Muscle ultrasound in myopathies.

PURPOSE OF REVIEW: This review highlights recent developments in the field of muscle ultrasound (MUS) for the diagnosis and follow up of muscle disorders. RECENT FINDINGS: The diagnostic screening capacity of quantitative grayscale analysis is still sufficient to assess children suspected of a neuromuscular disorder. A combination of visual and quantitative assessment is advised for optimal interpretation. MUS was more sensitive but less specific than MRI for detecting pathology in limb girdle dystrophies and inflammatory myopathies. New techniques such as shearwave elastography and artificial intelligence algorithms for automated image segmentation show promise but need further development for use in everyday practice.Muscle ultrasound has high correlations with clinical measures of function in skeletal and respiratory muscles and the orofacial region, in most of the myopathies and dystrophies studied. Over time, imaging changes precede changes in clinical status, making them attractive for biomarker use in trials. In Duchenne muscular dystrophy MUS was also responsive to the effects of steroid treatment. SUMMARY: Muscle ultrasound is a sensitive technique to diagnose and follow up of skeletal, facial and respiratory muscles in neuromuscular disorders. Its role is both complementary to and partially overlapping with that of MRI.

Nerve enlargement in patients with Noonan syndrome: A retrospective cohort study.

Noonan syndrome (NS) is an autosomal dominant condition characterized by facial dysmorphism, congenital heart disease, development delay, growth retardation and lymphatic disease. It is caused by germline pathogenic variants in genes encoding proteins in the Ras/mitogen-activated protein kinase signaling pathway. Nerve enlargement is not generally considered as a feature of NS, although some cases have been reported. High-resolution nerve ultrasound enables detailed anatomical assessment of peripheral nerves and can show enlarged nerves. This retrospective cohort study aims to describe the sonographic findings of patients with NS performed during a 1-year time period. Data on the degree of enlargement, the relation to increasing age, pain in extremities, genotype on the gene level and clinical features were collected. Twenty-nine of 93 patients visiting the NS Center of Expertise of the Radboud University Medical Center Nijmegen underwent high-resolution ultrasound. In 24 patients (83%) nerve enlargement was found. Most of them experienced pain. We observed a weak correlation with increasing age and the degree of nerve enlargement but no association with pain, genotype at the gene level or clinical features. This study shows that patients with NS have a high predisposition for sonographic nerve enlargement and that the majority experience pain.

Comparison of muscle ultrasound and needle electromyography findings in neuromuscular disorders.

INTRODUCTION/AIMS: Needle electromyography (EMG) and muscle ultrasound can be used to evaluate patients with suspected neuromuscular disorders. The relation between muscle ultrasound pathology and the corresponding needle EMG findings is unknown. In this study we compared the results of concurrent ultrasound and needle EMG examinations in patients suspected of a neuromuscular disorder. METHODS: Retrospective data from 218 patients with pairwise ultrasound and EMG results of 796 muscles were analyzed. We compared overall quantitative and visual muscle ultrasound results to EMGs with neurogenic and myopathic abnormalities and assessed the congruency of both methods in the different clinical diagnosis categories. RESULTS: In muscles of patients with a neuromuscular disorder, abnormalities were found with EMG in 71.8%, and quantitative and visual muscle ultrasound results were abnormal in 19.3% and 35.4% respectively. In muscles with neurogenic EMG abnormalities, quantitative and visual muscle ultrasound results were abnormal in 18.9% versus 35.6%, increasing up to 43.7% versus 87.5% in muscles with the most pronounced signs of denervation. Congruency of EMG and ultrasound was better for more proximal and cranial muscles than for muscles in the hand and lower limb. DISCUSSION: Needle EMG and muscle ultrasound typically produce disparate results and identify different aspects of muscle pathology. Muscle ultrasound seems less suited for detecting mild neurogenic abnormalities. As the severity of neurogenic needle EMG abnormalities increased, muscle ultrasound abnormalities were also increasingly found. Visual analysis seems better suited than grayscale quantification for detecting neurogenic abnormalities.

Electrodiagnostic studies and new diagnostic modalities for evaluation of peripheral nerve disorders.

Electrodiagnostic studies (EDx) are frequently performed in the diagnostic evaluation of peripheral nerve disorders. There is increasing interest in the use of newer, alternative diagnostic modalities, in particular imaging, either to complement or replace established EDx protocols. However, the evidence to support this approach has not been expansively reviewed. In this paper, diagnostic performance data from studies of EDx and other diagnostic modalities in common peripheral nerve disorders have been analyzed and described, with a focus on radiculopathy, plexopathy, compressive neuropathies, and the important neuropathy subtypes of Guillain-Barré syndrome, chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), vasculitic neuropathy and diabetic neuropathy. Overall EDx retains its place as a primary diagnostic modality in the evaluated peripheral nerve disorders. Magnetic resonance imaging and ultrasound have developed important complementary diagnostic roles in compressive and traumatic neuropathies and atypical CIDP, but their value is more limited in other neuropathy subtypes. Identification of hourglass constriction in nerves of patients with neuralgic amyotrophy may have therapeutic implications. Investigation of radiculopathy is confounded by poor correlation between clinical features and imaging findings and the lack of a diagnostic gold standard. There is a need to enhance the literature on the utility of these newer diagnostic modalities.

The other face of facioscapulohumeral muscular dystrophy: Exploring orofacial weakness using muscle ultrasound.

INTRODUCTION/AIMS: One of the most distinct clinical features of facioscapulohumeral muscular dystrophy (FSHD) is facial weakness. It leads to diminished facial expression and functional impairments. Despite its clinical relevance, little else is known about orofacial muscle involvement. We therefore evaluated orofacial muscle involvement in a sizeable cohort of FSHD participants with muscle ultrasound. METHODS: Muscle ultrasound images of the following orofacial muscles were scored visually and quantitatively: depressor anguli oris (DAO), orbicularis oris (OO), buccinator, temporalis, masseter, digastric, zygomaticus major and minor bilaterally, and the geniohyoid. Reliability analyses of both visual and quantitative evaluations were performed. Ultrasound results were correlated with other measures: the FSHD clinical score, facial weakness score, and facial function scale. RESULTS: We included 107 FSHD participants (male 54%; age 52 ± 14 years), of whom 92% showed signs of facial weakness. The reliability of visual ultrasound analysis varied widely (κ 0.0-1.0). Quantitative ultrasound reliability was high (intraclass correlation analysis ≥ 0.96). The DAO, buccinator, OO, temporalis, and zygomaticus minor muscles were affected most often (15%-39%). The digastric, geniohyoid, zygomaticus major, and masseter muscles were least often affected (<5%). The ultrasound compound score correlated weakly to moderately with other outcome measures used (ρ = 0.3-0.7). DISCUSSION: This study adds to the understanding of orofacial weakness in FSHD, confirming the involvement of the muscles of facial expression in FSHD using ultrasound. We showed that orofacial muscle ultrasound is feasible and reliable when quantitatively assessed. Future studies should evaluate orofacial muscle ultrasound longitudinally, alongside clinical and patient-reported facial weakness outcome measures, to assess their potential as outcome measures.

A prospective case series to evaluate subcostal nerve injury with high-resolution ultrasound in posterior retroperitoneoscopic adrenalectomy.

BACKGROUND: Posterior retroperitoneoscopic adrenalectomy has several advantages over transabdominal laparoscopic adrenalectomy regarding operating time, blood loss, postoperative pain, and recovery. However, postoperatively several patients report chronic pain or hypoesthesia. We hypothesized that these symptoms may be the result of damage to the subcostal nerve, because it passes the surgical area. METHODS: A prospective single-center case series was performed in adult patients without preoperative pain or numbness of the abdominal wall who underwent unilateral posterior retroperitoneoscopic adrenalectomy. Patients received pre- and postoperative questionnaires and a high-resolution ultrasound scan of the subcostal nerve and abdominal wall muscles was performed before and directly after surgery. Clinical evaluation at 6 weeks was performed with repeat questionnaires, physical examination, and high-resolution ultrasound. Long-term recovery was evaluated with questionnaires, and photographs from the patients were examined for abdominal wall asymmetry. RESULTS: A total of 25 patients were included in the study. There were no surgical complications. Preoperative visualization of the subcostal nerve was possible in all patients. At 6 weeks, ultrasound showed nerve damage in 15 patients, with no significant association between nerve damage and postsurgical pain. However, there was a significant association between nerve damage and hypoesthesia (p = 0.01), sensory (p < 0.001), and motor (p < 0.001) dysfunction on physical examination. After a median follow-up of 18 months, 5 patients still experienced either numbness or muscle weakness, and one patient experienced chronic postsurgical pain. CONCLUSION: In this exporatory case series the incidence of postoperative damage to the subcostal nerve, both clinically and radiologically, was 60% after posterior retroperitoneoscopic adrenalectomy. There was no association with pain, and the spontaneous recovery rate was high.

Effectiveness of an outpatient rehabilitation programme in patients with neuralgic amyotrophy and scapular dyskinesia: a randomised controlled trial.

BACKGROUND: Neuralgic amyotrophy (NA) is an acute inflammation of nerves within the brachial plexus territory leading to severe pain and multifocal paresis resulting in >60% of patients having residual complaints and functional limitations correlated with scapular dyskinesia. Our primary aim was to compare the effects of multidisciplinary rehabilitation (MR), focused on motor relearning to improve scapular dyskinesia and self-management strategies for reducing pain and fatigue, with usual care (UC) on shoulder, arm and hand functional capability in patients with NA. METHODS: In a non-blinded randomised controlled trial (RCT), patients with NA (aged≥18 years, scapular dyskinesia, >8 weeks after onset) were randomised to either an MR or an UC group. MR consisted of a diagnostic multidisciplinary consultation and eight sessions of physical and occupational therapy. Primary outcome was functional capability of the shoulder, arm and hand assessed with the Shoulder Rating Questionnaire-Dutch Language Version (SRQ-DLV). RESULTS: We included 47 patients with NA; due to drop-out, there were 22 participants in MR and 15 in UC for primary analysis. The mean group difference adjusted for sex, age and SRQ-DLV baseline score was 8.60 (95%CI: 0.26 to 16.94, p=0.044). The proportion attaining a minimal clinically relevant SRQ-DLV improvement (≥12) was larger for the MR group (59%) than the UC group (33%) with a number needed to treat of 4. CONCLUSION: This RCT shows that an MR programme focused on motor relearning to improve scapular dyskinesia, combined with self-management strategies for reducing pain and fatigue, shows more beneficial effects on shoulder, arm and hand functional capability than UC in patients with NA. TRIAL REGISTRATION NUMBER: NCT03441347.

Neuromuscular ultrasound as a marker for inherited sensory neuronopathy.

A review and detailed analysis of the literature over the past two decades has revealed a unique ultrasound feature of pathologically "small" nerves in inherited sensory neuronopathies. Although sample sizes were limited, due to the rarity of these diseases, this characteristic ultrasound finding has been consistently reported across a variety of inherited diseases that affect the dorsal root ganglia. Direct comparisons with both acquired and inherited diseases that primarily affect the axons in the peripheral nerves showed that the ultrasound finding of abnormally "small" cross-sectional areas (CSAs) in mixed nerves of the upper limbs has a high diagnostic accuracy for inherited sensory neuronopathy. Based on this review, ultrasound CSA of the mixed upper limb nerves can be proposed as a marker for inherited sensory neuronopathy.

Validity and reliability of visual assessment of orofacial muscle ultrasound images using a modified Heckmatt scale.

INTRODUCTION/AIMS: Orofacial muscle ultrasound images can be evaluated quantitatively or using a visual grading system. Quantitative muscle ultrasound (QMUS) is currently the most sensitive technique to detect pathology, but can be time-consuming. The aim of this study was to investigate the validity and reliability of two visual grading systems (the original Heckmatt scale or a modified 3-point version) for the optimal grading of orofacial muscle images. METHODS: A retrospective, comparative, reliability and validity study was performed. Ultrasound images of the digastric, geniohyoid, masseter, temporalis muscles, and intrinsic muscles of the tongue of healthy participants and of patients (suspected of) having a neuromuscular disease were included. QMUS was used as the "gold standard." Two expert raters and one inexperienced rater rated all ultrasound images using both visual grading systems. RESULTS: A total of 511 ultrasound images were included. Criterion validity showed Spearman rho correlation coefficients of >0.59. Construct validity analysis showed strong to very strong associations between the visual grading systems and mastication and/or swallowing. Inter- and intrarater reliability of the original Heckmatt scale and the modified scale were good and comparable. Rater experience had a beneficial effect on the interrater reliability of both scales. DISCUSSION: Both the original Heckmatt and the modified Heckmatt scale are valid and reliable tools for the visual grading of orofacial ultrasound images. The modified Heckmatt scale, with only three grades and including an "uncertain" category, is considered easier to use in clinical practice.

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.

A standardized ultrasound approach in neuralgic amyotrophy.

Neuralgic amyotrophy (NA), also referred to as idiopathic brachial plexitis and Parsonage-Turner syndrome, is a peripheral nerve disorder characterized by acute severe shoulder pain followed by progressive upper limb weakness and muscle atrophy. While NA is incompletely understood and often difficult to diagnose, early recognition may prevent unnecessary tests and interventions and, in some situations, allow for prompt treatment, which can potentially minimize adverse long-term sequalae. High-resolution ultrasound (HRUS) has become a valuable tool in the diagnosis and evaluation of NA. Pathologic HRUS findings can be grouped into four categories: nerve swelling, swelling with incomplete constriction, swelling with complete constriction, and fascicular entwinement, which may represent a continuum of pathologic processes. Certain ultrasound findings may help predict the likelihood of spontaneous recovery with conservative management versus the need for surgical intervention. We recommend relying heavily on history and physical examination to determine which nerves are clinically affected and should therefore be assessed by HRUS. The nerves most frequently affected by NA are the suprascapular, long thoracic, median and anterior interosseous nerve (AIN) branch, radial and posterior interosseous nerve (PIN) branch, axillary, spinal accessory, and musculocutaneous. When distal upper limb nerves are affected (AIN, PIN, superficial radial nerve), the lesion is almost always located in their respective fascicles within the parent nerve, proximal to its branching point. The purpose of this review is to describe a reproducible, standardized, ultrasonographic approach for evaluating suspected NA, and to share reliable techniques and clinical considerations when imaging commonly affected nerves.

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.

Effects of Sodium Lactate Infusion in Two Girls with Glucose Transporter 1 Deficiency Syndrome.

BACKGROUND: Glucose is an important fuel for the brain. In glucose transporter 1 deficiency syndrome (GLUT1DS), the transport of glucose across the blood-brain barrier is limited. Most individuals with GLUT1DS present with developmental problems, epilepsy, and (paroxysmal) movement disorders, and respond favorably to the ketogenic diet. Similar to ketones, lactate is an alternative energy source for the brain. The aim of this study is to investigate whether intravenous infusion of sodium lactate in children with GLUT1DS has beneficial effects on their epilepsy. METHODS: We performed a proof of principle study with two subjects with GLUT1DS who were not on a ketogenic diet and suffered from absence epilepsy. After overnight fasting, sodium lactate (600 mmol/L) was infused during 120 minutes, under video electroencephalographic (EEG) recording and monitoring of serum lactate, glucose, electrolytes, and pH. Furthermore, the EEGs were compared with pre-/postprandial EEGs of both subjects, obtained shortly before the study. RESULTS: Fasting EEGs of both subjects showed frequent bilateral, frontocentral polyspike and wave complexes. In one subject, no more epileptic discharges were seen postprandially and after the start of lactate infusion. The EEG of the other subject did not change, neither postprandially nor after lactate infusion. Serum pH, lactate, and sodium changed temporarily during the study. CONCLUSION: This study suggests that sodium lactate infusion is possible in individuals with GLUT1DS, and may have potential therapeutic effects. Cellular abnormalities, beyond neuronal energy failure, may contribute to the underlying disease mechanisms of GLUT1DS, explaining why not all individuals respond to the supplementation of alternative energy sources.

Hypertrophic neuropathy: a possible cause of pain in children with Noonan syndrome and related disorders.

This study is aimed at describing the findings of high-resolution nerve ultrasound in children with Noonan syndrome (NS) and related disorders experiencing pain in their legs. This retrospective cohort study was conducted in the NS expert center of the Radboud University Medical Center in the Netherlands. Patients were eligible if they were younger than 18 years, clinically and genetically diagnosed with NS or a NS related disorder, and experienced pain in their legs. Anamneses and physical examination were performed in all children. In addition, high-resolution nerve ultrasound was used to assess nerve hypertrophy and, if needed, complemented spinal magnetic resonance imaging was performed. Over a period of 6 months, four children, three with NS and one child with NS with multiple lentigines, who experienced pain of their legs were eligible for inclusion. Muscle weakness was found in two of them. High-resolution nerve ultrasound showed (localized) hypertrophic neuropathy in all patients. One child underwent additional spinal magnetic resonance imaging, which showed profound thickening of the nerve roots and plexus.  Conclusion: In the four children included with a NS and related disorders, pain was concomitant with nerve hypertrophy, which suggests an association between these two findings. The use of high-resolution nerve ultrasound and spinal magnetic resonance imaging might result in better understanding of the nature of this pain and the possible association to nerve hypertrophy in patients with NS and related disorders. What is Known: • Children with Noonan syndrome and related disorders may report pain in their legs, which is often interpreted as growing pain. • Some adults with Noonan syndrome and related disorders have hypertrophic neuropathy as a possible cause of neuropathic pain. What is New: • This is the first study using high-resolution nerve ultrasound in children with Noonan syndrome and related disorders experiencing pain in their legs. • Hypertrophic neuropathy was diagnosed as possible cause of pain in four children with Noonan syndrome and related disorders.

Neurological features of Noonan syndrome and related RASopathies: Pain and nerve enlargement characterized by nerve ultrasound.

This study aimed to assess the nature of peripheral nervous system (PNS) involvement in three patients with Noonan syndrome (NS) or NS with multiple lentigines (NSML) as a related RASopathy, presenting primary with intractable neuropathic pain. We studied three unrelated adult patients with severe neuropathic pain and muscle weakness of the limbs. Nerve conduction studies and needle electromyography (EMG) were performed and PNS involvement was assessed by nerve ultrasound imaging, complemented with spinal magnetic resonance imaging (MRI) for the evaluation of proximal nerve segments. Targeted whole-exome sequencing analysis was performed when the diagnosis of NS was suspected. Two patients showed a PTPN11-related dominant and one a LZTR1-related recessive NS or NSML phenotype. The nature of PNS involvement was documented using nerve ultrasound and MRI, showing generalized or multifocal thickening of nerve roots, plexuses and peripheral nerves in all three patients. Nerve imaging using ultrasound and MRI aids in further detailing the nature of neuropathic pain and nerve hypertrophy in patients with NS. This study underlines the relevance of nerve ultrasound in neuropathies and pain syndromes. A NS diagnosis should not be overlooked in longstanding, unexplained neuropathic pain syndromes, with or without muscular weakness. Nerve ultrasound studies can help raise the suspicion for this relatively prevalent inherited multisystem disorder, which is still rather unknown among neurologists, particularly when other potential syndromic features are inconspicuous.

Visual versus quantitative analysis of muscle ultrasound in neuromuscular disease.

INTRODUCTION/AIMS: Visual and quantitative muscle ultrasound are both valid diagnostic tools in neuromuscular diseases. To optimize muscle ultrasound evaluation and facilitate its use in neuromuscular disease, we examined the correlation between visual and quantitative muscle ultrasound analysis and their pitfalls. METHODS: Retrospective data from 994 patients with 13,562 muscle ultrasound images were analyzed. Differences in echogenicity z-score distribution per Heckmatt grade and corresponding correlation coefficients were calculated. RESULTS: Overall, there was a correlation of 0.60 between the two scoring systems, with a gradual increase in z-score with increasing Heckmatt grades and vice versa. Patients with a neuromuscular disorder had higher Heckmatt grades (p < 0.001) and z-scores (median z-score = 0.30, p < 0.001) than patients without. The highest Heckmatt grades and z-scores were found in patients with either a dystrophy or inflammatory myopathy (both median Heckmatt grade of 2 and median z score of 0.74 and 1.20, respectively). Discrepant scores were infrequent (<2%), but revealed important pitfalls in both grading systems. DISCUSSION: Visual and quantitative muscle ultrasound are complementary techniques to evaluate neuromuscular disease and have a moderate positive correlation. Importantly, we identified specific pitfalls for visual and quantitative muscle ultrasound and how to overcome them in clinical practice.

Variability in electrodiagnostic findings associated with neurogenic thoracic outlet syndrome.

INTRODUCTION/AIMS: Neurogenic thoracic outlet syndrome (NTOS) is a heterogeneous and often disputed entity. An electrodiagnostic pattern of T1 > C8 axon involvement is considered characteristic for the diagnosis of NTOS. However, since the advent of high-resolution nerve ultrasound (US) imaging, we have encountered several patients with a proven entrapment of the lower brachial plexus who showed a different, variable electrodiagnostic pattern. METHODS: In this retrospective case series, 14 patients with an NTOS diagnosis with a verified source of compression of the lower brachial plexus and abnormal findings on their electrodiagnostic testing were included. Their medical records were reviewed to obtain clinical, imaging, and electrodiagnostic data. RESULTS: Seven patients showed results consistent with the "classic" T1 axon > C8 pattern of involvement. Less typical findings included equally severe involvement of T1 and C8 axons, more severe C8 involvement, pure motor abnormalities, neurogenic changes on needle electromyography in the flexor carpi radialis and biceps brachii muscles, and one patient with an abnormal sensory nerve action potential (SNAP) amplitude for the median sensory response recorded from the third digit. Patients with atypical findings on electrodiagnostic testing underwent nerve imaging more often compared to patients with classic findings (seven of seven patients vs. five of seven respectively), especially nerve ultrasound. DISCUSSION: When there is a clinical suspicion of NTOS, an electrodiagnostic finding other than the classic T1 > C8 pattern of involvement does not rule out the diagnosis. High resolution nerve imaging is valuable to diagnose additional patients with this treatable condition.

Imaging of neuralgic amyotrophy in the acute phase.

INTRODUCTION/AIMS: Hourglass-like constrictions (HGCs) occur in neuralgic amyotrophy (NA), but the earliest time at which they can be recognized by imaging is poorly understood. We aimed to determine the prevalence of abnormal imaging findings in the acute phase of NA. METHODS: Magnetic resonance neurography (MRN) and high-resolution ultrasound (US) examinations were performed at five sites. The investigation included 39 patients with acute NA who underwent imaging within 31 days of symptom onset. Correlation between imaging and electromyography (EMG) findings was measured. RESULTS: US was performed in 29 patients and MRN in 23; 16 patients underwent US only, 10 MRN only, and 13 had both. US and MRN showed nerve abnormalities within 1 mo from NA onset in 90% of patients. HGCs were found in 74% (29/39) of the patients: 4 within 1 wk, 8 within 2 wk, 5 within 3 wk, and 12 within 4 wk. The earliest HGC on US was found within 12 h, and on MRN within 3 days from symptom onset. MRN demonstrated a denervation edema pattern of affected muscles in 91% of the patients. The shortest time to observe an edema pattern on MRN was 8 days. EMG was performed in 30 patients and revealed fibrillation potentials in affected muscles in 22 (73%). A denervation edema pattern on MRN was significantly associated with the presence of HGCs both on MRN and US, and with fibrillation potentials on EMG. DISCUSSION: In the early phase of NA, US and MRN are useful diagnostic techniques for demonstrating nerve abnormalities.

Association of diaphragm thickness and echogenicity with age, sex, and body mass index in healthy subjects.

INTRODUCTION/AIMS: Diaphragm ultrasound is increasingly used in the diagnosis of diaphragm dysfunction and to guide respiratory management in patients with neuromuscular disorders and those who are critically ill. However, the association between diaphragm ultrasound variables and demographic factors like age, sex, and body mass index (BMI) are understudied. Such relationships are important for correct interpretation of normative values and comparison with selected patients groups. The aim of this study was to determine the associations between diaphragm ultrasound variables and subject characteristics. METHODS: B-mode ultrasound was used to image the diaphragm at the zone of apposition in 83 healthy subjects. Diaphragm thickness at resting end-expiration (Tend-exp ), diaphragm thickness at maximal end-inspiration (Tmax-insp ), diaphragm thickening ratio (Tmax-insp /Tend-exp ), and diaphragm echogenicity were measured. Multivariate linear regression was used to explore the associations between diaphragm ultrasound variables and subject characteristics. RESULTS: Tend-exp , Tmax-insp , and thickening ratio do not change with age whereas diaphragm echogenicity increases with age. The thickening ratio had a weak negative association with BMI, while Tend-exp was positively associated with BMI. Men had a larger Tend-exp and Tmax-insp than women (Tend-exp 1.6 ± 0.5 and 1.4 ± 0.3 mm; p = .011, Tmax-insp 3.8 ± 1.0 and 3.2 ± 0.9 mm; p = .004), but similar thickening ratios. DISCUSSION: Diaphragm thickness, thickening, and echogenicity measured with ultrasound are associated with factors such as age, BMI, and sex. Therefore, subject characteristics should be considered when interpreting diaphragm ultrasound measurements. In the absence of normative values, matched control groups are a prerequisite for research and in clinical practice.

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.