Diagnosis of Non-alcoholic Fatty Liver Disease (NAFLD): Current Concepts

Abstract

Nonalcoholic fatty liver disease (NAFLD) ranges from simple hepatic steatosis to non-alcoholic steatohepatitis (NASH) and cirrhosis. The majority of NAFLD patients do not progress to NASH and their morbidity risk is low. However, clinical and economic burden of the disease is considerable since the prevalence of the disease is estimated as high as 25% of the general population. Liver biopsy remains the current gold standard for diagnosis, despite limitations regarding sampling variability, invasive nature, and high cost. However, numerous non-invasive biomarkers, including mainly serum markers or imaging modalities, intend to detect the presence of steatosis, NASH or advanced fibrosis. To date, ultrasound is suggested as first-line screening tool for defining steatosis in a selected population, while diagnosis of NAFLD requires exclusion of other chronic liver disease etiology or other steatosis causes. A crucial step in the management of NAFLD patients is the identification of advanced fibrosis, which may be reliably excluded by using NAFLD-Fibrosis score or FIB-4 score or by performing transient elastography. The most robust modalities implement Magnetic Resonance technology and manage to accurately quantify steatosis or identify fibrosis stage, but are not yet applicable in routine practice. The most challenging endpoint has proved to be a non-invasive diagnosis of NASH since no reliable biomarkers have been found to detect or predict inflammation in NAFLD. Lately, research focuses on validating existing markers as robust diagnostic tools for clinical use and investigating novel experimental markers of disease. Current strategies concepts aim to safely diagnose NAFLD patients, aid drug development and finally, guide personalised treatment.

Exenatide improves cardiovascular risk factors in obese patients with type 2 diabetes mellitus: a prospective study

“…Exenatide is not widely investigated in patients with NAFLD and T2DM. Limited studies showed promising effects of exenatide on NAFLD [10,27]. We showed in our trial that AST, ALT and GGT levels decreased with exenatide treatment, and we also showed that the liver craniocaudal diameter decreased with exenatide treatment significantly.…”

<p>SGLT-2 inhibitors as promising therapeutics for non-alcoholic fatty liver disease: pathophysiology, clinical outcomes, and future directions</p>

“…25 Several non-invasive imaging methods have been developed to evaluate the degree of hepatic steatosis. Ultrasonography is a screening technique that typically shows a diffuse increase in echogenicity in fatty liver; 26 it is not as specific or sensitive compared to other imaging techniques especially in morbidly obese patients. 27 Transient elastography detects and quantifies steatosis and fibrosis by measuring ultrasound signals emitted from the FibroScan probe.…”

“…27 Transient elastography detects and quantifies steatosis and fibrosis by measuring ultrasound signals emitted from the FibroScan probe. 26 Magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) are considered the most accurate imaging modalities for estimation of intrahepatic fat content. 15,16 Scoring systems have also been developed for estimation of the degree of liver fibrosis.…”

“…15,16 Scoring systems have also been developed for estimation of the degree of liver fibrosis. Frequently used are the FIB-4 index (Fibrosis Index Based on 4 factors: using age, AST, ALT, and platelet levels), 26 the NAFIC score (NASH Ferritin and type IV collagen 7S: using levels of ferritin, fasting insulin, and T4C7S [Type 4 Collagen 7S]), 28 or the NFS score (NAFLD Fibrosis Score: using age, BMI, AST/ ALT ratio, serum glucose, and albumin). 24 The above information can also be used to select patients in whom liver biopsy is needed for further classification, management, and follow-up.…”

Hepatocellular Carcinoma and Non-Alcoholic Fatty Liver Disease: A Step Forward for Better Evaluation Using Ultrasound Elastography

“…Young modulus, E, is measured in kilopascals (kPa), and it corresponds to the liver stiffness, such that a higher value indicates a stiffer tissue. Liver stiffness range between 1.5 to 75 kPa [ 40 , 41 ] with normal values at around 4.5 to 5.5 kPa in the healthy population [ 35 ]. The equipment displays the median of the measured Young’s modulus, the interquartile range (IQR), the interquartile range/median ratio (IQR/M) after 10 conclusive measurements, and also the success rate of the measurements (SR) [ 31 ].…”