Skeletal muscle cutoff values for sarcopenia diagnosis using T10 to L5 measurements in a healthy US population

Abstract

Measurements of skeletal muscle cross-sectional area, index, and radiation attenuation utilizing clinical computed tomography (CT) scans are used in assessments of sarcopenia, the loss of skeletal muscle mass and function associated with aging. To classify individuals as sarcopenic, sex-specific cutoffs for ‘low’ values are used. Conventionally, cutoffs for skeletal muscle measurements at the level of the third lumbar (L3) vertebra are used, however L3 is not included in several clinical CT protocols. Non-contrast-enhanced CT scans from healthy kidney donor candidates (age 18–40) at Michigan Medicine were utilized. Skeletal muscle area (SMA), index (SMI), and mean attenuation (SMRA) were measured at each vertebral level between the tenth thoracic (T10) and the fifth lumbar (L5) vertebra. Sex-specific means, standard deviations (s.d.), and sarcopenia cutoffs (mean-2 s.d.) at each vertebral level were computed. Associations between vertebral levels were assessed using Pearson correlations and Tukey’s difference test. Classification agreement between different vertebral level cutoffs was assessed using overall accuracy, specificity, and sensitivity. SMA, SMI, and SMRA L3 cutoffs for sarcopenia were 92.2 cm2, 34.4 cm2/m2, and 34.3 HU in females, and 144.3 cm2, 45.4 cm2/m2, and 38.5 HU in males, consistent with previously reported cutoffs. Correlations between all level pairs were statistically significant and high, ranging from 0.65 to 0.95 (SMA), 0.64 to 0.95 (SMI), and 0.63 to 0.95 (SMRA). SMA peaks at L3, supporting its use as the primary site for CT sarcopenia measurements. However, when L3 is not available alternative levels (in order of preference) are L2, L4, L5, L1, T12, T11, and T10. Healthy reference values reported here enable sarcopenia assessment and sex-specific standardization of SMA, SMI, and SMRA in clinical populations, including those whose CT protocols do not include L3.

Cancer‐Associated Malnutrition and CT‐Defined Sarcopenia and Myosteatosis Are Endemic in Overweight and Obese Patients

“…There is a need to validate other lumbar or thoracic landmarks in relation to whole body values. Recent work in this area suggests there are moderate to strong correlations between L3 and other lumbar and thoracic landmarks (eg, L2, L4, L5, L1, T12, T11, and T10), but more development is required . Ordering CT scans is under the purview of the medical oncology clinic, which limits the degree of control over if and when a CT scan is acquired.…”

“…Recent work in this area suggests there are moderate to strong correlations between L3 and other lumbar and thoracic landmarks (eg, L2, L4, L5, L1, T12, T11, and T10), but more development is required. [34][35][36] Ordering CT scans is under the purview of the medical oncology clinic, which limits the degree of control over if and when a CT scan is acquired. We included patients who had a CT on average 11 ± 39 days prior to completing a PG-SGA SF assessment.…”

Changes of computed tomography‐based body composition after adrenalectomy in patients with endogenous hypercortisolism

“…Quantifications of body composition were performed using a dedicated commercially available workstation (Aquarius 3D workstation, TeraRecon, San Mateo, CA, USA). The inferior surface of the third lumbar vertebra (L3) was selected as a landmark site for the measurement of VFA, subcutaneous fat area (SFA), and SMA based on following evidences: data from Framingham Heart Study showed that VFA and SFA obtained at L3 level were most strongly correlated with visceral and subcutaneous fat volume and cardiometabolic risk factors; SMA at L3 level showed best correlation with whole body skeletal muscle mass . CT slices were loaded onto the workstation and VFA, subcutaneous fat area (SFA), and SMA from a single CT slice of the L3 inferior surface margin were measured by applying predefined radiation attenuation cutoffs for subcutaneous fat (−190 to −30 HU), visceral fat (−150 to −50 HU), and skeletal muscle (−29 to +150 HU).…”

“…Sarcopenia (L3 SMI: male <45.4 cm 2 /m 2 ; female <34.4 cm 2 /m 2 ) and low SMD (L3 SMD: male <38.5 HU; female <34.3 HU) were defined using threshold derived from a cohort of healthy kidney donors. 18 Visceral obesity (VFA > 100 cm 2 ) was defined based on the guideline from Japan Society of the Study of Obesity. 21 Hypertension was defined as having documented hypertension diagnosis with the use of at least 1 antihypertensive drug.…”

Classifying sarcopenia: using median value or cut-off values?

“…We propose that using common pre-specified cut-off values to define sarcopenia might be more useful and better feasible than median values. Previously, European Sarcopenia consensus [1] and sarcopenia definition for American population by Derstine et al [2] determined cut-off values for sarcopenia for both European and American population. In Korean population, it was defined as 49 cm 2 m −2 for men and 31 cm 2 m −2 for women on L3 vertebra level muscle volume by KHANES study (Korean population, based on the Korea National Health and Nutrition Examination Study) [3].…”