image, (B) phase contrast, (C) wave image, (D, E) gray and color scale stiffness maps (elastograms), and (F) color stiffness map with overlayed confidence map.

• 

  Fig. 4 Algorithm for nonalcoholic fatty liver disease (NAFLD) evaluation. Calculations: NFS=−1.675+0.037×age (yr)+0.094×BMI (kg/m2)+1.13×IFG/DM (yes=1, no=0)+0.99×AST/ALT ratio–0.013×platelet (×109/L)–0.66×albumin (g/dL); FIB-4=(age×AST)/[PLT(×109/L)×(√ALT)]; APRI=[AST (IU/L)/ULN/PLT(×109/L)]×100. MS, metabolic syndrome; IR, insulin resistance; DM, diabetes mellitus; US, ultrasonography; FIB-4, fibrosis-4; NFS, NAFLD Fibrosis Score; APRI, AST to platelet ratio index; ELF, enhanced liver fibrosis; VCTE, vibration-controlled transient elastography; MRE, magnetic resonance elastography. aHigher cutoffs for patients aged >65 years; bAffected by body factors and suggested cutoff values have been variable; cFurther validation is required.

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