Muscle Sonography in Inclusion Body Myositis: A Systematic Review and Meta-Analysis of 944 Measurements.

Ramy Abdelnaby,Imene Maallem,Khaled Tarek Dardeer,Hazem Maher Gawish,Mohamed Ayman Ebrahim,Aya Moustafa Aboutaleb,Khaled Ashraf Mohamed,Yousef Tarek Sonbol,Anas Elgenidy,Jana Zschüntzsch,Hamed Amr Heikal,Mahmoud Mostafa Bedewy

doi:10.3390/cells11040600

Abstract

Inclusion body myositis (IBM) is a slowly progressive muscle weakness of distal and proximal muscles, which is diagnosed by clinical and histopathological criteria. Imaging biomarkers are inconsistently used and do not follow international standardized criteria. We conducted a systematic review and meta-analysis to investigate the diagnostic value of muscle ultrasound (US) in IBM compared to healthy controls. A systematic search of PubMed/MEDLINE, Scopus and Web of Science was performed. Articles reporting the use of muscle ultrasound in IBM, and published in peer-reviewed journals until 11 September 2021, were included in our study. Seven studies were included, with a total of 108 IBM and 171 healthy controls. Echogenicity between IBM and healthy controls, which was assessed by three studies, demonstrated a significant mean difference in the flexor digitorum profundus (FDP) muscle, which had a grey scale value (GSV) of 36.55 (95% CI, 28.65–44.45, p < 0.001), and in the gastrocnemius (GC), which had a GSV of 27.90 (95% CI 16.32–39.48, p < 0.001). Muscle thickness in the FDP showed no significant difference between the groups. The pooled sensitivity and specificity of US in the differentiation between IBM and the controls were 82% and 98%, respectively, and the area under the curve was 0.612. IBM is a rare disease, which is reflected in the low numbers of patients included in each of the studies and thus there was high heterogeneity in the results. Nevertheless, the selected studies conclusively demonstrated significant differences in echogenicity of the FDP and GC in IBM, compared to controls. Further high-quality studies, using standardized operating procedures, are needed to implement muscle ultrasound in the diagnostic criteria.

Highlights

Introduction distributed under the terms andInclusion body myositis (IBM) is one of the most common subtypes of idiopathic inflammatory myopathies (IIM) [1], primarily affecting those above 45 years of age
The results of our meta-analyses demonstrated an increased echogenicity in certain muscle groups compared to controls and could be used as a supportive criterion in the challenge of an early diagnosis for IBM
The echogenicity in IBM patients was increased with 36.55 grey scale value (GSV), 95% CI 28.65–44.45 and 27.9 GSV 95% CI, 16.32 −39.48 for the flexor digitorum profundus (FDP)

Summary

Introduction

Inclusion body myositis (IBM) is one of the most common subtypes of idiopathic inflammatory myopathies (IIM) [1], primarily affecting those above 45 years of age. It has a progressive course and affects skeletal muscles with a distinct pattern, [2] causing asymmetric muscle weakness [3,4,5] mainly in finger flexors and/or quadricep muscles [6]. This combination of weakness often results in loss of ambulation and independence, as well as the need for assertive devices and increased supportive care over the duration of the disease. The pathophysiology of IBM has not yet been clearly elucidated [12], several factors, e.g., genetic, aging, immunologic and mitochondrial dysfunction, have been suggested to play a role [13,14,15,16,17,18,19,20]

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