Quantitative estimation of liver attenuation and echogenicity: normal state versus diffuse liver disease

Area of Science:

• Medical Imaging
• Ultrasound Physics
• Hepatology

Background:

• Accurate estimation of tissue attenuation and echogenicity is crucial for ultrasound diagnosis.
• Previous methods like spectral-difference have limitations in accuracy and variability.
• Understanding liver tissue properties can aid in diagnosing various liver diseases.

Purpose of the Study:

• To describe and validate a novel broad-band amplitude-based method for ultrasound attenuation and echogenicity estimation.
• To apply this method to assess liver tissue properties in healthy volunteers and patients with liver disease.
• To investigate the diagnostic utility of these parameters in conditions like chronic hepatitis, Gaucher disease, and fatty liver.

Main Methods:

• A new method utilizing broad-band amplitude was developed for attenuation and echogenicity estimation.
• The method was validated using homogeneous phantoms and biological tissues.
• The technique was applied to the livers of 18 healthy volunteers and 76 patients with liver disease.

Main Results:

• The broad-band amplitude method demonstrated accuracy comparable to the spectral-difference method with reduced variability.
• Patients with chronic hepatitis showed a bimodal distribution of attenuation and echogenicity values.
• Fatty infiltration (including glycogen storage disease) resulted in highly attenuating and echogenic livers, confirming prior observations.
• Contrary to previous reports, patients with cirrhosis exhibited normal attenuation and echogenicity values.

Conclusions:

• The broad-band amplitude method provides a reliable and less variable approach for ultrasound tissue property estimation.
• This method highlights distinct ultrasound signatures for different liver pathologies, particularly fatty liver disease.
• The discrepancy in cirrhosis findings warrants further investigation into methodological differences and their clinical implications.