Metabolism-Oriented Ultrasound in MetS at the Initial Stages of the Cardio-Reno-Metabolic Continuum

Background. Metabolic syndrome (MetS) is a systemic metabolic disorder characterized by insulin resistance, visceral obesity, dyslipidemia, hypertension, and progressive multi-organ involvement. Metabolic dysfunction-associated steatotic liver disease (MASLD) represents one of the major hepatic manifestations of this process. Recent advances in quantitative ultrasound (US) have expanded the possibilities for non-invasive assessment of hepatic steatosis; however, US findings are still commonly interpreted using an organ-centered approach.Aim. To evaluate the relationships between anthropometric, metabolic, and hepatic US domains, determine their independent associations with liver fat content measured by magnetic resonance imaging proton density fat fraction (MRI-PDFF), and substantiate the concept of metabolic-oriented US (MetUS) for the comprehensive assessment of patients with MetS.Materials and methods. This prospective single-center observational study included 104 adults with suspected MASLD. All participants underwent anthropometric assessment, bioelectrical impedance analysis, laboratory evaluation including liver enzymes and HOMA-IR, and multiparametric liver ultrasound including attenuation coefficient measurement (ACM), hepatorenal index, two-dimensional shear-wave elastography (2D-SWE), and liver morphometry. MRI-PDFF, used as the reference method for quantitative liver fat assessment, was available in 91 patients. Spearman correlation analysis and multivariable linear regression with HC3 robust standard errors were performed.Results. Increasing steatosis severity was accompanied by progressive deterioration of anthropometric, metabolic, and hepatic US characteristics. Significant inter-domain correlations were observed, with the strongest relationships identified between waist circumference and left hepatic lobe thickness (ρ=0.693), visceral fat level and left hepatic lobe thickness (ρ=0.616), and ACM and HOMA-IR (ρ=0.351). In multivariable analysis, ACM demonstrated the strongest independent association with MRI-PDFF, whereas body mass index, HOMA-IR, and alanine aminotransferase activity also remained independent predictors of hepatic fat content. In contrast, liver stiffness measured by 2D-SWE showed no significant associations with most anthropometric or metabolic variables.Conclusions. 1. The existence of close relationships between anthropometric, cardiometabolic and hepatic US characteristics of patients with MASLD reflects the central metabolic role of the liver in the development of manifestations of a general pathological process of MetS and justifies the feasibility of using MetUS in a multi-domain approach to the comprehensive assessment of patients with MetS at the initial stages of the cardio-reno-metabolic continuum.The innovative ultrasound technology of liver steatometry using ACM demonstrated the strongest independent association with liver fat content according to MRI-PDFF data, confirming its leading role in the non-invasive assessment of hepatic steatosis as a key element of systemic metabolic disorders.The MetUS concept provides a structured interpretation of quantitative ultrasound findings in the context of systemic metabolic disorders and can contribute to risk stratification, individualization of diagnostic pathways, and clinical decision-making regarding patients with MetS at the initial stages of the cardio-reno-metabolic continuum.