Ultrasound: a routine examination with limitations for steatosis quantification
Ultrasound is often the first examination performed when liver steatosis is suspected. It allows visualization 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, standardized, 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 standardized 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 standardization, 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.
The FibroScan device (Models: 502 Touch, 530 Compact, 430 Mini+, 230, and 630) is intended to measure liver stiffness (E) using Vibration Controlled Transient Elastography (VCTE) at 50 Hz shear wave frequency and liver ultrasound attenuation coefficient (CAP)* at 3.5 MHz. FibroScan 630 Expert is also intended to measure spleen stiffness using VCTE at 100 Hz shear wave frequency. FibroScan liver stiffness measurements (LSM) by VCTE may aid the physician in determining the likelihood of cirrhosis and may be used, taken in context with other clinical and laboratory data, as an aid in the assessment of liver fibrosis. FibroScan CAP measurements may be used, taken in context with other clinical and laboratory data, as an aid in the assessment of hepatic steatosis. FibroScan is indicated as a non-invasive aid for the clinical management, diagnosis, and monitoring of adult and pediatric patients with confirmed or suspected liver disease, as part of an overall assessment of the liver. Results in the pediatric population should be interpreted while considering the clinical condition and the overall patient profile. The FibroScan device is intended for use by healthcare professionals in hospitals, clinics or any facility where healthcare is provided. *CAP refers to ultrasound attenuation coefficient (originally defined as Controlled Attenuation Parameter). CAP on S+ probe is only available with SmartExam capability.
