Ultrasonography of MADSAM neuropathy: focal nerve enlargements at sites of existing and resolved conduction blocks

Neuromuscular Ultrasound in Polyneuropathies

Neuromuscular ultrasound is a painless, radiation-free, high-resolution imaging technique for assessing the peripheral nervous system. It can accurately depict changes in the nerves and muscles of individuals with neuromuscular conditions, and it is therefore a robust diagnostic tool for the assessment of individuals with polyneuropathies. This review will outline the typical ultrasonographic changes found in a wide variety of polyneuropathies. In general, demyelinating conditions result in greater nerve enlargement than axonal conditions, and acquired conditions result in more patchy nerve enlargement compared to diffuse nerve enlargement in hereditary conditions. This review is data-driven, but more nuanced anecdotal findings are also described. The overall goal of this paper is to provide clinicians with an accessible review of the ultrasonographic approaches and findings in a wide variety of polyneuropathies.

The distribution pattern of nerve enlargement in clinical subtypes of chronic inflammatory demyelinating polyneuropathy

BACKGROUND AND PURPOSE

We aim to investigate nerve enlargement patterns and their correlation with clinical subtypes and treatment response using nerve ultrasound in chronic inflammatory demyelinating polyradiculoneuropathy (CIDP).

METHODS

Between March 2015 and December 2021, 135 CIDP patients were recruited. Nerve ultrasound and electrophysiological studies were performed on the median and ulnar nerves. The responses to intravenous immunoglobulin (IVIg) or prednisone were evaluated with the disability score.

RESULTS

There were 99 typical CIDP cases, 10 Lewis-Sumner syndrome (LSS) cases, 15 distal acquired demyelinating symmetric neuropathy (DADS) cases, nine pure motor CIDP cases, and two pure sensory CIDP cases. Sixty (61%) typical CIDP and seven (78%) pure motor CIDP patients had moderately increased or normal cross-sectional area (CSA), and 10 (67%) DADS and seven (70%) LSS patients had significantly increased CSA. The peripheral nerve showed a diffuse enlargement pattern in 46 (51%) typical CIDP, five (50%) LSS, three (25%) DADS, and three (33%) pure motor CIDP patients and a proximal regional enlargement pattern in 11 (12%) typical CIDP, one (10%) LSS, six (50%) DADS, and four (44%) pure motor CIDP patients. Patients with diffusely moderate enlargement patterns and those with proximal regional enlargement showed a higher response rate to glucocorticoids than to IVIg.

CONCLUSIONS

Various distribution patterns of nerve enlargement existed in CIDP. Although almost all patterns could be detected in each CIDP subtype, diffusely moderate enlargement was more common in typical CIDP and LSS, while proximal regional enlargement was more common in DADS and pure motor CIDP. Different enlargement patterns might indicate different treatment responses.

Cross-sectional area reference values for high-resolution ultrasonography of the lower extremity nerves in healthy Korean adults

The cross-sectional area (CSA) reference values of the lower extremity nerves in Asians have been rarely reported. For this study, 107 sex- and age-matched, healthy subjects with a mean age of 46 years (range, 24-75 years) were recruited. All subjects underwent standardized nerve conduction studies of the upper and lower extremities. The CSA was measured unilaterally at 12 sites in the lower extremity nerves, including the femoral, lateral femoral cutaneous, sciatic, common peroneal, superficial peroneal, deep peroneal, tibial, and sural nerves. The CSA significantly correlated with height, weight, and body mass index. The CSA was significantly larger in males than females at most nerves except for the lateral femoral cutaneous, common peroneal (fibular head), and superficial peroneal nerves (distal calf). There was no statistically significant difference between the age groups except for the tibial nerve (ankle). The results of this study provide CSA reference values for the lower extremity nerves including small branches and the values can be useful in the ultrasonographic investigation of various peripheral neuropathies in East Asian populations.

Application and Research Progress of High Frequency Ultrasound in the Diagnosis of Chronic Inflammatory Neuropathies

In recent years, clinicians have gradually improved their understanding of multiple neuropathy and have done some studies about chronic inflammatory neuropathies, for example, chronic inflammatory demyelinating polyneuropathy, multifocal motor neuropathy, and Lewis-Sumne syndrome. The early diagnosis is very important for the next step treatment and long-term prognosis. At present, the disease mainly depends on clinical and neural electrophysiological examination, but imaging studies are few. In recent years, with the rapid development of high frequency ultrasound, it could clearly show the morphology of the nerve, and it has been an emerging diagnosis tool of polyneuropathies. This article mainly reviews the application and the latest research progress of high frequency ultrasound in these diseases.

Acute to Subacute Atraumatic Entrapment Neuropathies in Patients With CMT1A: A Report of a Distinct Phenotypic Variant of CMT1A

Charcot-Marie-Tooth type 1A (CMT1A) is typically characterised as a childhood-onset, symmetrical, length-dependent polyneuropathy with a gradual progressive clinical course. Acute to subacute neurological deterioration in CMT1A is rare, and has been reported secondary to overlap pathologies including inflammatory neuropathy. We identified two patients with CMT1A who presented with acute to subacute, atraumatic, entrapment neuropathies as an initial symptom. A superimposed inflammatory neuropathy was excluded. Both patients had a diffuse demyelinating polyneuropathy, with markedly low motor nerve conduction velocities (<20 m/s). In both patients, we demonstrated symptomatic and asymptomatic partial conduction blocks at multiple entrapment sites. Nerve ultrasound findings in our patients demonstrated marked diffuse nerve enlargement, more pronounced at non-entrapment sites compared to entrapment sites. We discuss ways to distinguish this condition from its other differentials. We propose pathophysiological mechanisms underlying this condition. We propose that CMT1A with acute to subacute, atraumatic, entrapment neuropathies to be a distinct phenotypic variant of CMT1A.

Bilateral widespread segmental swelling on nerve sonography in multifocal acquired demyelinating sensory and motor neuropathy: Two case reports

INTRODUCTION

Multifocal acquired demyelinating sensory and motor neuropathy (MADSAM) is an asymmetric immune-related neuropathy with conduction block. We report 2 MADSAM cases with detailed clinical, electrophysiological, and sonography profiles.

PATIENT CONCERNS AND DIAGNOSIS

Two cases presented with patchy sensorimotor impairment in both clinical and electrophysiological findings. Notably, nerve ultrasound demonstrated multifocal nerve enlargement not only at sites of conduction blockade but also at the unaffected contralateral sites. Interestingly, in our first case, focal radial nerve enlargement was observed prior to the clinical manifestations, suggesting nerve dynamic pathogenesis with variable clinical significance.

INTERVENTIONS AND OUTCOMES

The first patient was initially treated with prednisolone, however, 3 months after steroid therapy, her symptoms progressed. After treatment with intravenous immunoglobulin for 3 months, the symptoms stabilized. The second patient showed improvement after 2 months of prednisolone treatment.

CONCLUSION

These observations suggest a more widespread pathomechanism underlying MADSAM, and ultrasound may detect nerve lesions earlier than clinical electrophysiology studies, and is warranted for early detection and thorough documentation of nerve pathology.

Sonographic Multifocal Cranial Nerve Enlargement in Multifocal Acquired Demyelinating Sensory and Motor Neuropathy

Multifocal enlargements with the alteration of a normal fascicular pattern are considered to be sonographic peripheral nerve features in multifocal acquired demyelinating sensory and motor neuropathy (MADSAM), a subtype of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). We herein present the case of an 18-year-old patient with MADSAM in whom intensive sonological assessments revealed multifocal nerve enlargement within clinically affected cranial nerves. Our case demonstrated that, if systematically investigated with ultrasound, morphological changes similar to those in the peripheral nerves may be detected in a large proportion of clinically affected cranial nerves in MADSAM, boosting the future applications of cranial nerve ultrasound in CIDP.

Review Article "Spotlight on Ultrasonography in the Diagnosis of Peripheral Nerve Disease: The Evidence to Date"

Neuromuscular ultrasound is rapidly becoming incorporated into clinical practice as a standard tool in the assessment of peripheral nerve diseases. Ultrasound complements clinical phenotyping and electrodiagnostic evaluation, providing critical structural anatomical information to enhance diagnosis and identify structural pathology. This review article examines the evidence supporting neuromuscular ultrasound in the diagnosis of compressive mononeuropathies, traumatic nerve injury, generalised peripheral neuropathy and motor neuron disease. Extending the sonographic evaluation of nerves beyond simple morphological measurements has the potential to improve diagnostics in peripheral neuropathy, as well as advancing the understanding of pathological mechanisms, which in turn will promote precise therapies and improve therapeutic outcomes.

Nerve ultrasound findings in Sjögren's syndrome-associated neuropathy

BACKGROUND AND PURPOSE

The phenotype of Sjögren's syndrome-associated neuropathy has been better characterized in recent years. However, Sjögren's syndrome-associated neuropathy remains an underdiagnosed entity with only few insights considering the pathomechanisms of nerve damage. Nerve ultrasound has proven to be a useful and efficient tool in detecting nerve damage of autoimmune origin. We, therefore, aimed to evaluate this method for Sjögren's syndrome-associated neuropathy.

METHODS

Patients with Sjögren's syndrome and clinical signs of neuropathy underwent sonographic examination of both median and ulnar nerves. Nerve thickening was classified for cross-sectional areas of >12 mm² at the median nerve and for >10 mm² at the ulnar nerve. Fascicle thickening was documented for cross-sectional areas ≥5 mm² at the median and ≥3 mm² at the ulnar nerve.

RESULTS

Forty-three patients were included in the analysis (median age 60 years [interquartile range 53-73 years], female rate 60%). 31/43 patients (72%) showed abnormalities on nerve ultrasound, while nerve thickening was found more frequently than fascicle thickening (90% vs. 52% of patients with sonographic abnormalities, respectively). Abnormal findings were observed more frequently at the median nerve and in proximal localization. Abnormal findings on nerve conduction studies were evident in 36/43 patients (84%). Nerve conduction studies revealed a tendency of demyelinating nerve damage patterns being associated with abnormal findings on nerve ultrasound.

CONCLUSIONS

In addition to nerve conduction studies, nerve ultrasound may have a supporting role in the diagnosis of Sjögren's syndrome-associated neuropathy. Also, our data support an immune-mediated inflammatory demyelinating pathogenesis of Sjögren's syndrome-associated neuropathy.

Multifocal acquired demyelinating sensory and motor neuropathy misdiagnosed as carpal tunnel syndrome: a case report

Multifocal acquired demyelinating sensory and motor neuropathy (MADSAM), a subtype of chronic inflammatory demyelinating polyneuropathy, is a non-compressive peripheral nerve disorder. Symptoms of MADSAM include asymmetrical weakness and sensory deficits in the distribution of individual peripheral nerves, which are frequently noted in the distal portion of peripheral nerves. MADSAM can be easily misdiagnosed as any of the various compressive peripheral neuropathies. Here, we present a case of MADSAM misdiagnosed as carpal tunnel syndrome (CTS). A 53-year-old woman had bilateral asymmetrical hand weakness (left hand: significant weakness, right hand: slight motor weakness) and a slight weakness of her bilateral lower extremities. Sensory deficit was found on the volar side of her left hand. She had visited many clinics previously and was diagnosed with CTS. However, an electrodiagnostic study performed in our hospital did not identify CTS but indicated a demyelinating peripheral neuropathy in all limbs. On the basis of the patient’s clinical symptoms and laboratory findings, she was diagnosed with MADSAM. When patients exhibit progressive aggravating motor weakness and sensory deficits in more than one distal limb without a specific finding of compressive neuropathy in electrodiagnostic studies, clinicians should consider the possibility of MADSAM.

Cross-sectional area reference values for high-resolution ultrasonography of the upper extremity nerves in healthy Asian adults

In this study, multiple-site, cross-sectional area (CSA) reference values were established for major peripheral nerves, including small branches, in the upper extremity of a healthy Asian population.This study included 107 prospectively recruited age-matched, healthy subjects with a mean age of 46 years (range, 24-75 years). All subjects underwent standardized nerve conduction studies for the median, ulnar, peroneal, posterior tibial, and sural nerves. CSA was measured unilaterally at 21 sites of the median, ulnar, radial, posterior interosseous, superficial radial sensory, musculocutaneous, lateral antebrachial cutaneous, and medial antebrachial cutaneous nerves.According to their age, the subjects were assigned to the younger group (20-40 years, n = 40), the middle group (40-59 years, n = 40), and the older group (60-80 years, n = 27). The significant differences of CSA values between age groups were found only at certain sites, such as the median (wrist, P = .003), ulnar (medial epicondyle, P = .031; forearm, P = .022), radial (antecubital fossa, P = .037), and superficial radial sensory nerve (P = .028). The CSA significantly correlated with gender, height, weight, and body mass index.This study provides CSA reference values for nerves, including small sensory nerves in the upper extremity, which can be useful in the ultrasonographic investigation of various peripheral neuropathies in the upper extremity.

Sonographic Nerve Enlargement in a Patient with Sarcoidosis

We herein report a 73-year-old woman case with sarcoid neuropathy showing nerve enlargement assessed by nerve ultrasound both before and after treatment. The site of conduction block in the left tibial nerve corresponded to the site of nerve enlargement with a hypo-echoic pattern. After treatment with prednisolone, nerve ultrasound detected the remission of the nerve enlargement, and the conduction block and clinical symptoms also improved. Nerve enlargement may reflect inflammation of the peripheral nerve. A follow-up study of sonographic nerve enlargement may be of clinical significance for assessing the effectiveness of treatment for sarcoid neuropathy.

Nerve Ultrasound as Helpful Tool in Polyneuropathies

Background: Polyneuropathies (PNP) are a broad field of diseases affecting millions of people. While the symptoms presented are mostly similar, underlying causes are abundant. Thus, early identification of treatable causes is often difficult. Besides clinical data and basic laboratory findings, nerve conduction studies are crucial for etiological classification, yet limited. Besides Magnetic Resonance Imaging (MRI), high-resolution nerve ultrasound (HRUS) has become a noninvasive, fast, economic and available tool to help distinguish different types of nerve alterations in neuropathies. Methods: We aim to describe typical ultrasound findings in PNP and patterns of morphological changes in hereditary, immune-mediated, diabetic, metabolic and neurodegenerative PNP. Literature research was performed in PubMed using the terms ‘nerve ultrasound’, neuromuscular ultrasound, high-resolution nerve ultrasound, peripheral nerves, nerve enlargement, demyelinating, hereditary, polyneuropathies, hypertrophy’. Results: Plenty of studies over the past 20 years investigated the value of nerve ultrasound in different neuropathies. Next to nerve enlargement, patterns of nerve enlargement, echointensity, vascularization and elastography have been evaluated for diagnostic terms. Furthermore, different scores have been developed to distinguish different etiologies of PNP. Conclusions: Where morphological alterations of the nerves reflect underlying pathologies, early nerve ultrasound might enable a timely start of available treatment and also facilitate follow up of therapy success.

Comprehensive approaches for diagnosis, monitoring and treatment of chronic inflammatory demyelinating polyneuropathy

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is the most common chronic inflammatory neuropathy. CIDP is diagnosed according to the European Federation of Neurological Societies/Peripheral Nerve Society (EFNS/PNS) criteria, which combine clinical features with the electrophysiological evidence of demyelination. However, firstly, diagnosis is challenging, as some patients e.g. with severe early axonal damage do not fulfil the criteria. Secondly, objective and reliable tools to monitor the disease course are lacking. Thirdly, about 25% of CIDP patients do not respond to evidence-based first-line therapy. Recognition of these patients is difficult and treatment beyond first-line therapy is based on observational studies and case series only. Individualized immunomodulatory treatment does not exist due to the lack of understanding of essential aspects of the underlying pathophysiology.

Novel diagnostic imaging techniques and molecular approaches can help to solve these problems but do not find enough implementation. This review gives a comprehensive overview of novel diagnostic techniques and monitoring approaches for CIDP and how these can lead to individualized treatment and better understanding of pathophysiology.

Use of Magnetic Resonance Neurography for Evaluating the Distribution and Patterns of Chronic Inflammatory Demyelinating Polyneuropathy

Objective

To evaluate the distribution and characteristics of peripheral nerve abnormalities in chronic inflammatory demyelinating polyneuropathy (CIDP) using magnetic resonance neurography (MRN) and to examine the diagnostic efficiency.

Materials and Methods

Thirty-one CIDP patients and 21 controls underwent MR scans. Three-dimensional sampling perfections with application-optimized contrasts using different flip-angle evolutions and T1-/T2- weighted turbo spin-echo sequences were performed for neurography of the brachial and lumbosacral (LS) plexus and cauda equina, respectively. Clinical data and scores of the inflammatory Rasch-built overall disability scale (I-RODS) in CIDP were obtained.

Results

The bilateral extracranial vagus (n = 11), trigeminal (n = 12), and intercostal nerves (n = 10) were hypertrophic. Plexus hypertrophies were observed in the brachial plexus of 19 patients (61.3%) and in the LS plexus of 25 patients (80.6%). Patterns of hypertrophy included uniform hypertrophy (17 [54.8%] brachial plexuses and 21 [67.7%] LS plexuses), and multifocal fusiform hypertrophy (2 [6.5%] brachial plexuses and 4 [12.9%] LS plexuses) was present. Enlarged and/or contrast-enhanced cauda equina was found in 3 (9.7%) and 13 (41.9%) patients, respectively. Diameters of the brachial and LS nerve roots were significantly larger in CIDP than in controls (p < 0.001). The largest AUC was obtained for the L5 nerve. There were no significant differences in the course duration, I-RODS score, or diameter between patients with and without hypertrophy.

Conclusion

MRN is useful for the assessment of distribution and characteristics of the peripheral nerves in CIDP. Compared to other regions, LS plexus neurography is more sensitive for CIDP.

Current and future applications of ultrasound imaging in peripheral nerve disorders

Neuromuscular ultrasound (NMUS) is a rapidly evolving technique used in neuromuscular medicine to provide complimentary information to standard electrodiagnostic studies. NMUS provides a dynamic, real time assessment of anatomy which can alter both diagnostic and management pathways in peripheral nerve disorders. This review describes the current and future techniques used in NMUS and details the applications and developments in the diagnosis and monitoring of compressive, hereditary, immune-mediated and axonal peripheral nerve disorders, and motor neuron diseases. Technological advances have allowed the increased utilisation of ultrasound for management of peripheral nerve disorders; however, several practical considerations need to be taken into account to facilitate the widespread uptake of this technique.

Neuromuscular ultrasound in clinical practice: A review

Neuromuscular ultrasound (NMUS) is becoming a standard element in the evaluation of peripheral nerve and muscle disease. When obtained simultaneously to electrodiagnostic studies, it provides dynamic, structural information that can refine a diagnosis or identify a structural etiology. NMUS can improve patient care for those with mononeuropathies, polyneuropathy, motor neuron disease and muscle disorders. In this article, we present a practical guide to the basics of NMUS and its clinical application. Basic ultrasound physics, scanning techniques and clinical applications are reviewed, along with current challenges.

Multimodal magnetic resonance imaging of peripheral nerves: Establishment and validation of brachial and lumbosacral plexi measurements in 163 healthy subjects

PURPOSE

This study aims to provide normal reference values for quantitative parameters for brachial and lumbosacral plexi on multimodal MRI. In addition, the parameter variations between the left and right sides, the individual nerve groups, genders and age groups were also evaluated.

MATERIALS AND METHODS

Multimodal MRI was evaluated in 163 healthy subjects, who were randomly divided into three groups: brachial plexus, lumbosacral plexus and diffusion tensor imaging groups. Nerve diameters, contrast ratios, T2 nerve-muscle signal ratios (nT2), fractional anisotropy (FA) values and apparent diffusion coefficients (ADC) were measured in both plexi. Parametric tests and Pearson correlation for normally distributed data, and non-parametric tests and Spearman correlation for non-normally distributed data were used.

RESULTS

There were no significant differences in parameters between the left and right sides. The diameters of the C7, L4-S1, sciatic, and femoral nerve roots were larger in men than in women (P < 0.05). The nT2 in the brachial and lumbosacral plexi and the contrast ratio in the lumbosacral plexus were significantly higher in the elderly. The diameter of the S1 nerve root was smaller in the elderly. There were no significant differences between the individual nerve groups in contrast ratios and in brachial plexus nT2. A gradual increase in the nT2 from the top to the bottom was observed in the L4-S1 nerve roots (P < 0.05).

CONCLUSION

This study provides multi-parameter normative data for the brachial and lumbosacral plexi while considering differences between the two sides, the individual nerves, genders, and the ages.

Nerve ultrasound in polyneuropathies

Ultrasound can be used to visualize pathology in the peripheral nerves of patients with polyneuropathy. Nerve enlargement is the most frequent pathology, but other abnormalities, including abnormal nerve echogenicity and vascularity, are also encountered. This monograph presents an overview of the role of nerve ultrasound in the evaluation and management of both inherited and acquired polyneuropathies. A description of the sonographic techniques and common abnormalities is provided, followed by a presentation of typical findings in different neuropathies. Scoring systems for characterizing the presence and pattern of nerve abnormalities as they relate to different polyneuropathies are presented. Muscle Nerve 57: 716-728, 2018.

A look inside the nerve - Morphology of nerve fascicles in healthy controls and patients with polyneuropathy

OBJECTIVE

Polyneuropathies are increasingly analyzed by ultrasound. Summarizing, diffuse enlargement is typical in Charcot-Marie Tooth type 1 (CMT1a), regional enlargement occurs in inflammatory neuropathies. However, a distinction of subtypes is still challenging. Therefore, this study focused on fascicle size and pattern in controls and distinct neuropathies.

METHODS

Cross-sectional area (CSA) of the median, ulnar and peroneal nerve (MN, UN, PN) was measured at predefined landmarks in 50 healthy controls, 15 CMT1a and 13 MMN patients. Additionally, largest fascicle size and number of visible fascicles was obtained at the mid-upper arm cross-section of the MN and UN and in the popliteal fossa cross-section of the PN.

RESULTS

Cut-off normal values for fascicle size in the MN, UN and PN were defined (<4.8mm², <2.8mm² and <3.5mm²). In CMT1a CSA and fascicle values are significantly enlarged in all nerves, while in MMN CSA and fascicles are regionally enlarged with predominance in the upper arm nerves. The ratio of enlarged fascicles and all fascicles was significantly increased in CMT1a (>50%) in all nerves (p<0.0001), representing diffuse fascicle enlargement, and moderately increased in MMN (>20%), representing differential fascicle enlargement (enlarged and normal fascicles at the same location) sparing the peroneal nerve (regional fascicle enlargement). Based on these findings distinct fascicle patterns were defined.

CONCLUSION

Normal values for fascicle size could be evaluated; while CMT1a features diffuse fascicle enlargement, MMN shows regional and differential predominance with enlarged fascicles as single pathology.

SIGNIFICANCE

Pattern analysis of fascicles might facilitate distinction of several otherwise similar neuropathies.

Giant nerves in chronic inflammatory polyradiculoneuropathy

INTRODUCTION

Nerve enlargement (NE) is described in inflammatory and inherited neuropathies. It is commonly multifocal and moderate in the former and homogeneous and generalized in the latter. We describe 4 cases of massive NE in inflammatory neuropathies.

METHODS

Patients presented with symptoms of polyneuropathy that progressed over months to years. Nerve conduction studies (NCS), laboratory analysis, nerve MRI, and nerve ultrasound were performed.

RESULTS

NCS revealed demyelinating neuropathy in all with multifocal conduction blocks or increased terminal latency indices. MRI/ultrasound revealed extensive NE in the roots and nerves. Detailed diagnostics including biopsies, positron emission tomography-computed tomography, and genetic testing revealed no other pathology. Chronic inflammatory demyelinating polyneuropathy variants were diagnosed in all, and immunotherapies were successfully initiated.

CONCLUSIONS

MRI and ultrasound contributed to diagnosis and therapy. All patients had giant NE in common, which strongly suggested inherited neuropathy. However, the final diagnosis was inflammatory neuropathy. Impressive NE can occur in immune-mediated neuropathies and should be carefully differentiated from inherited neuropathies. Muscle Nerve 55: 285-289, 2017.

Normalization of sonographical multifocal nerve enlargements in a MADSAM patient following a good clinical response to intravenous immunoglobulin

Focal nerve enlargements at sites of conduction blocks can be visualized sonographically in patients with multifocal acquired demyelinating sensory and motor neuropathy (MADSAM). However, little is known about association between nerve morphological changes and treatment responses. Here we present a 73-year-old female MADSAM patient whose sonographical multifocal nerve enlargements normalized following a good treatment response. She was admitted to our department with progressive asymmetrical muscle weakness and sensory disturbances for 6 months. Ultrasonography revealed multifocal nerve enlargements at sites of electrophysiological demyelination. Intravenous immunoglobulin improved her symptoms and electrophysiological abnormalities. Six months later, ultrasonography revealed normalization of multifocal nerve enlargements. Contrary to our observations, one previous report described a MADSAM patient with persistent nerve enlargements at the sites of resolved conduction blocks. In this earlier patient, however, the time from onset to remission was approximately 30 months. Morphological changes of nerve enlargements in MADSAM may vary with treatment response.

Intraoperative high-resolution ultrasound and contrast-enhanced ultrasound of peripheral nerve tumors and tumorlike lesions

The diagnostic workup and surgical therapy for peripheral nerve tumors and tumorlike lesions are challenging. Magnetic resonance imaging is the standard diagnostic tool in the preoperative workup. However, even with advanced pulse sequences such as diffusion tensor imaging for MR neurography, the ability to differentiate tumor entities based on histological features remains limited. In particular, rare tumor entities different from schwannomas and neurofibromas are difficult to anticipate before surgical exploration and histological confirmation. High-resolution ultrasound (HRU) has become another important tool in the preoperative evaluation of peripheral nerves. Ongoing software and technical developments with transducers of up to 17-18 MHz enable high spatial resolution with tissue-differentiating properties. Unfortunately, high-frequency ultrasound provides low tissue penetration. The authors developed a setting in which intraoperative HRU was used and in which the direct sterile contact between the ultrasound transducer and the surgically exposed nerve pathology was enabled to increase structural resolution and contrast. In a case-guided fashion, the authors report the sonographic characteristics of rare tumor entities shown by intraoperative HRU and contrast-enhanced ultrasound.

Ultrasound pattern sum score, homogeneity score and regional nerve enlargement index for differentiation of demyelinating inflammatory and hereditary neuropathies

OBJECTIVE

To investigate the use of nerve ultrasound in the differentiation between Charcot-Marie Tooth hereditary neuropathy (CMT1) and chronic inflammatory demyelinating polyradiculoneuropathies (CIDP), multifocal motor neuropathy (MMN) and multifocal acquired demyelinating sensory and motor neuropathies (MADSAM).

METHODS

Ultrasound/electrophysiology of predefined nerves was performed in CMT1a/b, immunoneuropathies, and healthy controls. Ultrasound pattern sum score (UPSS, sum of the amount of 12 predefined measurement points), homogeneity score (HS) and regional nerve enlargement index (RNEI) in ulnar, median, and tibial nerve were used for evaluation of morphology.

RESULTS

13 CMT1, 27 CIDP, 10 MADSAM, 12 MMN, and 23 controls were included. Significant enlargement was shown in all neuropathies compared to the controls, (p<0.001), however the amount of enlargement as evaluated by the UPSS was most prominent in CMT compared to the others (median UPSS 18 vs. 11/8.5/5 in CIDP/MADSAM/MMN, p<0.001). Homogeneous enlargement was significantly more often seen in CMT (67%, HS 6 vs. 2-3 in immune-mediated PNP, p<0.001), while in CIDP the enlargement was regional, homogeneous or inhomogeneous with equal contribution. In MMN and MADSAM regional enlargement (48%/40%) next to normal segments (∼20%) predominated (RNEI in MMN=2, in MADSAM=1 vs. 0 in the others). CSAs were inversely correlated with motor conduction velocity.

CONCLUSION

Ultrasound, quantified by UPSS, HS, and RNEI facilitates a reliable and reproducible differentiation of immunoneuropathies and hereditary neuropathies by the use of boundary values.

SIGNIFICANCE

By the use of quantitative scores, ultrasound differentiation of demyelinating neuropathies is operationalized and ameliorated compared to CSA measurements only.

Ultrasound aspects in therapy-naive CIDP compared to long-term treated CIDP

To investigate the use of nerve ultrasound (NUS) along with the European Federation of Neurological Societies (EFNS) guidelines and clinical scores in untreated, recently diagnosed chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) vs. long-lasting treated CIDP. NUS and nerve conduction studies (NCS) of predefined nerves/cervical roots were performed in CIDP on diagnostic onset and "chronic-CIDP" (diagnosis and therapy >6 months), compared to controls. Nerve morphology was quantified using the modified ultrasound pattern sum score mUPSS, which is the sum of 3 ultrasound scores derived at 12 predefined measurement points and the homogeneity score (HS) in ulnar, median, and tibial nerve. 21 onset-CIDP, 21 "chronic-CIDP", and 21 age-matched controls were included. No differences in clinical scores or in the number of electrophysiologically affected nerves existed between the groups. Significantly enlarged cross-sectional areas of the nerves and diameters of the roots ensued already in onset-CIDP; however, with proximal predominance, whilst in chronic-CIDP, nerve enlargement was more prominent and ubiquitous. Increased UPS scores were shown in both patient groups compared to the controls. Significant differences between the patient groups were found particularly in the peripheral nerve score UPSA. Evaluation by means of HS revealed that the nerves in onset-CIDP were mostly regionally enlarged (often sparing distal segments) whereas in chronic-CIDP, nerves were more generalized enlarged. Onset- and chronic-CIDP show enlarged nerves and therefore increased mUPSS, however, nerve enlargement shows a more generalized pattern in chronic-CIDP compared to disease onset and correlates with disease duration and delayed therapy start, but not with disability.

Ultrasonography of the peripheral nervous system in the early stage of Guillain-Barré syndrome

Ultrasonography can be used to visualize peripheral nerve abnormalities in immune-mediated neuropathies. The objective of this study was to prove the role of ultrasonography (US) in acute phase of Guillain-Barré syndrome (GBS). Systematic ultrasonic measurements of several peripheral nerves including the vagal nerve as well as the sixth cervical nerve root were performed in 18 patients with GBS at days 1-3 after symptom onset and compared to 21 healthy controls. Nerve conduction studies (NCS) of corresponding nerves were undertaken. Consequently, significant differences between the groups were found in compound muscle action potential amplitudes, F-wave latency, and persistency. Ultrasonic cross-sectional areas (CSAs) showed significant enlargement in all nerves except of the ulnar nerve (upper arm) and the sural nerve compared to healthy controls, most prominent in proximal and middle median nerve (p < 0.01). The vagal nerve also showed enlargement compared to controls (p < 0.05), which was most pronounced in patients with autonomic dysfunction compared to patients without (p < 0.05). C6 root diameter showed a significant correlation to the amount of cerebrospinal fluid (CSF)-protein (Pearson correlation, p < 0.05). US shows nerve enlargement in several peripheral nerves including vagal nerve and C6 root in acute phase of GBS and could be an additional diagnostic tool for example, in GBS of atypical onset and autonomic dysfunction.

Ultrasound in the diagnosis of peripheral neuropathy: structure meets function in the neuromuscular clinic

Peripheral nerve ultrasound (US) has emerged as a promising technique for the diagnosis of peripheral nerve disorders. While most experience with US has been reported in the context of nerve entrapment syndromes, the role of US in the diagnosis of peripheral neuropathy (PN) has recently been explored. Distinctive US findings have been reported in patients with hereditary, immune-mediated, infectious and axonal PN; US may add complementary information to neurophysiological studies in the diagnostic work-up of PN. This review describes the characteristic US findings in PN reported to date and a classification of abnormal nerve US patterns in PN is proposed. Closer scrutiny of nerve abnormalities beyond assessment of nerve calibre may allow for more accurate diagnostic classification of PN, as well as contribute to the understanding of the intersection of structure and function in PN.

Ultrasonographic identification of nerve pathology in neuralgic amyotrophy: Enlargement, constriction, fascicular entwinement, and torsion

INTRODUCTION

The aim of this study was to characterize the ultrasonographic findings on nerves in neuralgic amyotrophy.

METHODS

Fourteen patients with neuralgic amyotrophy were examined using high-resolution ultrasound.

RESULTS

Four types of abnormalities were found: (1) focal or diffuse nerve/fascicle enlargement (57%); (2) incomplete nerve constriction (36%); (3) complete nerve constriction with torsion (50%; hourglass-like appearance); and (4) fascicular entwinement (28%). Torsions were confirmed intraoperatively and were seen on the radial nerve in 85% of patients. A significant correlation was found between no spontaneous recovery of nerve function and constriction/torsion/fascicular entwinement (P = 0.007).

CONCLUSION

Ultrasonographic nerve pathology in neuralgic amyotrophy varies in order of severity from nerve enlargement to constriction to nerve torsion, with treatment ranging from conservative to surgical. We postulate that the constriction caused by inflammation is the precursor of torsion and that development of nerve torsion is facilitated by the rotational movements of limbs.

Precise correlation between structural and electrophysiological disturbances in MADSAM neuropathy

Multifocal acquired demyelinating sensory and motor neuropathy is characterised by multifocal clinical deficits. Imaging studies have identified multifocal enlargements of nerve trunks, but a precise correlation between structural abnormalities and electrophysiological dysfunction has not been elucidated. Two patients diagnosed with multifocal acquired demyelinating sensory and motor neuropathy were evaluated with nerve conduction studies, including short segment nerve conduction studies to precisely localise motor conduction block, and ultrasound studies of corresponding nerve trunks. Motor conduction block was identified in each patient (upper limb nerves in two patients), superimposed on additional demyelinating neurophysiological features. Upper limb ultrasound studies demonstrated focal nerve enlargement that precisely correlated with neurophysiological conduction block. The results of this study suggest that factors contributing to focal structural abnormalities in multifocal acquired demyelinating sensory and motor neuropathy are also those that produce conduction block.

Ultrasound and electrophysiologic findings in patients with Guillain-Barré syndrome at disease onset and over a period of six months

OBJECTIVE

To investigate cross-sectional areas (CSAs) of several peripheral nerves including the vagus nerve and the diameter of spinal nerves as measured by nerve ultrasound (NUS) and nerve conduction studies (NCS) in Guillain-Barré syndrome (GBS) patients over at least six months compared to healthy controls.

METHODS

NUS and/or NCS of several nerves, the vagus nerve, and the 5th/6th cervical spinal nerves were performed in patients with GBS at days 2-3 after symptom onset, at days 10-14 after immunoglobulin therapy and after six months compared to healthy controls.

RESULTS

27 GBS-patients and 31 controls were included. Using NUS significant enlargement was found in all measured nerves (P<0.001), except the sural nerve (P=0.086) compared to the controls at onset. The vagus (median 3.0 mm(2) vs. 2.0 mm(2), P<0.0001) and the cervical spinal nerves were significantly enlarged (median 3.5/4.0 mm vs. 2.6/3.2 mm, p<0.0001), the vagus most obviously in patients with autonomic dysregulation (AD, 4.0 mm(2)). Six months later, NCS showed persisting pathology in CMAP-amplitudes with amelioration of F-wave pathology. NUS showed restitution in the spinal nerves (median 2.6/3.2 mm) and the vagus (median 2.0 mm(2)) in all patients excluding the vagus in those with persistent AD (median 4.0 mm(2)). The peripheral nerves did not change significantly (P>0.05).

CONCLUSION

Ultrasonographic detection of cervical spinal nerve enlargement supports the diagnosis of GBS in the early phase. Its regression may be a good parameter for the clinical restitution over time. Vagus enlargement may be a risk marker for development of AD.

SIGNIFICANCE

Ultrasound is a reliable diagnostic follow-up tool in early GBS.

Multifocal motor neuropathy: correlation of nerve ultrasound, electrophysiological, and clinical findings

We present nerve ultrasound findings in multifocal motor neuropathy (MMN) and examine their correlation with electrophysiology and functional disability. Eighty healthy controls and 12 MMN patients underwent clinical, sonographic, and electrophysiological evaluation a mean of 3.5 years (standard deviation [SD] ± 2.1) after disease onset. Nerve ultrasound revealed significantly higher cross-sectional area (CSA) values of the median (forearm, p < 0.001), ulnar (p < 0.001), and tibial nerve (ankle, p < 0.001) when compared with controls. Electroneurography documented signs of significantly lower values of the motor conduction velocity and compound muscle action potentials (cMAPs) in the upper arm nerves (median, ulnar, radial, p < 0.001). A significant correlation between sonographic and electrophysiological findings in the MMN group was found only between cMAP and CSA of the median nerve at the upper arm (r = 0.851, p < 0.001). Neither nerve sonography nor electrophysiology correlated with functional disability. MMN seems to show inhomogeneous CSA enlargement in various peripheral nerves, with weak correlation to electrophysiological findings. Neither nerve sonography nor electrophysiology correlated with functional disability. Multicentre, prospective studies are required to prove the applicability and diagnostic values of these findings.

Nerve Ultrasound in Peripheral Neuropathies: A Review

Peripheral neuropathies are one of the most common reasons for seeking neurological care in everyday practice. Electrophysiological studies remain fundamental for the diagnosis and etiological classification of peripheral nerve impairment. The recent technological development though of high resolution ultrasound has allowed the clinician to obtain detailed structural images of peripheral nerves. Nerve ultrasound mainly focuses on the evaluation of the cross sectional area, cross sectional area variability along the anatomical course, echogenity, vascularity and mobility of the peripheral nerves. An increase of the cross sectional area, hypervascularity, disturbed fascicular echostructure and reduced nerve mobility are some of the most common findings of entrapments neuropathies, such as the carpal or cubital tunnel syndrome. Both the cross-sectional area increase and the hypervascularity detected with the Doppler technique seem to correlate significantly with the clinical and electrophysiological severity of the later mononeuropathies. Significantly greater cross sectional area values of the clinically affected cervical nerve root are often detected in cases of cervical radiculopathy. In such cases, the ultrasound findings seem also to correlate significantly with disease duration. On the other hand, multifocal cross sectional area enlargement of cervical roots and/or peripheral nerves is often documented in cases of immune-mediated neuropathies. None of the later pathological ultrasound findings seem to correlate significantly with the electrophysiological parameters or the functional disability. The aim of this review is to provide a timely update on the role of neuromuscular ultrasound in the diagnostic of the most common entrapment and immune-mediated peripheral neuropathies in clinical practice.

Neuroimaging in diagnosis of atypical polyradiculoneuropathies: report of three cases and review of the literature

Neuroimaging is increasingly used in the study of peripheral nerve diseases, and sometimes may have a pivotal role in the diagnostic process. We report on three patients with atypical chronic inflammatory polyradiculoneuropathy (CIDP) in whom magnetic resonance imaging (MRI) and nerve Ultrasound (US) were crucial for a correct diagnostic work-out. A literature review on MRI and US in acquired demyelinating polyneuropathies is also provided. Awareness of the imaging features of CIDP will assist in confirmation of the diagnosis, institution of the appropriate therapy, and prevention of inadequate or delayed treatment in atypical CIDP.

Nerve ultrasound depicts peripheral nerve enlargement in patients with genetically distinct Charcot-Marie-Tooth disease

OBJECTIVE

To elucidate the ultrasound (US) features of peripheral nerves including nerve roots in patients with different types of Charcot-Marie-Tooth disease (CMT), and the association between US findings, clinical features and parameters of nerve conduction studies (NCS) in CMT1A.

METHODS

US of median, sural and great auricular nerves and the C6 nerve root was performed in patients with CMT1A (n=20), MPZ-associated CMT (n=3), NEFL-associated CMT (n=4), EGR2-associated CMT (n=1), ARHGEF10-associated CMT (n=1) and in controls (n=30). In patients with CMT1A, we analysed the correlations between US findings and the following parameters: age, CMT Neuropathy Score (CMTNS) and NCS indices of the median nerve.

RESULTS

Cross-sectional areas (CSAs) of all the nerves were significantly increased in patients with CMT1A compared with that in controls. In MPZ-associated CMT, increased CSAs were found in the median nerve at wrist and in the great auricular nerve, whereas it was not increased in patients with NEFL-associated CMT. In patients with CMT1A, there was a positive correlation between CMTNS and the CSAs in the median nerves or great auricular nerves. In median nerves in patients with CMT1A, we found a negative correlation between the nerve conduction velocity and the CSA.

CONCLUSIONS

Nerve US may aid in differentiating among the subtypes of CMT in combination with NCS. In CMT1A, the median nerve CSA correlates with the disease severity and peripheral nerve function.

Peripheral nerves and plexus: imaging by MR-neurography and high-resolution ultrasound

PURPOSE OF REVIEW

The purpose of this study is to review advances in magnetic resonance (MR)-neurography and nerve-ultrasound for the precise visualization and localization of nerve lesions not only in nerve trauma or mass lesions, but also in entrapment-related and spontaneously occurring intrinsic neuropathies. These advances may improve the understanding and classification of peripheral neuropathies.

RECENT FINDINGS

Diagnostic studies of MR-neurography and high-resolution ultrasound in entrapment-neuropathies consistently report accurate determination and localization of symptomatic nerve entrapment. Additionally, the longitudinal sampling of nerve-T2-signal over larger areas of coverage has become technically feasible. With this approach, more complex patterns of spatial lesion dispersion in nonfocal neuropathies could be observed with reliable lesion image contrast at the level of individual nerve fascicles. Imaging detection of fascicular lesions allows for more accurate localization, because fascicular lesion types represent a specific pitfall for clinical-electrophysiological examinations. Fascicular hypoechogenicity of high-resolution ultrasound is the correlate of nerve-T2-signal lesions, but contrast is inferior and difficult to quantify. Therefore, nerve enlargement remains the main diagnostic criterion in high-resolution ultrasound. Diffusion-tensor-MR-neurography provides quantitative estimates of fiber structure, which were shown to correlate with aging and focal entrapment.

SUMMARY

High-resolution nerve imaging with extended anatomical coverage is feasible and improves the topographic description of spatial lesion dispersion which is particularly relevant for the discrimination between focal and nonfocal neuropathies.

Nerve ultrasound for differentiation between amyotrophic lateral sclerosis and multifocal motor neuropathy

Ultrasound is useful for non-invasive visualization of focal nerve pathologies probably resulting from demyelination, remyelination, edema or inflammation. In patients with progressive muscle weakness, differentiation between multifocal motor neuropathy (MMN) and amyotrophic lateral sclerosis (ALS) is essential regarding therapy and prognosis. Therefore, the objective of this study was to investigate whether nerve ultrasound can differentiate between ALS and MMN. Systematic ultrasound measurements of peripheral nerves and the 6th cervical nerve root (C6) were performed in 17 patients with ALS, in 8 patients with MMN and in 28 healthy controls. Nerve conduction studies of corresponding nerves were undertaken in MMN and ALS patients. Electromyography was performed in ALS patients according to revised El-Escorial criteria. ANOVA and unpaired t test with Bonferroni correction revealed significant differences in cross-sectional areas (CSA) of different nerves and C6 diameter between the groups. Nerve enlargement was found significantly more frequently in MMN than in other groups (p < 0.001). Receiver operating characteristics analysis revealed detection of enlarged nerves/roots in at least four measurement points to serve as a good marker to differentiate MMN from ALS with a sensitivity of 87.5% and a specificity of 94.1%. Ultrasonic focal nerve enlargement in MMN was often not colocalized with areas of conduction blocks found in nerve conduction studies. Systematic ultrasound measurements in different nerves and nerve roots are valuable for detecting focal nerve enlargement in MMN, generally not found in ALS and thus could serve as a diagnostic marker to differentiate between both entities in addition to electrodiagnostic studies.

Ultrasound differentiation of axonal and demyelinating neuropathies

INTRODUCTION

Ultrasound can be used to visualize peripheral nerve abnormality. Our objective in this study was to prove whether nerve ultrasound can differentiate between axonal and demyelinating polyneuropathies (PNPs).

METHODS

Systematic ultrasound measurements of peripheral nerves were performed in 53 patients (25 with demyelinating, 20 with axonal, 8 with mixed neuropathy) and 8 healthy controls. Nerve conduction studies of corresponding nerves were undertaken.

RESULTS

Analysis of variance revealed significant differences between the groups with regard to motor conduction velocity, compound muscle action potential amplitude, and cross-sectional area (CSA) of different nerves at different locations. Receiver operating characteristic curve analysis revealed CSA measurements to be well suited for detection of demyelinating neuropathies, and boundary values of peripheral nerve CSA could be defined.

CONCLUSIONS

Systematic ultrasound CSA measurement in different nerves helped detect demyelination, which is an additional cue in the etiological diagnosis of PNP, along with nerve conduction studies and nerve biopsy.