Purpose: To establish the first comprehensive and standardized set of vagus nerve (VN) sonographic reference values across all the published studies that can be used to standardize and guide clinical practice and research.Methods: This systematic review includes all possible available data from a total of 27 studies and 21 of them were included in the meta-analysis having a total of 864 participants.
Results:The overall mean cross-sectional area ranged from 2.29 to 2.76 mm 2 for the right VN and from 1.83 to 2.23 mm 2 for the left VN with 95% confidence interval. Sonographic reference values of VN at common carotid artery bifurcation, thyroid gland, and cartilage as well as other anatomic landmarks were provided.
Conclusions:The mean cross-sectional area of the right VN of 2.53 mm 2 and the left one of 2.03 mm 2 can be considered as sonographic reference values in healthy adults. This review provides these reference values to be considered in the further sonographic evaluation of VNs.
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.
Introduction/Aims
Nerve ultrasound is useful in the diagnosis and follow‐up of peripheral nerve disorders in children. The aim of this study was to explore and analyze the current literature on nerve cross‐sectional area (CSA) in healthy children, with the goal of presenting reference values and discussing their implications.
Methods
We performed a systematic review and meta‐analysis of studies that reported ultrasound measurements of the upper or lower limb nerves in healthy children through a search of Web of Science, PubMed, Embase, and Scopus.
Results
Sixteen studies with measurements of 10 nerves covering a total of 5149 nerves measured in 823 healthy children (445 boys and 378 girls) were included. Mean nerve CSA increased with age in the median nerve at the middle and lower third of the upper arm, mid‐forearm, and distal wrist crease, the ulnar nerve at the middle third of the upper arm and elbow, the radial nerve at the spiral groove, and the tibial nerve at the popliteal fossa. Growth charts for nerve CSA for different age groups were developed.
Discussion
This meta‐analysis provides robust reference values for nerve CSA at different sites in children, and this can inform clinical practice and assist in identifying nerve enlargement. Moreover, it identifies the strength and quality of the current published data. We recommend future studies divide their samples into smaller age subgroups and standardize the anatomic site of measurement.
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