Sarcopenia is a degenerative disease characterized by a pathological decrease in muscle strength that especially affects older people.
Researchers from the University of Barcelona (UB) have developed a new tool to assess the presence and severity of this muscular insufficiency. The study provides a muscle quality scoring system based on musculoskeletal ultrasound scans, which has been validated with anatomical and histological specimens from patients. It is the first imaging method that assesses muscle quality, an essential factor in the disease. According to the researchers, these results could be useful “not only for diagnostic purposes, but also for monitoring patients in clinical practice and in clinical trials.”
Researchers from the Human Anatomy and Embryology Unit and the Histology Unit of the Department of Pathology and Experimental Therapeutics of the Faculty of Medicine and Health Sciences (Campus Bellvitge) of the UB have participated in the work. Experts from the Puigvert Foundation, the University of Genoa, the University of Oslo and the University of Copenhagen have also participated in the study.
A harmless and low-cost technique
A key characteristic of sarcopenia is the deterioration in the quantity and quality of muscle, which worsens the quality of life and is associated with cardiorespiratory diseases and an increased risk and prolongation of hospital admission. Currently, a wide range of tests and tools are available for the characterization of the disease in practice and in research. «In most cases, the diagnosis and evolution is measured by functional tests or patient surveys on aspects such as falls, feeling weak, slowness when walking, difficulty getting up from a chair or weight loss, which allow us to know the patient’s condition”, explains Ingrid Möller, researcher at the UB and the Poal Institute of Rheumatology and first signatory of the study.
In this context, imaging techniques have a critical role in the objective evaluation of sarcopenic patients. However, most, such as dual-energy X-ray absorptiometry (DXA), magnetic resonance imaging (MRI), or computed tomography (CT), focus on muscle quantity. “These techniques show the quantity of muscle, but muscle quality —which is a relatively new term— is more important, since the quantity is highly variable due to different factors such as age or height,” the researcher points out.
Currently there is no universal consensus on the appropriate assessment methods of muscle quality in routine clinical practice. In this situation, the researchers propose the use of musculoskeletal ultrasound, as it is a technique capable of showing muscle texture and changes in microscopic and macroscopic aspects of muscle architecture and composition that cause sarcopenia. In addition, unlike other imaging techniques, it is a low-cost, portable, and harmless test that does not emit ionizing radiation.
Validated method with clinical measurements
To confirm the diagnostic validity of this new tool, the study evaluated a muscle from the lower extremity (rectus femoris) and another from the upper extremity (biceps brachii) from ten cadavers of donors between 68 and 91 years of age. To do this, two investigators qualitatively assessed and scored the severity of muscle degeneration from ultrasound images and then compared the results with the anatomical and histological evaluation of the cadavers.
The evaluation was carried out blindly with respect to the other evaluator and half an hour later, each of the investigators repeated it. In addition, evaluation by an experienced histologist under the same methodological conditions was also added. According to the researchers, this methodology is one of the “strengths of the study, as it allows direct comparison between imaging and clinical measurements of muscle quality.”
The challenge of clinical application: clinical trial with patients
The next challenge for the researchers is to verify the scoring system in patients and test the added value of the tool in the long-term follow-up of patients with sarcopenia, as well as its application in related clinical trials. In this sense, according to the researcher, the team from the University of Copenhagen that has participated in this work will apply the new tool in a cohort of patients to see how it works in prognostic value. “We believe that it works very well on diagnoses, but both in this case and in its prognostic value, it must be confirmed in longitudinal studies with patients”, explains Ingrid Möller.
From left to right, researchers from the UB Faculty of Medicine and Health Sciences (Bellvitge Campus) Maribel Miguel, Ingrid Möller and Joan Blasi. (Photo: UB)
A potential tool to apply in other diseases
Muscle quality is an important factor in other muscle diseases besides sarcopenia. In this way, for researchers, musculoskeletal ultrasound ultrasound could also have an application in other disorders or even in the rehabilitation of athletes, since it will allow a deeper understanding of muscle quality, its variations in different immunological, degenerative diseases , metabolic and treatment monitoring. “It is the starting point in a field in which there is no similar test, so we believe that it is a tool that will spread in this and other diseases,” concludes Ingrid Möller.
The study is titled “Ultrasound assessment of degenerative muscle sarcopenia: the University of Barcelona ultrasound scoring system for sarcopenia”. And it has been published in the academic journal RMD Open. (Source: UB)