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Published on: March 21, 2021
Psoas Muscle Cross-sectional Area as a Measure of Whole-body Lean Muscle Mass in Maintenance Hemodialysis Patients
Glen R Morrell1, Talat A Ikizler2, Xiaorui Chen3
1Department of Radiology, University of Utah School of Medicine, Salt Lake City, Utah.
Objective:
We investigate whether psoas or paraspinous muscle area measured on a single L4-L5 image is a useful measure of whole lean body mass (LBM) compared to dedicated midthigh magnetic resonance imaging (MRI).
Design:
Observational study.
Setting:
Outpatient dialysis units and a research clinic.
Subjects:
One hundred five adult participants on maintenance hemodialysis. No control group was used.
Intervention:
Psoas muscle area, paraspinous muscle area, and midthigh muscle area (MTMA) were measured by magnetic resonance imaging.
Main Outcome Measure:
LBM was measured by dual-energy absorptiometry scan.
Results:
In separate multivariable linear regression models, psoas, paraspinous, and MTMA were associated with increase in LBM. In separate multivariate logistic regression models, C statistics for diagnosis of sarcopenia (defined as <25th percentile of LBM) were 0.69 for paraspinous muscle area, 0.81 for psoas muscle area, and 0.89 for MTMA. With sarcopenia defined as <10th percentile of LBM, the corresponding C statistics were 0.71, 0.92, and 0.94.
Conclusions:
We conclude that psoas muscle area provides a good measure of whole-body muscle mass, better than paraspinous muscle area but slightly inferior to midthigh measurement. Hence, in body composition studies a single axial MR image at the L4-L5 level can be used to provide information on both fat and muscle and may eliminate the need for time-consuming measurement of muscle area in the thigh.
