Frequency-dependent ultrasonic differentiation of normal and diffusely diseased liver

Area of Science:

• Medical Imaging
• Biophysics
• Pathology

Background:

• Liver disease diagnosis relies on accurate tissue characterization.
• Ultrasound attenuation coefficient is a potential biomarker for liver disease severity.
• In vitro studies are crucial for understanding fundamental biophysical properties.

Purpose of the Study:

• To quantify ultrasound attenuation in pathologically graded liver specimens.
• To investigate the frequency dependence of attenuation in normal and diseased liver tissue.
• To determine the optimal frequency range for differentiating liver disease severity using ultrasound.

Main Methods:

• Measurement of ultrasound attenuation coefficient in 38 in vitro liver specimens across a 1.25-8 MHz frequency range.
• Fitting attenuation data to a power law model (Af^B) for each pathological group.
• Statistical analysis (Student's t test) of attenuation slopes to assess group differences.

Main Results:

• Attenuation exhibited power law frequency dependence in all groups: normal (0.399f^1.139), mild (0.395f^1.212), and moderate/severe (0.391f^1.325).
• Frequency dependence significantly impacted statistical differentiation of disease groups between 1-4 MHz.
• The normal vs. moderate/severe disease group showed the most significant difference, particularly below 4 MHz.
• Attenuation slope values at 3 MHz correlated with in vivo findings.

Conclusions:

• Ultrasound attenuation's frequency dependence varies with liver disease severity in vitro.
• The 1-4 MHz frequency range is most effective for differentiating liver disease stages based on attenuation slope.
• These findings support the potential of ultrasound attenuation as a non-invasive biomarker for liver disease.