Review article: the diagnosis of non‐alcoholic fatty liver disease – availability and accuracy of non‐invasive methods

Abstract

Summary Background Non‐alcoholic fatty liver disease (NAFLD) encompasses a wide spectrum of clinical conditions, actually representing an emerging disease of great clinical interest. Currently, its diagnosis requires liver biopsy, an invasive procedure not free from potential complications. However, several non‐invasive diagnostic strategies have been proposed as potential diagnostic alternatives, each with different sensitivities and accuracies. Aim To review non‐invasive diagnostic parameters and tools for NAFLD diagnosis and to formulate a diagnostic and prognostic algorithm for a better classification of patients. Methods A literature search was carried out on MEDLINE, EMBASE, Web of Science and Scopus for articles and abstracts in English. The search terms used included ‘NAFLD’, ‘non invasive method and NAFLD’, ‘transient elastography’ and ‘liver fibrosis’. The articles cited were selected based on their relevancy to the objective of the review. Results Ultrasonography still represents the first‐line diagnostic tool for simple liver steatosis; its sensitivity could be enhanced by the complex biochemical score SteatoTest. Serum cytokeratin‐18 is a promising and accurate non‐invasive parameter (AUROCs: 0.83; 0.91) for the diagnosis of non‐alcoholic steatohepatitis (NASH). The staging of liver fibrosis still represents the most important prognostic problem: the most accurate estimating methods are FibroMeter, FIB‐4, NAFLD fibrosis score (AUROCs: 0.94; 0.86; 0.82) and transient elastography (AUROC: 0.84–1.00). Conclusions Different non‐invasive parameters are available for the accurate diagnosis and prognostic stratification of non‐alcoholic fatty liver disease which, if employed in a sequential algorithm, may lead to a reduced use of invasive methods, i.e. liver biopsy.

Positron emission tomography probe demonstrates a striking concentration of ribose salvage in the liver

“…However, metabolic syndrome is associated with interrelated and progressive liver pathologies, including nonalcoholic fatty liver disease (NAFL), nonalcoholic steatohepatitis, liver fibrosis, and hepatocellular carcinoma (34). Noninvasively diagnosing and staging NAFL remains a clinical challenge (36,37). Blood tests for liver function often give a mild phenotype in patients with NAFL, and other liver diseases, such as alcoholic liver disease and autoimmune liver disease, can manifest with similar clinical findings (37).…”

The role of conventional ultrasound in pediatric chronic liver diseases

“…In adults, the sensitivity of US for fatty liver detection seems to be around 60 to 94% and its specificity about 66 to 95% (15). In children, data analysing its accuracy are scarce.…”

“…Sensitivity and specificity are additionally decreased in very obese children (17). As many other different clinical conditions may also present with fatty liver, differentiation between them should be made only by combining clinical, biochemical, imaging and, finally, histology work ups (10,11,15).…”

Review on Liver Steatosis and its Impact on Liver Transplantation

“…14 On the basis of increasing echogenicity of the liver parenchyma compared with that of the right kidney and decreased visualization of the diaphragm and intrahepatic vessel borders, steatosis in each patient was graded as none (normal US liver structure), mild (slight increase of echogenicity, normal visualization), moderate (diffuse increase of echogenicity, slight impaired visualization), or severe (marked increase of echogenicity, poor or no visualization). 43 A review conducted by Festi et al 44 concluded that ultrasonography should be used as a first-line diagnostic tool because of its evaluation of liver steatosis and other abdominal organs. 44 Computed Tomography (CT): Fatty infiltration of the liver produces a low-density hepatic parenchyma on CT scanning.…”