Myosteatosis as a Shared Biomarker for Sarcopenia and Cachexia Using MRI and Ultrasound

Area of Science:

• Biomedical Engineering
• Radiology
• Gerontology

Background:

• Myosteatosis, or fat infiltration in muscle, is a key component of sarcopenia and cachexia.
• Current diagnostic methods for myosteatosis lack bedside applicability and may be less sensitive than advanced imaging.
• Establishing reliable bedside biomarkers is crucial for timely diagnosis and management of muscle-wasting conditions.

Purpose of the Study:

• To establish bedside ultrasound biomarkers for myosteatosis.
• To compare ultrasound-based myosteatosis measures with MRI and CT imaging in healthy and lung cancer patients.
• To evaluate the diagnostic utility of ultrasound biomarkers against traditional measures like BMI.

Main Methods:

• A cross-sectional pilot study compared ultrasound (echo intensity, shear wave speed) and MRI (proton density fat-fraction) measures of myosteatosis.
• Participants included young healthy adults, older healthy adults, and older adults undergoing lung cancer treatment.
• Muscle biopsies and CT scans were analyzed for correlation with imaging and ultrasound findings.

Main Results:

• MRI-based fat fraction (PDFF) was significantly lower in young adults compared to older adults.
• Ultrasound echo intensity (EI) was lower in young adults than older healthy adults.
• PDFF strongly correlated with EI, suggesting ultrasound's potential to reflect intramuscular fat content.

Conclusions:

• Ultrasound measures, particularly echo intensity, show strong association with MRI-derived fat fraction, indicating potential as bedside biomarkers for myosteatosis.
• Ultrasound biomarkers may offer greater diagnostic utility for sarcopenia and cachexia compared to BMI.
• These findings support the development of ultrasound techniques for non-invasive assessment of myosteatosis at the bedside.