Ultrasound: a routine examination with limitations for steatosis quantification
Ultrasound is often the first examination performed when liver steatosis is suspected. It allows visualisation of liver hyperechogenicity, an indirect sign of intrahepatic fat accumulation.
Strengths :
– Accessible and available in most healthcare settings
– Enables assessment of liver morphology
– Useful for detecting other abdominal abnormalities
Limits :
– Operator-dependent examination⁴
– Reduced sensitivity for detecting early-stage steatosis
– Lower diagnostic performance in patients with obesity⁵
– Does not provide quantitative assessment
In a context where MASLD is highly prevalent among patients with diabetes and obesity, these limitations reduce the ability of ultrasound to detect liver steatosis at an early stage.
CAP: a quantitative, standardised, and reproducible measurement
CAP (Controlled Attenuation Parameter) measures ultrasound attenuation in the liver, expressed in dB/m. Unlike ultrasound, CAP provides an objective, operator-independent quantification of steatosis.³
The clinical advantages of CAP
– Quantitative and dynamic parameter, suitable for patient monitoring⁶
– Reproducible² and standardised examination
– More than 2,125 publications supporting its use⁷
– Applicable across all patient body types, including patients with obesity (VCTE® XL probe)⁸
– Direct integration into the same examination as liver elasticity measurement (LSM by VCTE®)
A tool adapted for screening at-risk populations
CAP integrates seamlessly into care pathways based on non-invasive tests recommended by scientific societies, particularly in combination with liver stiffness measurement (LSM by VCTE®) and the FAST and Agile scores.
In summary
Abdominal ultrasound and CAP do not address the same objectives. Ultrasound remains an essential examination, but CAP is the most appropriate method for quantifying steatosis at an early stage⁵, particularly in MASLD/MASH care pathways and in patients at high metabolic risk.
Thanks to its standardisation, reproducibility, and integration into FibroScan®, CAP enables earlier detection of steatosis, improved risk stratification, and effective longitudinal patient monitoring.⁶˒⁹
1- Whitepaper Vibration-Controlled Transient Elastography Explained
2- Recio, Eva et al. “Interobserver concordance in controlled attenuation parameter measurement, a novel tool for the assessment of hepatic steatosis on the basis of transient elastography.” European journal of gastroenterology & hepatology vol. 25,8 (2013): 905-11.
3- Petroff, David et al. “Assessment of hepatic steatosis by controlled attenuation parameter using the M and XL probes: an individual patient data meta-analysis.” The lancet. Gastroenterology & hepatology vol. 6,3 (2021): 185-198.
4- Strauss, Simon et al. “Interobserver and intraobserver variability in the sonographic assessment of fatty liver.” AJR. American journal of roentgenology vol. 189,6 (2007): W320-3. doi:10.2214/AJR.07.2123
5 – Ferraioli, Giovanna, and Livia Beatriz Soares Monteiro. “Ultrasound-based techniques for the diagnosis of liver steatosis.” World journal of gastroenterology vol. 25,40 (2019): 6053-6062.
6 – Armandi, Angelo et al. “Short-term reduction of dietary gluten improves metabolic-dysfunction associated steatotic liver disease: A randomised, controlled proof-of-concept study.” Alimentary pharmacology & therapeutics vol. 59,10 (2024): 1212-1222.
7 – www.pubmed/com, as per July 2026
8 – Sasso, Magali et al. “Liver Steatosis Assessed by Controlled Attenuation Parameter (CAP) Measured with the XL Probe of the FibroScan: A Pilot Study Assessing Diagnostic Accuracy.” Ultrasound in medicine & biology vol. 42,1 (2016): 92-103.
9- Oh, Sechang et al. “Weight-loss-independent benefits of exercise on liver steatosis and stiffness in Japanese men with NAFLD.” JHEP reports : innovation in hepatology vol. 3,3 100253. 10 Feb. 2021.
Products in the FibroScan range are class IIa medical devices according to Rule 10 of ANNEX VIII of Regulation EU 2017/745 (CE 0459) and are manufactured by Echosens. FibroScan devices are intended to provide: Liver stiffness measurements at a shear wave frequency of 50 Hz, liver ultrasound attenuation measurements (CAP: Controlled Attenuation Parameter) at 3.5 MHz and spleen stiffness measurements at a shear wave frequency of 100 Hz (FibroScan 630 Expert only). These non-invasive devices are intended to aid clinical management, diagnosis, and monitoring of patients with confirmed or suspected chronic liver disease, as part of an overall assessment of the liver. FibroScan devices may aid the healthcare professionals in the assessment of liver fibrosis, steatosis, and in determining the likelihood of cirrhosis, and its complications (FibroScan 630 Expert only). They are used, in conjunction with other clinical and laboratory data, during liver assessment in patients with confirmed or suspected chronic liver disease. Examinations with FibroScan devices shall be performed by an operator who has been certified by the manufacturer or its approved local representative. Operators are expressly recommended to carefully read the instructions given in the user manual and on the labelling of these products. Check cost defrayal conditions with paying bodies. Fast is a class IIa medical device according to Rule 11 of Annex VIII of Regulation EU 2017/745 (CE 0459) and is manufactured by Echosens. Fast is an algorithm intended to aid in the diagnosis of active fibrotic Non-Alcoholic Steatohepatitis (NASH) in patients with suspected Non-Alcoholic Fatty Liver Disease (NAFLD). Fast is used, during liver assessment, in patient with suspected NAFLD. Fast is presented as an educational service intended for licensed healthcare professionals. While this score is about specific medical and healthcare issues, it is not a substitute for or replacement of personalized medical advice and is not intended to be used as the sole basis for making individualized medical or health-related decisions. The following precautions must be observed when using Fast: LSM (also known as E) and CAP measurements must come from the same FibroScan examination; There must be no more than 6 months between the FibroScan examination and the blood sample necessary for AST assessment. Fast must not be used in the following situations : pregnancy, patients under 18 years old, chronic or acute liver diseases other than NAFLD, liver transplant patients, cardiac failure and/or significant vascular disease, confirmed diagnosis of active malignancy or other terminal disease, use of treatment inducing liver injury. Users are expressly recommended to carefully read the instructions given in the user manual. User manual is available on the Score interface or Echosens website. To access, please make sure to be connected to the internet.
