A Systematized Review of Quantitative Ultrasound Techniques for Brain Tissue Characterization

Area of Science:

• Neuroimaging
• Biomedical Engineering
• Medical Physics

Background:

• Acoustic characterization, specifically quantitative ultrasound (QUS), has been utilized since 1968 for assessing brain tissue properties.
• While QUS provides critical microstructural insights, its translation into clinical neuroimaging practice remains limited.

Purpose of the Study:

• To synthesize advancements in quantitative ultrasound (QUS) techniques for brain tissue characterization.
• To focus on the potential and current limitations of QUS as a neuroimaging tool for the brain.

Main Methods:

• A systematized literature review was conducted, searching PubMed, Scopus, and digital libraries.
• 115 publications were identified, with 35 analyzed after applying inclusion criteria.
• Studies were categorized by QUS feature (speed of sound, attenuation, backscatter, speckle statistics) and experimental model (phantoms, preclinical, human ex vivo/in vivo).

Main Results:

• Attenuation was the most investigated QUS feature (40%), followed by speed of sound, backscatter, and speckle statistics.
• The majority of studies were performed in preclinical settings, indicating limited clinical translation.
• Methodological barriers to reproducibility include protocol variability, system-dependent processing, lack of reference standards, and calibration frameworks.

Conclusions:

• Quantitative ultrasound (QUS) holds significant potential for brain characterization but requires overcoming substantial methodological and practical barriers.
• Future research should focus on developing traceable phantoms, open data repositories, and inter-agency collaboration.
• Establishing QUS as a reliable, quantitative, and clinically meaningful neuroimaging modality necessitates coordinated efforts among researchers, clinicians, industry, and regulatory bodies.