Evaluation of muscle quality and quantity for the assessment of sarcopenia using mid-thigh computed tomography: a cohort study

BACKGROUND: For the diagnosis of Sarcopenia, European Working Group on Sarcopenia in Older People (EWGSOP) revised the algorisms in 2019, where they added computed tomography (CT) as an assessment tool not only for quantity but also for quality in research purpose. However, the evidence for clinical appreciation of CT has been lacking. Therefore, we investigated the correlation between CT and various motor function tests to assess the utility of CT as a potential diagnostic tool for sarcopenia. METHODS: In total, 214 patients who were examined at our center during the study period (2016–2017) were included in the study. Single-slice CT scan of the mid-thigh region was performed, from which cross-sectional area (CSA) and CT attenuation value (CTV) of quadriceps femoris were evaluated for each subject. Other assessments included skeletal muscle mass index by DXA and BIA, muscle strength and physical performance. Furthermore, subjects were classified into four groups as per the Asia Working Group of Sarcopenia (AWGS) 2019 criteria as those with: normal, poor muscle function/strength (poor function), sarcopenia and severe sarcopenia. RESULTS: Knee muscle strength correlated with CSA (r = 0.60) and the correlation was significantly greater than that with DXA and BIA. For physical performance, standing-up test correlated with CSA (r = − 0.20) and CTV (r = − 0.40) and walking speed with CTV (r = 0.43), which was significantly greater than that with DXA and BIA. The CSA was significantly lower in women with sarcopenia group and in both men and women with severe sarcopenia (all p < 0.01). Furthermore, CTV was significantly lower in women with poor-function and in both men and women with severe sarcopenia group (all p < 0.01). CONCLUSIONS: CSA mostly correlated with muscle strength, whereas CTV mostly correlated with physical performance. CT with measurements of CSA and CTV enables the evaluation of muscle mass and quality simultaneously. CT is believed to be useful in inferring evaluation of motor function and assessment of sarcopenia.