Attenuation Estimation and Acoustic Characterization of Mouse Lymph Node Tumor Using High-frequency Ultrasound

Area of Science:

• Biomedical Ultrasound
• Cancer Diagnostics
• Acoustic Imaging

Background:

• Lymph node biopsy is standard for metastasis diagnosis.
• Ultrasound offers real-time, non-invasive assessment but is operator-dependent.
• Quantitative ultrasound (QUS) provides operator-independent parameters by characterizing tissue microstructure.

Purpose of the Study:

• Investigate the link between tumor growth and ultrasound attenuation coefficient (AC).
• Explore changes in acoustic impedance and speed of sound during tumor progression.
• Assess the role of AC in quantitative ultrasound for metastasis detection.

Main Methods:

• In vivo high-frequency ultrasound (25 MHz) and ex vivo scanning acoustic microscopy (80 and 300 MHz) were used.
• FM3 A-Luc mammary carcinoma cells were inoculated into mouse lymph nodes.
• Tumor growth was monitored using bioluminescence imaging and ultrasound measurements.

Main Results:

• The mean AC decreased, and its standard deviation increased with tumor growth, correlating with bioluminescence.
• Acoustic impedance and speed of sound differed between normal and tumor tissues.
• Histopathological analysis confirmed microstructural differences.

Conclusions:

• Decreased AC with tumor growth is a key finding for QUS.
• This observation can enhance attenuation compensation accuracy in QUS.
• Improved QUS accuracy may lead to better differentiation of metastatic and non-metastatic lymph nodes.