From the Guidelines
The best test for diagnosing fatty liver disease is conventional ultrasound, as it is recommended as a first-line tool for the diagnosis of steatosis in clinical practice, despite its well-known limitations 1. This recommendation is based on the European Association for the Study of the Liver (EASL) clinical practice guidelines, which state that conventional ultrasound is the preferred initial method for detecting steatosis due to its widespread availability and non-invasive nature 1.
Key Points to Consider:
- Conventional ultrasound is recommended as the first-line tool for diagnosing steatosis, with a strong recommendation and 100% Delphi Panel agreement 1.
- MRI-PDFF is the most accurate non-invasive method for detecting and quantifying steatosis but is not recommended as a first-line tool due to its cost and limited availability 1.
- Non-invasive scores are not recommended for the diagnosis of steatosis in clinical practice, with a strong recommendation and 84% Delphi Panel agreement 1.
- CAP is a promising point-of-care technique for detecting steatosis but lacks head-to-head studies compared to ultrasound and is not yet recommended as a first-line technique 1.
Additional Testing:
For patients who require more detailed assessment, transient elastography (TE) can be used to evaluate liver stiffness and detect advanced fibrosis 1.
- TE is recommended to rule-out advanced fibrosis in patients with non-alcoholic fatty liver disease (NAFLD), with a cut-off of <8 kPa 1.
- TE can also be used to rule-in advanced fibrosis, with a cut-off of >12-15 kPa 1.
Definitive Diagnosis:
Liver biopsy remains the reference standard for diagnosing non-alcoholic steatohepatitis (NASH) and evaluating liver fibrosis improvement 1.
- However, liver biopsy is typically reserved for cases where the diagnosis is unclear or to distinguish between simple fatty liver and more advanced NASH 1.
From the Research
Diagnostic Tests for Fatty Liver
- Transient elastography (TE) is a non-invasive test that measures liver stiffness and can be used to diagnose liver fibrosis and steatosis in patients with non-alcoholic fatty liver disease (NAFLD) 2, 3, 4.
- TE has been shown to have good diagnostic accuracy compared to liver biopsy, with sensitivity and specificity ranging from 82.4% to 96.2% and 91.1% to 92.2%, respectively 2.
- The use of TE can help exclude liver cirrhosis and has an important role in the management of NAFLD patients 2, 3.
- Other non-invasive tests, such as FibroTest and acoustic force radiation impulse (ARFI), have also been evaluated, but TE has been shown to be a reliable and accurate test for liver fibrosis and steatosis 4.
Comparison with Liver Biopsy
- Liver biopsy is considered the gold standard for diagnosing liver fibrosis and steatosis, but it is an invasive procedure with potential complications and sampling errors 5, 6.
- Non-invasive tests, such as TE, offer a safer and more convenient alternative to liver biopsy for diagnosing liver fibrosis and steatosis 3, 4.
- TE can be used to monitor disease progression and response to treatment, and can help identify patients with advanced fibrosis or non-alcoholic steatohepatitis 3, 4.
Limitations and Future Directions
- TE may not be suitable for all patients, particularly those with obesity, as it can be difficult to obtain accurate measurements 3.
- The use of a new XL probe with a larger probe and lower ultrasound frequency can improve the success rate of TE in obese patients 3.
- Further studies are needed to confirm the results of TE and to evaluate its clinical utility in different patient populations 2, 4.