From the Guidelines
Liver elastography is not routinely recommended for managing mild fatty liver disease, as its primary use is to assess liver stiffness as a marker of fibrosis, which is more relevant in advanced stages of the disease. In mild cases without suspected fibrosis, lifestyle modifications remain the cornerstone of management, including weight loss of 7-10% of body weight, regular exercise (150 minutes of moderate activity weekly), and dietary changes (reducing processed foods, simple carbohydrates, and saturated fats) 1. These interventions address the underlying cause of fat accumulation in the liver. Elastography becomes more valuable when there is concern for disease progression to non-alcoholic steatohepatitis (NASH) or fibrosis, particularly in patients with risk factors such as diabetes, obesity, or elevated liver enzymes.
Some key points to consider when using liver elastography include:
- Transient elastography (TE) has a sensitivity and specificity of 70% and 84%, respectively, for diagnosing significant fibrosis (F2) and 87% and 91%, respectively, for diagnosing cirrhosis (F4) 1.
- TE is not reliable in patients with obesity or ascites and cannot distinguish between intermediate stages of fibrosis 1.
- Magnetic resonance elastography (MRE) shows high diagnostic accuracy for liver fibrosis and has the advantage of evaluating the entire liver parenchyma, with no limitations for obese patients 1.
- MRE is the most accurate non-invasive test for liver fibrosis, with a diagnostic performance superior to that of transient elastography 1.
In cases where elastography is deemed necessary, techniques like transient elastography (FibroScan), magnetic resonance elastography, or acoustic radiation force impulse imaging can help determine if fibrosis is developing, which would warrant more aggressive management and closer monitoring 1. For mild fatty liver disease without risk factors, regular monitoring of liver enzymes and metabolic parameters is generally sufficient.
From the Research
Liver Elastography for Mild Fatty Liver
- Liver elastography is a non-invasive method used to assess liver fibrosis in patients with mild fatty liver disease 2, 3, 4, 5, 6.
- The technique measures liver stiffness, which is a surrogate marker for fibrosis burden in chronic liver disease (CLD) 5.
- Different methods of liver elastography are available, including point-shear wave elastography (ElastPQ), transient elastography (FibroScan), vibration-controlled transient elastography (VCTE), and magnetic resonance elastography (MRE) 2, 3, 5.
- These methods have been shown to have excellent correlation with each other and with liver histology in diagnosing liver fibrosis 2, 3.
- The diagnostic accuracy of liver elastography for mild fatty liver disease is acceptable, with area under the curve (AUC) values ranging from 0.83 to 0.95 for different stages of fibrosis 2, 3.
Clinical Applications of Liver Elastography
- Liver elastography can be used to diagnose and stage liver fibrosis, predict liver decompensation, and differentiate non-alcoholic steatohepatitis (NASH) from simple steatosis (SS) 3, 5.
- The technique is also useful in monitoring disease progression and response to treatment in patients with mild fatty liver disease 4.
- However, the clinical impact of liver elastography is limited by the lack of intention-to-diagnose analyses and validation of pre-specified thresholds 3.
Interpretation of Liver Elastography Results
- The results of liver elastography are interpreted based on the liver stiffness measurement (LSM), which is expressed in kilopascals (kPa) 2, 6.
- The optimal cut-off values for diagnosing different stages of fibrosis vary depending on the method used and the population being studied 2, 3.
- A larger waist circumference and higher LSM values are associated with a greater discrepancy between different elastography methods 2.