Neuromuscular ultrasound standardized scanning techniques and protocols: Expert panel recommendations.

Neuromuscular ultrasound has become an integral part of the diagnostic workup of neuromuscular disorders at many centers. Despite its growing utility, uniform standard scanning techniques do not currently exist. Scanning approaches for similar diseases vary in the literature creating heterogeneity in the studies as reported in several meta-analysis. Moreover, neuromuscular ultrasound experts including the group in this study have different views with regards to technical aspects, scanning protocols, and the parameters that should be assessed. Establishing standardized neuromuscular scanning protocols is essential for the development of the subspeciality to ensure uniform clinical and research practices. Therefore, we aimed to recommend consensus-based standardized scanning techniques and protocols for common neuromuscular disorders using the Delphi approach. A panel of 17 experts participated in the study, which consisted of three consecutive electronic surveys. The first survey included voting on six scanning protocols addressing the general scanning technique and five common categories of suspected neuromuscular disorders. The subsequent surveys focused on refining the protocols and voting on new steps, rephrased statements, or areas of non-agreement. A high degree of consensus was achieved on the general neuromuscular ultrasound scanning technique and the scanning protocols for focal mononeuropathies, brachial plexopathies, polyneuropathies, amyotophic lateral sclerosis, and muscle diseases. In this study, a group of neuromuscular ultrasound experts developed six consensus-based neuromuscular ultrasound scanning protocols that may serve as references for clinicians and researchers. The standardized protocols could also aid in achieving high-quality uniform neuromuscular ultrasound practices.

Short-term educational value of online neuromuscular ultrasound courses.

INTRODUCTION/AIMS: We have previously reported that online neuromuscular ultrasound courses are feasible and were found to be useful by most survey respondents. However, our previous report lacked objective assessment of the educational value of the courses. Therefore, we aimed in this study to evaluate the learning outcomes of online neuromuscular ultrasound courses. METHODS: Each of the basic and advanced courses featured one pre- and two post-course online knowledge tests. The percentage of corrected answers and the participants' scores in the three tests were calculated and compared. RESULTS: A total of 153 out of 277 course participants answered the course test. The mean percentage of correct answers were significantly higher in the second and first post-course tests compared to the pre-course test (Basic course test: 80.2 ± 14.8%, 75.5 ± 15.9%, 64.3 ± 19.1%, respectively; Advanced course test: 80.9 ± 20.1, 78.9 ± 15.2%, 69.5 ± 20.2%, respectively). The mean scores of the participants in the basic course test significantly improved in the first and second post-course tests (from 66.6% to 77.5% and from 67.2% to 80.2%, respectively) whereas those of the participants in the advanced course test significantly improved in the first post-course test only (from 76.3% to 85.4%). DISCUSSION: This report demonstrates the capability of online neuromuscular ultrasound courses, particularly the basic-level courses, to enhance knowledge. This information can further help integrate virtual neuromuscular ultrasound teaching as a standard complementary educational format together with supervised in-person or remote hands-on training.

Sonographic reference values of cranial nerve size: A systematic review and meta-analysis.

INTRODUCTION/AIMS: Ultrasonography of the cranial nerves has recently gained attention for assessment of inflammatory, compressive, or degenerative neuropathies. However, sonographic reference values of cranial nerves have received less attention than those of peripheral nerves. In this systematic review and meta-analysis we aimed to provide current evidence of sonographic reference values for cranial nerve size. METHODS: By searching Medline (via PubMed), Scopus, Embase, Cochrane Central Register of Controlled Trials (CENTRAL), and Web of Science, we conducted a systematic review and meta-analysis of studies that reported ultrasound measurements of the facial, spinal accessory, and hypoglossal nerves in healthy adults. We included studies that reported either the sonographic cross-sectional area (CSA) or the nerve diameter; the included nerves were subgrouped according to the site of nerve measurement. RESULTS: Fourteen studies with a total of 661 participants and 1437 ultrasound nerve measurements met the inclusion criteria. The anatomical sites for each nerve were combined to provide single-nerve mean measurements. We found an overall mean nerve diameter of 0.80 mm for the facial nerve, 0.63 mm for the spinal accessory nerve, and 1.82 mm2 for hypoglossal nerve CSA. DISCUSSION: This meta-analysis provides reference values for the diameter and cross-sectional area of the facial, spinal accessory, and hypoglossal nerves at different sites, which can be used as guidance in clinical practice to detect pathological changes in cranial nerve size in cranial neuropathies. We recommend further validation in large-scale studies as well as standardization of the scanning protocols.

Virtual neuromuscular ultrasound courses during COVID-19 pandemic: Leveraging technology to enhance learning opportunities.

INTRODUCTION/AIMS: Hands-on supervised training is essential for learning diagnostic ultrasound. Unfortunately, the coronavirus disease 2019 (COVID-19) pandemic led to suspension of in-person training courses. As a result, many hands-on training courses were converted into virtual courses during the pandemic. Several reports regarding virtual ultrasound courses exist, but none has addressed virtual neuromuscular ultrasound courses, their design, or participants' views of this form of training. Therefore, the aims of this study were: (1) to determine the feasibility of conducting virtual neuromuscular ultrasound courses during the COVID-19 pandemic; and (2) to report the positive and negative aspects of the courses through the analyses of the responses of post-course surveys. METHODS: Two virtual neuromuscular ultrasound courses, basic and intermediate level, were conducted by the Egyptian Neuromuscular Ultrasound society during August 2020. Post-course, the attendees were directed to an electronic survey that consisted of eight questions. Ninety-three responses (23.8%) were obtained from the survey of the basic course and 156 responses (44.4%) were obtained from the survey of the intermediate course. RESULTS: Ninety-eight percent of the respondents to basic course surveys, and 100% of the respondents to the intermediate course survey found the courses useful or very useful. DISCUSSION: This report demonstrates the utility of virtual neuromuscular ultrasound courses for those participants willing to respond to a survey and describes a proposed design for such courses. Although hands-on supervised ultrasound training is ideal, virtual courses can be useful alternatives to in-person training when in-person interaction is restricted.

Neuromuscular ultrasound competency assessment: Consensus-based survey.

Neuromuscular ultrasound is a rapidly evolving specialty with direct application for patient care. Competency assessment is an essential standard needed to ensure quality for practitioners, particularly for those newly acquiring skills with the technique. Our aim was to survey experts' opinions regarding physician competency assessment of neuromuscular ultrasound and to identify minimal competency of knowledge and skills. The opinions of 18 experts were obtained through the Delphi method using two consecutive electronic surveys. A high degree of consensus was achieved on items regarding framework and the conduct of neuromuscular ultrasound assessment and the knowledge and skills that a candidate needs to attain minimal competency in neuromuscular ultrasound. In this study, a group of neuromuscular ultrasound experts developed a general framework for neuromuscular ultrasound competency assessment and recommended testable areas of knowledge and skills suitable for establishing minimal competency.

Guidelines for neuromuscular ultrasound training.

Neuromuscular ultrasound has become an essential tool in the diagnostic evaluation of various neuromuscular disorders, and, as such, there is growing interest in neuromuscular ultrasound training. Effective training is critical in mastering this modality. Our aim was to develop consensus-based guidelines for neuromuscular ultrasound training courses. A total of 18 experts participated. Expert opinion was sought through the Delphi method using 4 consecutive electronic surveys. A high degree of consensus was achieved with regard to the general structure of neuromuscular ultrasound training; the categorization of training into basic, intermediate, and advanced levels; the learning objectives; and the curriculum for each level. In this study, a group of neuromuscular ultrasound experts established consensus-based guidelines for neuromuscular ultrasound training. These guidelines can be used in the development of the specialty and the standardization of neuromuscular ultrasound training courses and workshops.

Indications for neuromuscular ultrasound: Expert opinion and review of the literature.

Over the last two decades, dozens of applications have emerged for ultrasonography in neuromuscular disorders. We wanted to measure its impact on practice in laboratories where the technique is in frequent use. After identifying experts in neuromuscular ultrasound and electrodiagnosis, we assessed their use of ultrasonography for different indications and their expectations for its future evolution. We then identified the earliest papers to provide convincing evidence of the utility of ultrasound for particular indications and analyzed the relationship of their date of publication with expert usage. We found that experts use ultrasonography often for inflammatory, hereditary, traumatic, compressive and neoplastic neuropathies, and somewhat less often for neuronopathies and myopathies. Usage significantly correlated with the timing of key publications in the field. We review these findings and the extensive evidence supporting the value of neuromuscular ultrasound. Advancement of the field of clinical neurophysiology depends on widespread translation of these findings.

Diagnostic Ultrasound of the Vagus Nerve in Patients with Diabetes.

BACKGROUND AND PURPOSE: Autonomic neuropathy is a serious and common complication of diabetes mellitus. The vagus nerve is the longest autonomic nerve, and may be affected in diabetes as a part of generalized neuropathy. Our objective was to assess for possible sonographic changes of the vagus nerve in diabetic patients. METHODS: The vagus nerve was bilaterally scanned in 20 healthy volunteers and 54 patients with diabetes in the axial plane at the lateral neck. RESULTS: The mean cross-sectional area of the vagus nerve was significantly smaller in patients with diabetes compared with controls. Receiver operating characteristic curve analyses revealed an area under the curve of .96, and an optimum cutoff point of 3 mm2 with a sensitivity of 85.2% and specificity of 100%. CONCLUSIONS: This study demonstrates a degree of vagus nerve atrophy in patients with diabetes. This finding may have relevance in the diagnosis and treatment of diabetic neuropathy if further validated.

Proposed Sonographic Criteria for the Diagnosis of Idiopathic Tarsal Tunnel Syndrome.

OBJECTIVE: To propose new sonographic criteria for the diagnosis of idiopathic tarsal tunnel syndrome (TTS). DESIGN: Prospective case-control study. SETTING: Academic referral center. PARTICIPANTS: Adult healthy volunteers (n=17) and adult patients (n=14) with electrodiagnostically proven idiopathic TTS (mean age, 43.4±8.7y; height, 161.4±7.0cm; weight, 90.6±13.9kg) (N=31). The exclusion criteria were patients with diabetes, neurological disorders, associated ankle and/or foot disorders, electrodiagnostic evidence of a widespread lesion, or feet that were electrophysiologically negative for TTS or with structural abnormalities detected via ultrasound imaging. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Tibial nerve CSA at the proximal tarsal tunnel, tibial nerve CSA within the tunnel, within tunnel-to-proximal tunnel CSA ratio. RESULTS: There was a significant difference in the within tunnel CSA and within tunnel-to-proximal tunnel CSA ratio between the TTS group and controls (P=.002 and P=.001, respectively). The optimum cutoff value was 19mm(2) for the within tunnel CSA and 1 for the within tunnel-to-proximal tunnel CSA ratio. Sensitivities were 61% and 74%, respectively. CONCLUSIONS: The within tunnel-to-proximal tunnel CSA ratio and the within tunnel CSA are the most accurate sonographic parameters and can be helpful in the assessment of idiopathic TTS.

A Pilot Study of Diagnostic Neuromuscular Ultrasound in Bell's Palsy.

BACKGROUND AND PURPOSE: Neuromuscular ultrasound of the cranial nerves is an emerging field which may help in the assessment of cranial neuropathies. The aim of this study was to evaluate the role of neuromuscular ultrasound in Bell's palsy. A second objective was to assess the possibility of any associated vagus nerve abnormality. METHODS: Twenty healthy controls and 12 Bell's palsy patients were recruited. The bilateral facial nerves, vagus nerves, and frontalis muscles were scanned using an 18 MHz linear array transducer. Facial nerve diameter, vagus nerve cross-sectional area, and frontalis thickness were measured. RESULTS: Mean facial nerve diameter was .8 ± .2 mm in controls and 1.1 ± .3 mm in patients group. The facial nerve diameter was significantly larger in patients than controls (P = .006, 95% CI for the difference between groups of .12-.48), with a significant side-to-side difference in patients as well (P = .004, 95% CI for side-to-side difference of .08-.52). ROC curve analysis of the absolute facial nerve diameter revealed a sensitivity of 75% and a specificity of 70%. No significant differences in vagus nerve cross-sectional area or frontalis thickness were detected between patients and controls. CONCLUSIONS: Ultrasound can detect facial nerve enlargement in Bell's palsy and may have a role in assessment, or follow-up, of Bell's palsy and other facial nerve disorders. The low sensitivity of the current technique precludes its routine use for diagnosis, however, this study demonstrates its validity and potential for future research.

Neuromuscular ultrasound of cranial nerves.

Ultrasound of cranial nerves is a novel subdomain of neuromuscular ultrasound (NMUS) which may provide additional value in the assessment of cranial nerves in different neuromuscular disorders. Whilst NMUS of peripheral nerves has been studied, NMUS of cranial nerves is considered in its initial stage of research, thus, there is a need to summarize the research results achieved to date. Detailed scanning protocols, which assist in mastery of the techniques, are briefly mentioned in the few reference textbooks available in the field. This review article focuses on ultrasound scanning techniques of the 4 accessible cranial nerves: optic, facial, vagus and spinal accessory nerves. The relevant literatures and potential future applications are discussed.

Sonographic characteristics of the facial nerve in healthy volunteers.

INTRODUCTION: Peripheral nerve ultrasound has become an effective imaging technique. However, imaging of cranial nerves, especially in healthy volunteers, has received minimal attention. The objectives of this study were to describe the sonographic characteristics of the facial nerve and to establish average values of its diameter. METHODS: The extra-cranial part of the facial nerve was scanned bilaterally along its longitudinal axis inside the parotid gland using a 13-MHz probe in 50 healthy adults. The diameter was measured at the nerve's thickest region. RESULTS: The facial nerve appeared as a thin, tubular, hypoechoic structure inside the parotid gland. The mean facial nerve diameter was 0.5 ± 0.1 mm, and the mean side-to-side difference in diameter was 0.1 ± 0.1 mm. CONCLUSIONS: The average facial nerve diameter values may provide help with identification of nerve abnormalities using ultrasound.