title: The Effect of Subcutaneous Fat on Electrical Impedance Myography: Electrode Configuration and Multi-Frequency Analyses.
abstract: This study investigates the impact of the subcutaneous fat layer (SFL) thickness on localized electrical impedance myography (EIM), as well as the effects of different current electrodes, varying in distance and direction, on EIM output. Twenty-three healthy subjects underwent localized multi-frequency EIM on their biceps brachii muscles with a hand-held electrode array. The EIM measurements were recorded under three different configurations: wide (or outer) longitudinal configuration 6.8 cm, narrow (or inner) longitudinal configuration 4.5 cm, and narrow transverse configuration 4.5 cm. Ultrasound was applied to measure the SFL thickness. Coefficients of determination (R2) of three EIM variables (resistance, reactance, and phase) and SFL thickness were calculated. For the longitudinal configuration, the wide distance could reduce the effects of the subcutaneous fat when compared with the narrow distance, but a significant correlation still remained for all three EIM parameters. However, there was no significant correlation between SFL thickness and reactance in the transverse configuration (R2 = 0.0294, p = 0.434). Utilizing a ratio of 50kHz/100kHz phase was found to be able to help reduce the correlation with SFL thickness for all the three configurations. The findings indicate that the appropriate selection of the current electrode distance, direction and the multi-frequency phase ratio can reduce the impact of subcutaneous fat on EIM. These settings should be evaluated for future clinical studies using hand-held localized arrays to perform EIM.
authors.affiliation: Department of Rehabilitation Medicine, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China.|Department of Physical Medicine and Rehabilitation, University of Texas Health Science Center at Houston, Houston, Texas, United States of America.|TIRR Memorial Hermann Research Center, Houston, Texas, United States of America.
authors.forename: Le
authors.initials: L
authors.lastname: Li
authors.affiliation: Department of Physical Medicine and Rehabilitation, University of Texas Health Science Center at Houston, Houston, Texas, United States of America.|TIRR Memorial Hermann Research Center, Houston, Texas, United States of America.
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Li
authors.affiliation: Guangdong Provincial Work Injury Rehabilitation Center, Guangzhou, Guangdong, China.|Department of Physical Medicine and Rehabilitation, University of Texas Health Science Center at Houston, Houston, Texas, United States of America.|TIRR Memorial Hermann Research Center, Houston, Texas, United States of America.
authors.forename: Huijing
authors.initials: H
authors.lastname: Hu
authors.affiliation: Department of Physical Medicine and Rehabilitation, University of Texas Health Science Center at Houston, Houston, Texas, United States of America.|TIRR Memorial Hermann Research Center, Houston, Texas, United States of America.
authors.forename: Henry
authors.initials: H
authors.lastname: Shin
authors.affiliation: Guangdong Provincial Work Injury Rehabilitation Center, Guangzhou, Guangdong, China.|Department of Physical Medicine and Rehabilitation, University of Texas Health Science Center at Houston, Houston, Texas, United States of America.|TIRR Memorial Hermann Research Center, Houston, Texas, United States of America.
authors.forename: Ping
authors.identifier: 0000-0002-4394-2677
authors.initials: P
authors.lastname: Zhou
mesh_terms: D000328:Adult; D017097:Electric Impedance; D004566:Electrodes; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000000981:diagnostic imaging / Q000502:physiology*; D009213:Myography / Q000379:methods*; D050151:Subcutaneous Fat / Q000000981:diagnostic imaging / Q000502:physiology*; D055815:Young Adult