Quantitative Ultrasound Imaging to Assess Skeletal Muscles in Adults with Multiple Sclerosis: A Feasibility Study

Abstract

Objectives The aim of this study was to assess the feasibility of quantitative ultrasound imaging (QUI) in assessing the biceps brachii muscle and gastrocnemius muscle in adults with multiple sclerosis (MS). Methods From May to October 2018, we prospectively performed B‐mode ultrasound imaging and ultrasound strain elastography of the biceps brachii muscle and gastrocnemius muscle in 24 patients with MS and 10 age‐matched healthy volunteers. ImageJ (https://imagej.nih.gov/ij) was used to assess the muscle pixel intensity in grayscale images. Using 2‐dimensional speckle‐tracking software, we estimated the muscle axial peak strain (maximum deformation) produced by manual compression with an ultrasound transducer and the muscle longitudinal peak strain (maximum displacement) produced by passive elbow and ankle movements. Muscle QUI parameters used in the study included the mean pixel intensity, axial peak strain ratio (SR = muscle strain/subcutaneous tissue strain), and longitudinal peak SR. Statistical analyses included 1‐way analysis of variance and a post hoc test to examine the differences in QUI parameters among 3 groups (1, affected muscle in patients with MS; 2, unaffected muscle in patients with MS; and 3, healthy muscle in controls) and, in all paired groups, an unpaired t test to compare the muscle SR in patients with MS with a Modified Ashworth Scale (MAS) score of 1 or higher to those with an MAS score of 0. Results The mean age of the 24 patients with MS was 43 years, and all patients and volunteers were female. We observed a significant difference in QUI parameters among the affected muscle in MS, unaffected muscle in MS, and healthy muscle in all paired groups and in patients with MS between an MAS score of 1 or higher and an MAS score of 0 (all P < .05). Interobserver and intraobserver variability in performing QUI was good (intraclass correlation coefficients >0.75). Conclusions Our results suggest that QUI is feasible to assess muscle echogenicity and mechanical behaviors in adult MS.

Intra-session and inter-rater reliability of spatial frequency analysis methods in skeletal muscle

“…This is an important factor when adapting this method for assessment of muscle structure between different muscles and within different locations along the length of the same muscle. The high ICC values for the intra-rater reliability are consistent with some findings using firstorder gray-scale statistics and backscatter analysis in healthy subjects [6,23,37,38] and the SFA method in Achilles tendons [39].…”

“…A linear array transducer (2-10 MHz) was used with the following parameters: imaging depth of 5 cm, dual transmit foci depth of 2 and 3 cm (corresponding to approximately the center of the muscle [23]), and gain of 38%, as this was determined from preliminary image acquisitions to result in clear images without image saturation. All ultrasound settings were kept constant for all image acquisitions [6,24].…”

“…Imaging modalities such as ultrasound (US) are typically used in conjunction with non-imaging clinical tests to aid in diagnoses of various musculoskeletal (MSK) conditions [1,2]. Measures of quantitative US, such as echo-intensity or first-order statistical analysis of individual image pixels [3][4][5][6][7], have been correlated to muscle quality and function in both animal models and humans [6,[8][9][10][11].…”

Stiffness and echogenicity: Development of a stiffness-echogenicity matrix for clinical problem solving

“…However, in central neurogenic disorders such stroke and multiple sclerosis, the degree of stiffness tends to be greater, while the echogenicity may be normal or slightly increased, presenting as grade 3D on the SEM. Gao et al 52 described a significant difference in muscle strain ratios in the affected muscles of patients with multiple sclerosis with Modified Ashworth Scale (MAS) score of 1 or higher. In patients with late central neurogenic conditions, such as those with severe spasticity, the combination of hyper-echogenicity and stiffness is well recognized, 53,54 and may present as grade 4D.…”

3D Muscle Deformation Mapping at Submaximal Isometric Contractions: Applications to Aging Muscle

“…However, it is not a direct measure of muscle strain. Ultrasound (US) strain imaging has been used to measure strain and strain rate primarily in cardiac muscle ( Bansal et al, 2010 ; Gorcsan and Tanaka, 2011 ; Mondillo et al, 2011 ; Yamada et al, 2014 ) though there have been several applications to skeletal muscle dynamic imaging as well ( Lopata et al, 2010 ; Gijsbertse et al, 2017 ; Gao et al, 2018 , 2019 ; Frich et al, 2019 ). Most ultrasound studies are performed in 2D that allows 2D strain estimation; however, some studies have extended it to bi-plane US studies where strain can be assessed in three orthogonal directions ( Gijsbertse et al, 2017 ).…”