Reliability of Calf Bioelectrical Impedance Spectroscopy and Magnetic-Resonance-Imaging-Acquired Skeletal Muscle Hydration Measures in Healthy People

Abstract EN

Purpose.

The purpose of this study was to investigate the test-retest reliability, relative variability, and agreement between calf bioelectrical impedance-spectroscopy (cBIS) acquired extracellular fluid (ECF), intracellular fluid (ICF), total water and the ratio of ECF : ICF, magnetic-resonance-imaging (MRI) acquired transverse relaxation times (T2), and apparent diffusion coefficient (ADC) of calf muscles of the same segment in healthy individuals.

Methods.

Muscle hydration measures were collected in 32 healthy individuals on two occasions and analyzed by a single rater.

On both occasions, MRI measures were collected from tibialis anterior (TA), medial (MG), and lateral gastrocnemius (LG) and soleus muscles following the cBIS data acquired using XiTRON Hydra 4200 BIS device.

The intraclass correlation coefficients (ICC2,1), coefficient of variation (CV), and agreement between MRI and cBIS data were also calculated.

Results.

ICC2,1 values for cBIS, T2, and ADC ranged from 0.56 to 0.92, 0.96 to 0.99, and 0.05 to 0.56, respectively.

Relative variability between measures (CV) ranged from 14.6 to 25.6% for the cBIS data and 4.2 to 10.0% for the MRI-acquired data.

The ratio of ECF : ICF could significantly predict T2 of TA and soleus muscles.

Conclusion.

MRI-acquired measures of T2 had the highest test-retest reliability of muscle hydration with the least error and variation on repeated testing.

Hence, T2 of a muscle is the most reliable and stable outcome measure for evaluating individual muscle hydration.