Ultrasound-based Morphometry for the Development of Diagnostic and Prognostic Markers in Current and Chronic Diseases

Frailty is a well-known syndrome that has a negative impact on many diseases and the course of disease. Patients affected by frailty are particularly vulnerable due to their inadequate ability to deal with extrinsic and intrinsic stress factors. The prevalence of frailty increases with age, affecting 15% of people over the age of 65 and 25% of people over the age of 80.

Frailty is the end result of an interplay between malnutrition, cognitive impairment and muscle wasting. Each of these factors can be further examined and measured, but they also influence each other. In particular, reduced muscle mass and muscle function have been associated with poor quality of life and a worse course of disease. Sarcopenia is therefore becoming an increasingly important factor in various disease patterns and should be monitored further. Muscle wasting and sarcopenia have multifactorial causes. Physical inactivity, chronic inflammation associated with chronic diseases, and malnutrition are particularly noteworthy in this context. Cross-sectional measurement of several muscles at the level of the lumbar vertebrae (L3), normalized to body size, and dual-energy X-ray absorptiometry are currently the most commonly used techniques for measuring sarcopenia. However, the measurements require complex equipment and procedures. In addition, radiological imaging is costly and causes radiation exposure. Therefore, attempts have been made in the past to simplify the measurements. Sonographic measurement is a practical alternative. Many different muscle groups are accessible to ultrasound. In particular, the thigh muscles and the psoas major muscle can be easily visualized sonographically. The sonographic assessment of the psoas muscle area index (PMAI) and the thigh muscle thickness index (TMTI) are approaches for bedside morphometry that the investigators use primarily.

Sarcopenia needs to be further investigated and included in the evaluation of therapeutic concepts. Recently, Zhang et al. showed that radiologically measured reduced psoas muscle mass was associated with poorer overall survival in HCC patients. Furthermore, it has been suggested several times that sarcopenia should be integrated into the MELD classification for liver transplantation. The investigators were also recently able to show in a cohort of COVID-19 patients that reduced muscle mass was associated with a poorer disease course during the pandemic.

The investigators expect sonographic measurements of the musculature to provide a better assessment of prognosis, quality of life and functional results under therapy.