Lean regional muscle volume estimates using explanatory bioelectrical models in healthy subjects and patients with muscle wasting

Abstract

Background The availability of non‐invasive, accessible, and reliable methods for estimating regional skeletal muscle volume is paramount in conditions involving primary and/or secondary muscle wasting. This work aimed at (i) optimizing serial bioelectrical impedance analysis (SBIA) by computing a conductivity constant based on quantitative magnetic resonance imaging (MRI) data and (ii) investigating the potential of SBIA for estimating lean regional thigh muscle volume in patients with severe muscle disorders. Methods Twenty healthy participants with variable body mass index and 20 patients with idiopathic inflammatory myopathies underwent quantitative MRI. Anatomical images and fat fraction maps were acquired in thighs. After manual muscle segmentation, lean thigh muscle volume (lVMRI) was computed. Subsequently, multifrequency (50 to 350 kHz) serial resistance profiles were acquired between current skin electrodes (i.e. ankle and hand) and voltage electrodes placed on the anterior thigh. In vivo values of the muscle electrical conductivity constant were computed using data from SBIA and MRI gathered in the right thigh of 10 healthy participants. Lean muscle volume (lVBIA) was derived from SBIA measurements using this newly computed constant. Between‐day reproducibility of lVBIA was studied in six healthy participants. Results Electrical conductivity constant values ranged from 0.82 S/m at 50 kHz to 1.16 S/m at 350 kHz. The absolute percentage difference between lVBIA and lVMRI was greater at frequencies >270 kHz (P < 0.0001). The standard error of measurement and the intra‐class correlation coefficient for lVBIA computed from measurements performed at 155 kHz (i.e. frequency with minimal difference) against lVMRI were 6.1% and 0.95 in healthy participants and 9.4% and 0.93 in patients, respectively. Between‐day reproducibility of lVBIA was as follows: standard error of measurement = 4.6% (95% confidence interval [3.2, 7.8] %), intra‐class correlation coefficient = 0.98 (95% confidence interval [0.95, 0.99]). Conclusions These findings demonstrate a strong agreement of lean muscle volume estimated using SBIA against quantitative MRI in humans, including in patients with severe muscle wasting and fatty degeneration. SBIA shows promises for non‐invasive, fast, and accessible estimation and follow‐up of lean regional skeletal muscle volume for transversal and longitudinal studies.

Differential impact of osteoporosis, sarcopenia and obesity on physical performance in aging men

“…This aging process is associated with a redistribution of body fat, most notably a reduction of appendicular, mostly s.c. fat and an increase in trunk/mainly abdominal fat and also an accumulation of fat tissue within organs, including muscles and these mechanisms may have contributed to our findings of a proportionally lower loss of muscle mass as compared to the decline in fat mass (37). In that regard, it is one of the shortcomings of our study and constitutional assessments in daily practice that routine BIA as included here may not appropriately reflect this redistribution and with fatty infiltration of muscles and indeed, only very recently a technical algorithm with serial BIA and a multifrequency bioimpedance device was proposed to make up for this deficit (38). In addition, data presented we don't have longitudinal data of exactly the same individuals to reflect individual changes of body composition and work out to what extend the changes observed may be biased by technical limitation or altered group composition in the very old.…”

MRI and muscle imaging for idiopathic inflammatory myopathies

“…However, traditional bioelectrical impedance analysis may be useful for assessing and monitoring overall muscle mass and adiposity in IIM. Recently in IBM, a bioelectrical impedance analysis method based on serial bioelectrical measurements was shown to provide accurate estimates of lean thigh muscle volume versus quantitative MRI (167). This method may be useful to monitor the effects of treatment on lean muscle volume although further studies are needed to investigate its sensitivity to changes in muscle disease activity.…”

Sarcopenia: Technological Advances in Measurement and Rehabilitation

“…The results are very promising, but software accuracy should be implemented [38]. Bioelectrical impedance analysis to estimate the lean muscle volume: Serial bioelectrical impedance analysis (S BIA ) was compared with magnetic resonance imaging (MRI) [39]. As a strong agreement between IV BIA and IV MRI was found, a specific conductivity constant (𝞼) was computed in order to assess the reliability of S BIA as a possible alternative to MRI.…”