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.

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.

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.

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.

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.

Muscle ultrasound: Present state and future opportunities.

Muscle ultrasound is a valuable addition to the neuromuscular toolkit in both the clinic and research settings, with proven value and reliability. However, it is currently not fulfilling its full potential in the diagnostic care of patients with neuromuscular disease. This review highlights the possibilities and pitfalls of muscle ultrasound as a diagnostic tool and biomarker, and discusses challenges to its widespread implementation. We expect that limitations in visual image interpretation, posed by user inexperience, could be overcome with simpler scoring systems and the help of deep-learning algorithms. In addition, more information should be collected on the relation between specific neuromuscular disorders, disease stages, and expected ultrasound abnormalities, as this will enhance specificity of the technique and enable the use of muscle ultrasound as a biomarker. Quantified muscle ultrasound gives the most sensitive results but is hampered by the need for device-specific reference values. Efforts in creating dedicated muscle ultrasound systems and artificial intelligence to help with image interpretation are expected to improve usability. Finally, the standard inclusion of muscle and nerve ultrasound in neuromuscular teaching curricula and guidelines will facilitate further implementation in practice. Our hope is that this review will help in unleashing muscle ultrasound's full potential.

Diagnostic accuracy of gray scale muscle ultrasound screening for pediatric neuromuscular disease.

OBJECTIVE: Gray scale ultrasound (US) has been demonstrated to be a sensitive and specific tool in the diagnosis of pediatric neuromuscular disease (NMD). With recent advances in genetic testing, the diagnostic work up for NMD has evolved. The purpose of this study was to compare the current diagnostic value of gray scale US to previously defined sensitivities and specificities to determine when this test can add value to a patient's diagnostic workup. METHODS: Standardized quantitative gray scale US imaging was performed on 148 pediatric patients presenting for electrodiagnostic testing to evaluate for NMD. Patients were categorized as having an NMD, a non-NMD, or as "uncertain." The US results were defined as normal, borderline or abnormal based on echointensity values. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of the test were calculated. RESULTS: Forty-five percent of the patients had an NMD, 54% a non-NMD, and in 1% the diagnosis remained uncertain. US was abnormal in 73% of myopathies, 63% of neuromuscular junction disorders, 60% of generalized neuropathies and 58% of focal neuropathies. After excluding patients in whom muscle US was not expected to be abnormal (eg, sensory neuropathy), sensitivity was 83%, specificity 79%, PPV 75%, NPV 86%, and accuracy 81%. CONCLUSIONS: Quantitative gray scale muscle US still has good diagnostic value as a screening tool in pediatric NMD. As with any diagnostic test, muscle US is best used in conjunction with history and physical examination to increase specificity and diagnostic yield.

Need for prolonged immunosupressive therapy in CLIPPERS--a case report.

BACKGROUND: Chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (CLIPPERS) was first described in 2010 by Pittock and colleagues. All reported patients presented with diplopia and gait ataxia and had similar typical MRI findings with punctuate gadolinium enhancement of the pons. Alternative diagnoses were excluded by means of laboratory, radiological and histological tests. All patients were successfully treated with steroids. We present a case in which the steroid therapy was switched to long term immunosuppressive therapy, leading to several severe side-effects, but sustained clinical improvement. CASE PRESENTATION: A 63-year-old male presented with sub-acute diplopia and progressive gait ataxia. During admission his neurological condition worsened and he developed multiple cranial nerve deficits, paraparesis and urine retention. MRI-findings were remarkable with punctuate enhancement with gadolinium of the pons. Cerebrospinal fluid only showed elevated protein levels and all other additional investigations were normal. The probable diagnosis of CLIPPERS was made and intravenous corticosteroids were administered. This led to rapid clinical recovery and decreased enhancement on the MRI-scan. Long-term oral immunosuppressive therapy was started. One-and-a-half year later our patient has no recurrence of neurological symptoms, however due to the side effects of the immunosuppressive therapy he was readmitted several times. CONCLUSION: CLIPPERS presents with distinctive clinical and MRI-findings and may be diagnosed after excluding other differential diagnoses. Patients are treated with corticosteroids with good clinical results. Since short term glucocorticoid treatment results into relapse of the disease, longer term immunosuppressive therapy appears to be mandatory for sustained improvement, although accompanied by severe side effects.

Wrist Circumference-Dependent Upper Limit of Normal for the Cross-Sectional Area Is Superior Over a Fixed Cut-Off Value in Confirming the Clinical Diagnosis of Carpal Tunnel Syndrome.

Introduction: In confirming the clinical diagnosis of carpal tunnel syndrome (CTS), ultrasonography (US) is the recommended first diagnostic test in The Netherlands. One of the most important parameters for an abnormal US result is an increase of the CSA of the median nerve at the carpal tunnel inlet. An earlier study showed that a wrist-circumference dependent cut-off for the upper limit of normal of this CSA might be superior to a fixed cut-off of 11 mm2. In this study we compared three ultrasonography (US) parameters in three large Dutch hospitals. Methods: Patients with a clinical suspicion of CTS and with reasonable exclusion of other causes of their symptoms were prospectively included. A total number of 175 patients were analysed. The primary goal was to compare the number of wrists with an abnormal US result while using a fixed cut-off of 11 mm2 (FC), a wrist circumference-dependent cut-off (y = 0.88 * x-4, where y = ULN and x = wrist circumference in centimetres; abbreviated as WDC), and an intraneural flow related cut-off (IFC). Results: The WDC considered more US examinations to be abnormal (55.4%) than the FC (50.3%) did, as well as the IFC (46.9%), with a statistically significant difference of p = 0.035 and p = 0.001, respectively. The WDC detected 12 abnormal median nerves while the FC did not, and 18 while the IFC did not. The wrist circumference of the patients of these subgroups turned out to be significantly smaller (p < 0.001) when compared with the rest of the group. Conclusion: According to these study results, the wrist-circumference dependent cut-off value for the CSA of the median nerve at the wrist appears to have a higher sensitivity than either a fixed cut-off value of 11 mm2 or cut-off values based on intraneural flow, and may add most value in patients with a smaller wrist circumference.

Nerve Ultrasound in Traumatic and Iatrogenic Peripheral Nerve Injury.

Peripheral nerve injury is a potentially debilitating disorder that occurs in an estimated 2-3% of all patients with major trauma, in a similar percentage of medical procedures. The workup of these injuries has traditionally been clinical, combined with electrodiagnostic testing. However, this has limitations, especially in the acute phase of the trauma or lack of any recovery, when it is very important to determine nerve continuity and perform surgical exploration and repair in the case of the complete transection or intraneural fibrosis. Ultrasound can help in those situations. It is a versatile imaging technique with a high sensitivity of 93% for detecting focal nerve lesions. Ultrasound can assess the structural integrity of the nerve, neuroma formation and other surrounding abnormalities of bone or foreign bodies impeding the nerve. In addition, this can help to prevent iatrogenic nerve injury by marking the nerve before the procedure. This narrative review gives an overview of why and how nerve ultrasound can play a role in the detection, management and prevention of peripheral nerve injury.

Computer-aided detection of fasciculations and other movements in muscle with ultrasound: Development and clinical application.

OBJECTIVE: To develop an automated algorithm for detecting fasciculations and other movements in muscle ultrasound videos. Fasciculation detection in muscle ultrasound is routinely performed online by observing the live videos. However, human observation limits the objective information gained. Automated detection of movement is expected to improved sensitivity and specificity and increase reliability. METHODS: We used 42 ultrasound videos from 11 neuromuscular patients for an iterative learning process between human observers and automated computer analysis, to identify muscle ultrasound movements. Two different datasets were selected from this, one to develop the algorithm and one to validate it. The outcome was compared to manual movement identification by clinicians. The algorithm also quantifies specific parameters of different movement types, to enable automated differentiation of events. RESULTS: The algorithm reliably detected fasciculations. With algorithm guidance, observers found more fasciculations compared to visual analysis alone, and prescreening the videos with the algorithm saved clinicians significant time compared to reviewing full video sequences. All videos also contained other movements, especially contraction pseudotremor, which confused human interpretation in some. CONCLUSIONS: Automated movement detection is a feasible and attractive method to screen for fasciculations in muscle ultrasound videos. SIGNIFICANCE: Our findings affirm the potential clinical usefulness of automated movement analysis in muscle ultrasound.

Normative values of semitendinosus tendon reflex latencies.

OBJECTIVES: The semitendinosus tendon reflex (STR), also known as the medial hamstring reflex, is rarely described in literature and is believed to provide information mainly concerning the fifth lumbar spinal nerve (L5). Latencies can be obtained with clinical neurophysiological tests. Normative data for STR latencies are not available. The aim of this study was to provide normative values of STR latencies. Also we will describe the technique used for performing the tendon reflex measurements in a clinical neurophysiological setting. METHODS: To determine STR latencies, we measured the stimulus (tap with reflex hammer) - response (EMG activity associated with muscle contraction) relation. The stimulus was administered with a manually operated reflex hammer, tipped with electrically conductive rubber, triggering the EMG recording sweep on impact. The EMG response was recorded with surface electrodes placed on the skin overlying the semitendinosus muscle. RESULTS: Forty healthy subjects participated in the study. The group consisted of 18 women and 22 men with a median age of 30 years. The mean subject body height was 181 cm (SD 8.1). Latencies showed a significant correlation with body height (r = 0.70, R2 = 0.48, P < 0.0001). The mean latency of the STR was 24.73 ms (SD 1.96). The rounded upper limit of normal of individual absolute right-left differences was 2 ms. CONCLUSION: We present, as far as we know, the first report on normative values of STR latencies. The STR could be elicited in 100% of our population. The left-right difference seems to be the most promising clinical parameter for diagnostic purposes. SIGNIFICANCE: We think our results can be of practical use for all clinical neurophysiologists/neurologists and may provide the basis for further research on test characteristics of STR latencies in patients with L5 radiculopathy.

Severe isolated sciatic neuropathy due to a modified lotus position.

A 51-year-old man presented to our hospital with progressive pain and weakness in his right leg. Neurological examination revealed atrophy of all muscles of the right leg, unilateral foot drop and paralysis of the anterior tibial and gastrocnemicus muscles. Electromyography confirmed a severe isolated sciatic neuropathy in the thigh. For unclear reasons, our patient habitually used to sit in a modified lotus position. We concluded that this position, in literature known as "lotus neuropathy" had resulted in the sciatic neuropathy. After more than a year our patient was referred again to our outpatient clinic. At that time there was only minimal improvement, now with an achilles tendon contracture and pes equinus due to immobility.