Reference values of skeletal muscle area for diagnosis of sarcopenia using chest computed tomography in Asian general population

Abstract

Background Diagnostic cutoff points for sarcopenia in chest computed tomography (CT) have not been established although CT is widely used for investigating skeletal muscles. This study aimed to determine reference values for sarcopenia of thoracic skeletal muscles acquired from chest CT scans and to analyse variables related to sarcopenia using the cutoff values determined in a general Asian population. Methods We retrospectively reviewed chest CT scans of 4470 participants (mean age 54.8 ± 9.9 years, 65.8% male) performed at a check‐up centre in South Korea (January 2016–August 2017). To determine cutoffs, 335 participants aged 19–39 years (mean age 35.2 ± 3.6 years, 75.2% male) were selected as the healthy and younger reference group, and 4135 participants aged ≥40 years (mean age 56.4 ± 8.4 years, 65.1% male) were selected as the study group. We measured the following: cross‐sectional area (CSA) of the pectoralis, intercostalis, paraspinal, serratus, and latissimus muscles at the 4th vertebral region (T4CSA); T4CSA divided by height2 (T4MI); pectoralis muscle area (PMCSA); and PMCSA divided by height2 (PMI) at the 4th vertebral region. Sarcopenia cutoff was defined as sex‐specific values of less than −2 SD below the mean from the reference group. Results In the reference group, T4CSA, T4MI, PMCSA, and PMI cutoffs for sarcopenia were 100.06cm2, 33.69cm2/m2, 29.00cm2, and 10.17cm2/m2 in male, and 66.93cm2, 26.01cm2/m2, 18.29cm2, and 7.31cm2/m2 in female, respectively. The prevalence of sarcopenia in the study group measured with T4CSA, T4MI, PMCSA and PMI cutoffs were 11.4%, 8.7%, 8.5%, and 10.1%, respectively. Correlations were observed between appendicular skeletal mass divided by height2 measured by bioelectrical impedance analysis (BIA) and T4CSA (r = 0.82; P < 0.001)/T4MI (r = 0.68; P < 0.001), and ASM/height2 measured by BIA and PMCSA (r = 0.72; P < 0.001)/PMI (r = 0.63; P < 0.001). In the multivariate logistic regression models, sarcopenia defined by T4CSA/T4MI were related to age [odds ratio (95% confidence interval), P‐values: 1.09 (1.07–1.11), <0.001/1.05 (1.04–1.07), <0.001] and diabetes [1.60 (1.14–2.25), 0.007/1.47 (1.01–2.14), 0.043]. Sarcopenia defined by PMCSA/PMI were related to age [1.09 (1.08–1.10), <0.001/1.05 (1.03–1.06), <0.001], male sex [0.23 (0.18–0.30), <0.001/0.47 (0.32–0.71), <0.001], diabetes [2.30 (1.73–3.05), <0.001/1.63 (1.15–2.32), 0.007], history of cancer [2.51 (1.78–3.55), <0.001/1.61 (1.04–2.48), 0.033], and sufficient physical activity [0.67 (0.50–0.89), 0.007/0.74 (0.56–0.99), 0.042]. Conclusions The reference cutoff values of a general population reported here will enable sex‐specific standardization of thoracic muscle mass quantification and sarcopenia assessment.

Preoperative Pectoralis Muscle Index Predicts Distant Metastasis-Free Survival in Breast Cancer Patients

“…Recent studies have observed that pectoralis muscle area (PMA), measured from CT scans of the chest, is associated with prognosis in lung cancer (17) and diffuse large B-cell lymphoma (18). Currently, the measurable indicators of muscle mass at the T4 level include skeletal muscle area (SMA) and PMA (19), but SMA in the upper thorax varies depending on upper limb positions (i.e., arms above the head versus arms by the side) (20). Therefore, PMA on chest CT imaging was used to assess the muscle area in our study.…”

Thoracic skeletal muscle mass predicts mortality in patients with surgery for pleural empyema: A case control study

“…The procedure has been described and validated before. 13 , 17 , 18 All chest CT scans were performed in a standardized position with the patient's arms positioned at the sides of the trunk following institutional protocols. All image analyses were performed by a radiologist specialized in thoracic imaging (L.M.).…”

“…The cross‐sectional slides showing the middle of the fourth thoracic vertebra were selected by the investigator based on previous suggestions. 18 Quantitative T4CSA assessment was then carried out semi‐automatically using a 3D slicer (version 5.2.2, Kitware Inc.) as shown in Figure 1 . 19 First, CSA was computed automatically by summation of the pixel attenuation of −30 to +150 Hounsfield units for skeletal muscle.…”

“… 19 First, CSA was computed automatically by summation of the pixel attenuation of −30 to +150 Hounsfield units for skeletal muscle. 18 Second, after applying the threshold method with a predefined Hounsfield unit threshold to slices, boundaries between different tissues were manually corrected. After determination of T4CSA for each patient, TSMI was calculated as T4CSA (in square centimeters) divided by body height in meters squared (in square centimeters per square meter).…”

Sex- and region-specific associations of skeletal muscle mass with metabolic dysfunction-associated fatty liver disease

“…A large cohort of UK adults has revealed that greater muscle quality was associated with decreased risk of cardiovascular mortality (5). In addition, muscle weakness has been observed to be associated with T2DM, which was an important component of MAFLD (6). As an endocrine organ, skeletal muscle can secrete myokines that might affect the function of the liver (7).…”