Sarcopenia, a progressive age-related loss of skeletal muscle mass, strength, and function, is a major contributor to disability, reduced quality of life, and mortality in older adults. While current diagnostic approaches, such as dual-energy X-ray absorptiometry (DXA), bioelectrical impedance analysis (BIA), magnetic resonance imaging (MRI), and computed tomography (CT), are widely used to assess muscle mass, they have limitations in detecting early qualitative changes in muscle architecture and composition. Shear Wave Elastography (SWE), an ultrasound-based technique that quantifies tissue stiffness, has emerged as a promising tool to evaluate both muscle quantity and quality in a non-invasive, portable, and reproducible manner. Studies suggest that SWE can detect alterations in muscle mechanical properties associated with sarcopenia, providing complementary information to traditional morphometric assessments. Preliminary evidence indicates its good reproducibility, feasibility in various clinical settings, and potential for integration into routine evaluations. This narrative review summarizes current evidence on the use of SWE for the assessment of sarcopenia across diverse populations.

Background/Objectives: The attenuation coefficient (AC) is a quantitative ultrasound parameter that describes the frequency-dependent reduction of acoustic energy as ultrasound waves propagate through biological tissues. Recently, AC has gained increasing relevance in abdominal ultrasound as an objective and reproducible biomarker for tissue characterization, particularly in the assessment of diffuse parenchymal diseases. Unlike conventional qualitative B-mode imaging, AC provides standardized numerical measurements that improve interobserver reproducibility and facilitate longitudinal monitoring. Methods: This review provides a comprehensive and critical overview of the current clinical applications of AC measurements in abdominal ultrasound, mainly focusing on liver steatosis quantification. Emphasis is placed on the comparative evaluation of commercially available AC-based technologies, highlighting their methodological differences, validation evidence, and diagnostic performance to support future efforts toward harmonization and standardization across ultrasound platforms. Results: Several studies have demonstrated a strong correlation between AC values and established reference standards, including magnetic resonance imaging–proton density fat fraction (MRI-PDFF) and histopathological grading, supporting its role in the noninvasive evaluation of liver steatosis. The growing clinical adoption of AC has been accompanied by the development of multiple vendor-specific software implementations integrated into modern ultrasound systems. Although these platforms share a common physical basis, they differ substantially in algorithmic design, signal processing strategies and region-of-interest selection. These differences may influence absolute AC values and diagnostic cutoff thresholds, therefore limiting direct comparability across systems. Another factor that further contributes to the heterogeneity of reported cutoff values is the variability in validation approaches, with some technologies validated against liver biopsy and others against MRI-PDFF. Conclusions: AC is a promising quantitative ultrasound biomarker for noninvasive liver steatosis assessment, showing strong correlation with histology and MRI-PDFF. However, inter-vendor variability currently limits cross-platform comparability. Standardized acquisition protocols, unified quality-control criteria, phantom-based cross-calibration, and consistent vendor-specific reporting are essential to ensure reliable longitudinal monitoring and broader clinical implementation.

Background: Rheumatoid arthritis (RA) is a chronic inflammatory joint disease that significantly impacts quality of life, particularly among women. Previous studies have suggested that oral contraceptive (OC) use may influence RA risk, but conflicting findings from earlier meta-analyses necessitate an updated analysis incorporating more recent data. Methods: We conducted a systematic review and meta-analysis of observational studies on OC use and RA risk by searching MedLine (via PubMed), Scopus, and Cochrane Databases up to September 2024. Results: Our analysis demonstrated that current or prior use of OCs is associated with a statistically significant reduction in RA risk (OR 0.80, 95% CI 0.70–0.91). In contrast, the associations for current use (OR 0.59, 95% CI 0.34–1.02) and past use (OR 0.83, 95% CI 0.69–1.01) were less definitive, likely due to substantial heterogeneity among studies. Cumulative meta-analysis revealed a modest temporal trend toward a protective effect of OC use. Conclusions: This meta-analysis supports a protective association between current or prior OC use and the development of RA, highlighting the potential role of hormonal factors in RA pathogenesis.