Abstract
Objective MRI is widely used in several muscle disorders. Diffusion‐weighted imaging (DWI) is an emergent imaging modality sensitive to microstructural alterations in tissue. The apparent diffusion coefficient (ADC) is used to quantify the random motion of water molecules. Electromyography (EMG) is a clinically used diagnostic tool in myositis. The aim of this study was to elucidate possible associations between ADC values and EMG findings in myositis patients.MethodSeven patients (eight investigated muscles) with myositis (mean age 51.43 ± 19 years) were included in this study. The diagnosis was confirmed by histopathology in every case. DWI was obtained with a 1.5‐T scanner using two b‐values 0 and 1000 s/mm². In all patients, a needle electromyography (EMG) was performed within 3 days to the MRI. The following EMG parameters were studied: motor unit action potential (MUAP) amplitudes and durations, as well as pathological spontaneous activity. Spearman's correlation coefficient was used to analyze associations between investigated parameters.ResultsThe estimated mean ADC mean value was 1.51 ± 0.29 × 10−3 mm²/s, mean ADC min was 1.28 ± 0.27 × 10−3 mm²/s, and mean ADC max was 1.73 ± 0.28 × 10−3 mm²/s. Correlation analysis identified significant associations between ADC mean and duration of the MUAP (p = .78 P = .0279) and between ADC min and duration of the MUAP (p = .85, P = .01). There were no significant differences according to pathological spontaneous activity.Conclusion ADC mean and ADC min showed strong positive correlations with the duration of the MUAP in myositis patients. Both modalities might similarly reflect muscle fiber loss in myositis patients.
Highlights
Autoimmune myositis is a heterogeneous group of disorders of unknown etiology and can be classified into the following entities: polymyositis, dermatomyositis, inclusion body myositis, necrotizing autoimmune myositis, and overlap myositis (Dalakas, 2015)
Muscle fiber degeneration is accompanied by pathological spontaneous activity. It is yet unclear whether electrodiagnostic information about extracellular potential differences provided by EMG is associated with the random water motion in muscles measured by Diffusion-weighted imaging (DWI)
Due to the inflammation reaction muscle fibers degrade by apoptosis and necrosis (Dalakas, 2015)
Summary
Autoimmune myositis is a heterogeneous group of disorders of unknown etiology and can be classified into the following entities: polymyositis, dermatomyositis, inclusion body myositis, necrotizing autoimmune myositis, and overlap myositis (Dalakas, 2015). Diffusion-weighted imaging (DWI) has been evaluated to be a useful imaging tool in several muscle disorders such as tumors, inflammation, and myopathies (Partovi et al, 2015; Qi, Olsen, Price, Winston, & Park, 2008; Ran et al, 2016; Surov & Behrmann, 2014; Surov et al, 2015) It can be quantified with the apparent diffusion coefficient (ADC) reflecting the random water motion in tissue (Surov, Meyer, & Wienke, 2017). Muscle fiber degeneration is accompanied by pathological spontaneous activity It is yet unclear whether electrodiagnostic information about extracellular potential differences provided by EMG is associated with the random water motion in muscles measured by DWI. The purpose of this study was to elucidate possible associations between DWI and EMG in myositis patients
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
