Sonographic detection of diffuse peripheral nerve hypertrophy in chronic inflammatory demyelinating polyradiculoneuropathy

Nerve ultrasound for the diagnosis and follow-up of peripheral neuropathies

PURPOSE OF REVIEW

The purpose if this review is to provide an overview of the available data on the use of nerve ultrasound for the diagnosis and follow-up of peripheral neuropathies.

RECENT FINDINGS

During the last decade, nerve ultrasound has been established as a complementary tool for the evaluation of morphological changes mostly for immune-mediated polyneuropathies. Through the development of ultrasound protocols for evaluation of disease-specific sites, nerve ultrasound has proven to be a practical, widely available, reproducible diagnostic tool with no relevant contraindications.

SUMMARY

Cross-sectional area, echogenicity, morphology of the individual nerve fascicles, thickness of the epineurium, vascularization and mobility of the nerve are the main parameters evaluated with nerve ultrasound in polyneuropathies. Patients with typical chronic inflammatory demyelinating polyneuropathy show multifocal nerve enlargements easily visible on the upper extremities and the brachial plexus, whereas its variants show focal nerve enlargements. On the other hand, axonal neuropathies including diabetic neuropathy present with isolated nerve enlargement mostly in compression sites.

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.

Nerve ultrasound and magnetic resonance imaging in the diagnosis of neuropathy

PURPOSE OF REVIEW

This review summarizes the most relevant developments in the fields of nerve ultrasound and MRI in the diagnosis of treatable inflammatory neuropathies over the last 18 months.

RECENT FINDINGS

MRI and nerve ultrasound can accurately identify potentially treatable neuropathies and thereby help to improve diagnosis. Advanced MRI techniques also show potential to dissect pathophysiology. The apparent mismatch between nerve function and morphology is not surprising and reflects different dimensions of the disease process in neuropathies.

SUMMARY

MRI and nerve ultrasound have become useful tools in the diagnosis of inflammatory neuropathies. VIDEO ABSTRACT.

A comparative study of brachial plexus sonography and magnetic resonance imaging in chronic inflammatory demyelinating neuropathy and multifocal motor neuropathy

BACKGROUND AND PURPOSE

To compare the performance of neuroimaging techniques, i.e. high-resolution ultrasound (HRUS) and magnetic resonance imaging (MRI), when applied to the brachial plexus, as part of the diagnostic work-up of chronic inflammatory demyelinating neuropathy (CIDP) and multifocal motor neuropathy (MMN).

METHODS

Fifty-one incident, treatment-naive patients with CIDP (n = 23) or MMN (n = 28) underwent imaging of the brachial plexus using (i) a standardized MRI protocol to assess enlargement or T2 hyperintensity and (ii) bilateral HRUS to determine the extent of nerve (root) enlargement.

RESULTS

We found enlargement of the brachial plexus in 19/51 (37%) and T2 hyperintensity in 29/51 (57%) patients with MRI and enlargement in 37/51 (73%) patients with HRUS. Abnormal results were only found in 6/51 (12%) patients with MRI and 12/51 (24%) patients with HRUS. A combination of the two imaging techniques identified 42/51 (83%) patients. We found no association between age, disease duration or Medical Research Council sum-score and sonographic nerve size, MRI enlargement or presence of T2 hyperintensity.

CONCLUSIONS

Brachial plexus sonography could complement MRI in the diagnostic work-up of patients with suspected CIDP and MMN. Our results indicate that combined imaging studies may add value to the current diagnostic consensus criteria for chronic inflammatory neuropathies.

Sonographic features of peripheral nerves at multiple sites in patients with diabetic polyneuropathy

OBJECTIVE

Diabetic polyneuropathy (DPN) is one of the major complications of diabetes mellitus. Ultrasound has been frequently used for evaluation of peripheral nerves. However, there are few studies that have evaluated multiple peripheral nerves in DPN. In this study, ultrasonographic features of multiple peripheral nerves in upper and lower extremities of DPN patients were investigated and compared with those of healthy controls.

METHODS

This study was a case-control study that enrolled 20 patients with confirmed diagnosis of DPN and 20 healthy controls. The ultrasonography was performed on the sural, tibial, fibular, sciatic, median, ulnar, radial, and musculocutaneous nerves. Nerve cross-sectional area (CSA) was measured at multiple points for each peripheral nerve. The CSAs were compared between DPN and control groups, and analyzed in relation to the clinical characteristics and electrophysiologic findings.

RESULTS

The CSAs were significantly larger in the DPN group for sural nerve, fibular nerve at the fibular head level, median nerve at the carpal tunnel and mid-humerus level, ulnar nerve at the cubital tunnel outlet and mid-humerus level, and radial nerve at the spiral groove. The CSAs of sural nerve, tibial nerve and median nerve were significantly correlated with electrophysiologic findings. The sural nerve CSA revealed significant correlation with HbA1c.

CONCLUSIONS

These results suggest that the ultrasonography can provide useful information in diagnosis and evaluation of DPN.

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.

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.

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.

Ultrasonographic findings in hereditary neuropathy with liability to pressure palsies

OBJECTIVES

The aims of this study were to evaluate the sonographic findings of patients with hereditary neuropathy with liability to pressure palsies (HNPP) and to examine the correlation between sonographic and electrophysiological findings.

METHODS

Nine patients whose electrophysiological findings indicated HNPP and whose diagnosis was confirmed by genetic analysis were enrolled in the study. The median, ulnar, peroneal, and tibial nerves were evaluated by ultrasonography.

RESULTS

We ultrasonographically evaluated 18 median, ulnar, peroneal, and tibial nerves. Nerve enlargement was identified in the median, ulnar, and peroneal nerves at the typical sites of compression. None of the patients had nerve enlargement at a site of noncompression. None of the tibial nerves had increased cross-sectional area (CSA) values. There were no significant differences in median, ulnar, and peroneal nerve distal motor latencies (DMLs) between the patients with an increased CSA and those with a normal CSA. In most cases, there was no correlation between electrophysiological abnormalities and clinical or sonographic findings.

DISCUSSION

Although multiple nerve enlargements at typical entrapment sites on sonographic evaluation can suggest HNPP, ultrasonography cannot be used as a diagnostic tool for HNPP. Ultrasonography may contribute to the differential diagnosis of HNPP and other demyelinating polyneuropathies or compression neuropathies; however, further studies are required.

Ultrasound evaluation in transthyretin-related amyloid neuropathy

INTRODUCTION

Familial amyloid polyneuropathy is a rare condition caused by mutations of the transthyretin gene (TTR). We assessed the pattern of nerve ultrasound (US) abnormalities in patients with TTR-related neuropathy.

METHODS

Seven patients with TTR-related neuropathy (TTR-N) and 5 asymptomatic TTR-mutation carriers (TTR-C) underwent neurological examination, nerve conduction studies, and US evaluation.

RESULTS

Multifocal US abnormalities were identified in 6 of 7 TTR-N patients. A single patient with only a mild sensory polyneuropathy had normal nerves on US evaluation. In the TTR-C, we only detected an enlarged ulnar nerve at the elbow. Interestingly, disease severity correlated with number of nerves affected on US evaluation.

CONCLUSIONS

No specific pattern of US abnormalities was identified in this cohort. However, in TTR-related amyloid neuropathy, US may be a helpful tool in monitoring disease progression, and/or clinical response to pharmacological treatment.

Different patterns of nerve enlargement in polyneuropathy subtypes as detected by ultrasonography

The purpose of our study was to examine how the pathologic type of polyneuropathy affects nerve size as assessed by high-resolution ultrasonography with a 15 MHz transducer. Cross-sectional area (CSA) of the C5-C7 nerve roots and several upper and lower limb nerves at multiple sites was measured in 38 patients with acquired diffuse sensorimotor demyelinating or axonal polyneuropathy and in 34 healthy control subjects. Significant differences were found among the groups for all nerve and root segments: Both types of polyneuropathy are characterized by nerve enlargement in comparison to controls, but in different patterns. In demyelinating polyneuropathies, an additional degree of nerve thickening appears in proximal upper limb nerves and cervical nerve roots compared with axonal polyneuropathies. With respect to the other nerves, a similar degree of nerve enlargement was observed in both patient groups. These results highlight that ultrasonography may be a complementary tool in differentiating polyneuropathies.

Correlation of nerve ultrasound, electrophysiological and clinical findings in chronic inflammatory demyelinating polyneuropathy

BACKGROUND AND PURPOSE

We present the nerve ultrasound findings in chronic inflammatory demyelinating polyneuropathy (CIDP) and examine their correlation with electrophysiology and functional disability.

METHODS

A total of 75 healthy controls and 48 CIDP patients underwent clinical, sonographic and electrophysiological evaluation a mean of 3.9 years(SD+/-2.7) after disease onset.

RESULTS

Nerve ultrasound revealed statistically significant higher cross-sectional area (CSA) values of the median (P<.0001), ulnar (P<.0001), radial (P<.0001), tibial (P<.0001), fibular nerve(P<.0001) in most of the anatomic sites and brachial plexus (supraclavicular, P<.0001;interscalene space, P = .0118),when compared to controls. The electroneurography documented signs of permanent axonal loss in the majority of peripheral nerves. A correlation between sonographic and electrophysiological findings was found only between the motor conduction velocity and CSA of the tibial nerve at the ankle (r = -.451, P = .007). Neither nerve sonography nor electrophysiology correlated with functional disability. The CSA of the median nerve in carpal tunnel and the ulnar nerve in Guyon's canal correlated with disease duration (P = .036, P = .027 respectively).

DISCUSSION

CIDP seems to show inhomogenous CSA enlargement in brachial plexus and peripheral nerves, with weak correlation to electrophysiological findings. Neither nerve sonography nor electrophysiology correlated with functional disability in CIDP patients. Multicenter, prospective studies are required to proof the applicability and diagnostic values of these findings.

Pattern analysis of nerve enlargement using ultrasonography in chronic inflammatory demyelinating polyneuropathy

OBJECTIVE

Focal nerve enlargement is a characteristic finding in chronic inflammatory demyelinating polyneuropathy (CIDP). We performed this study to assess the distribution of nerve enlargement through ultrasonographic examination of peripheral nerves and to correlate the ultrasonographic findings with clinical features.

METHODS

To compare the ultrasonographic features of 10 subjects with CIDP with those of 18 healthy controls, we bilaterally measured the cross-sectional areas (CSA) of the vagus, brachial plexus, musculocutaneous, median, ulnar, radial, sciatic, tibial, common peroneal, and sural nerves. We also analyzed correlations between CSAs and various clinical and electrophysiological features.

RESULTS

Mean CSAs were significantly larger in CIDP patients than controls, especially at proximal and non-entrapment sites. CSAs were significantly correlated with muscle strength at initial presentation, but not at the time of ultrasonography. The CSAs of the median and ulnar nerves at the mid-forearm, tibial nerve at 7 cm proximal to the medial malleolus, and sural nerve correlated with the nerve conduction velocity of the corresponding region.

CONCLUSION

Ultrasonography revealed widely distributed nerve enlargement, especially in proximal regions and non-entrapment sites, in patients with CIDP compared with healthy controls. Nerve enlargement correlated well with the electrophysiologic function of the nerve, but not current clinical status.

SIGNIFICANCE

Pattern analysis of nerve enlargement using ultrasonography is a supportive tool in the diagnosis of CIDP.

Heterogeneity of root and nerve ultrasound pattern in CIDP patients

OBJECTIVE

The few published ultrasound (US) studies on chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) report diffusely increased cross-sectional area (CSA) of nerves. The data are, however, heterogeneous and correlations with clinical history or disease severity are lacking.

METHODS

Thirty-four patients with CIDP underwent US nerve evaluation by two neurologists blinded to clinical data. US nerve pattern for each patient was defined by a third neurologist blinded to clinical data. Three US classes were identified based on CSA and echogenicity: large nerves with hypoechoic nerves/fascicles (class 1); large nerves with heterogeneous hypo- and hyperechoic fascicles (class 2); normal size nerve but abnormal hyperechoic array (class 3).

RESULTS

In all patients, US nerve changes were observed: in most of the cases, enlarged nerves or nerve segments were observed. The three 'classes' of US nerve changes significantly correlated (R: 0.68, p<0.001) with disease duration, but not with age or Inflammatory Neuropathy Cause and Treatment (INCAT) disability score.

CONCLUSIONS

US may be of adjunctive diagnostic value in CIDP assessment. Nerve morphological changes may mirror the underlying pathophysiological mechanisms and seem to correlate with disease duration.

SIGNIFICANCE

These results offer the possibility of exploring the use of US to assess CIDP disease activity and treatment.

Multifocal enlargement and increased vascularization of peripheral nerves detected by sonography in CIDP: a pilot study

OBJECTIVE

Detection of nerve enlargement in polyneuropathies by sonography is a new research area. No systematic investigation has been done yet in chronic inflammatory demyelinating polyneuropathy (CIDP). Therefore we investigated this in CIDP.

METHODS

Eleven patients with CIDP fulfilling the international criteria on CIDP underwent ultrasonographic examination of the median, ulnar, fibular and posterior tibial nerves and sometimes the brachial plexus bilaterally, using a standardized protocol. We assessed presence of nerve thickening and increased nerve vascularization.

RESULTS

In 7 of the 11 patients multiple nerve enlargements were detected: ulnar nerve 7, fibular nerve 5, posterior tibial nerve 4 and median nerve in 4 patients. The number of enlarged nerves was related with the MRC sum-score (p=0.03) and the total protein in the cerebrospinal fluid (CSF) at diagnosis (p=0.02). Increased vascularization was seen in 6 of the 11 patients: 4 in one nerve and in 2 in multiple nerves. The number of nerves with increased vascularization was associated with the number of enlarged nerves (p=0.01) and total protein in the CSF (p=0.006).

CONCLUSION

Multiple nerve enlargements occur in CIDP showing a relation with a lower MRC sum-score, increased nerve vascularization and a higher total protein of the CSF.

SIGNIFICANCE

Our findings of nerve enlargement and increased nerve vascularization may be tools to monitor disease activity in CIDP, but further studies are needed.

Nerve ultrasound follow-up in a child with Guillain-Barré syndrome

INTRODUCTION

Nerve ultrasound has been used increasingly in neurophysiology laboratories, but data on Guillain-Barré syndrome (GBS) are still limited, and no follow-up studies are available.

CASE REPORT

An 8-year-old boy was admitted with severe demyelinating GBS. Serial neurophysiological evaluations were performed initially and in follow-up. Ultrasound studies showed diffuse and heterogeneous nerve swelling and focal enlargement of single fascicles inside the nerve. Together with clinical and electrophysiological improvement, progressive normalization of ultrasound changes was seen.

CONCLUSIONS

Ultrasound demonstrated structural nerve abnormalities in GBS. These changes normalized as the patient improved clinically and electrophysiologically. Further studies are needed to elucidate the diagnostic and prognostic value of ultrasound in GBS.

Ultrasonography in the diagnosis of peripheral nerve disease

INTRODUCTION

High-resolution ultrasound (US) of the peripheral nerves is now a standard means of assessing neuromuscular disorders in many centers. Currently used in conjunction with electrodiagnostic (EDX) studies, nerve US is especially effective in the diagnosis of entrapment neuropathies.

AREAS COVERED

This article reviews the basic physics of peripheral nerve US, guidelines for its current use and future directions. Advantages of using nerve US alongside EDX studies are outlined along with current limitations of testing. The role of US in the diagnosis of entrapment neuropathy is emphasized, particularly in carpal tunnel syndrome (CTS). US assisted diagnosis of peripheral nerve tumors, hereditary neuropathy and dysimmune neuropathy and traumatic injuries is also described.

EXPERT OPINION

US is a powerful tool in the assessment of peripheral nerve disease. Nerve US is an evolving, young discipline. There is still much to learn, but current evidence supports US imaging of all patients presenting for evaluation of possible mononeuropathy. With improvements in resolution, the introduction of US contrast agents and objective measures of nerve echogenicity, there is promise for further expanding its role in the diagnosis of all peripheral neuropathies.

Ultrasound evaluation of peripheral neuropathy in POEMS syndrome

INTRODUCTION

Polyneuropathy, organomegaly, endocrinopathy, M protein, skin changes (POEMS) syndrome is a rare multisystem disorder associated with plasma cell dyscrasia whose main neurological feature is a demyelinating polyneuropathy. The aim of our study was to assess the pattern of ultrasound (US) nerve abnormalities in POEMS syndrome patients.

METHODS

Eight POEMS syndrome patients underwent neurological examination and US evaluation of the median, ulnar, fibular, tibial, and sural nerves. Nerve cross-sectional area and echogenicity abnormalities were analyzed.

RESULTS

US abnormalities were mostly localized at entrapment sites. Enlargements outside the entrapment sites were uncommon. No correlation was found between muscle weakness and focal US findings.

CONCLUSIONS

No specific pattern of US abnormalities was identified in this cohort of patients with POEMS syndrome. The lack of correlation between US and clinical findings may be secondary to the chronic nerve damage that is common in POEMS syndrome, where the diagnosis is often delayed.

Sonographic evaluation of peripheral nerve injuries following the Wenchuan earthquake

PURPOSE

To analyze retrospectively the sonographic characteristics of the peripheral nerve injuries (PNIs) resulted from Wunchuan earthquake.

METHODS

The sonographic images of 38 patients with surgically proved PNIs were reviewed and compared with the surgical findings.

RESULTS

A total of 78 nerves in 38 patients were found injured in surgery, which included 16 median nerves in the forearm (20.5%), 6 ulnar nerves in the forearm or arm (7.7%), 8 radial nerves in upper limb (10.0%), 8 sciatic nerves (10.3%) in gluteal region, 17 tibial nerves in the leg (21.8%), and 23 peroneal nerves (29.5%). The most common injured nerve in the lower extremity was the peroneal nerve (29.5%) and in upper extremity was the median nerve (20.5%). Sonography correctly diagnosed 72 earthquake-related nerve injuries (92.3%), which included 5 complete disruption (6.4%), 4 partial disruption (5.1%), 63 nerve entrapment (88.5%, included 1 entrapment by bone calus, 38 entrapments by the scar tissue, 13 entrapments by the thickened muscle or tendinous arch, and 11 entrapment in the narrowed osteofibrous tunnels).

CONCLUSIONS

Nerve entrapment injury was the common sonographic finding in earthquake-related PNI.

Sonographic findings in a case of polyneuropathy associated with POEMS syndrome

Polyneuropathy, organomegaly, endocrinopathy, M protein and skin changes (POEMS) syndrome is a rare multi-system disease. We describe the ultrasonography (US) and color Doppler ultrasonography (CDUS) findings of peripheral neuropathy in a patient with POEMS syndrome. In US examination, peripheral nerves were found to be diffusely thickned in both upper limbs. CDUS imaging showed arterial blood flow with low systolic peaks on the nerves.

Chronic inflammatory demyelinating polyneuropathy: diagnosis and management

Over the course of 8 weeks, a 50-year-old man developed progressive bilateral leg and arm weakness, with numbness and tingling of the feet and hands. His symptoms persisted for 6 months, with impaired manual dexterity, arm weakness when brushing his teeth, tripping when walking, inability to climb stairs and gait imbalance. On examination, there is mild proximal and distal weakness of the upper and lower extremity muscles, length-dependent sensory loss of vibratory perception and joint position sense, areflexia, positive Romberg test and steppage gait with bilateral foot drop. Motor nerve conduction studies of the arms and legs show partial conduction blocks in several nerves with nonuniform slowing, and sensory responses are absent in the hands, however, normal sural responses are noted. Lumbar puncture reveals acellular cerebrospinal fluid with elevated protein. After 2 months following treatment, his strength and gait improved significantly, and his sensory symptoms resolved.

Peripheral nerve size in normals and patients with polyneuropathy: an ultrasound study

Ultrasound has been used for visualizing peripheral nerve pathology. Our goal was to use ultrasound to quantitate the sizes of upper extremity nerves along their length in control subjects and patients with neuropathy. We measured median and ulnar nerve cross-sectional areas (NCSA) in the arms of 190 subjects, including 100 with neuropathies and 90 controls. We found that NCSAs in healthy child and adult controls were greater with increasing height, at proximal sites, and at sites of entrapment. Nerves were enlarged in all Charcot-Marie-Tooth 1A (CMT-1A) (11 of 11; 100%), most chronic inflammatory demyelinating polyneuropathy (CIDP) (31 of 36; 86%), half of Guillain-Barré syndrome (GBS) (8 of 17; 47%), but few axonal neuropathy (7 of 36, 19%) subjects. In GBS, nerve enlargement occurred early and with minimal electrodiagnostic abnormalities in some patients. We conclude that NCSA measured by ultrasound is a quantifiable marker of nerve features that should be corrected for patient characteristics and nerve site. NCSA is generally larger in demyelinating than it is in axonal polyneuropathies.

Diagnostic nerve ultrasound in Charcot-Marie-Tooth disease type 1B

Ultrasound is emerging as a useful tool for evaluation of neuromuscular conditions, because it can provide high-resolution anatomic information to complement electrodiagnostic data. There have been few studies in which ultrasound was used to assess the peripheral nerves of individuals with Charcot-Marie-Tooth (CMT) disease and none involving CMT type 1B. In this study we compared nerve cross-sectional area in individuals from a single large family with CMT 1B with normal, healthy controls. We also assessed for cranial nerve enlargement in those with CMT 1B with cranial neuropathies compared to those with CMT 1B without cranial neuropathies. Individuals with CMT 1B have significantly larger median and vagus nerves than healthy controls, but no difference was seen in cranial nerve size between those with versus those without cranial neuropathies. This is the first study to characterize the ultrasonographic findings in the peripheral nerves of individuals with CMT 1B.

Neuromuscular ultrasound

High-resolution ultrasound now is capable of imaging muscle and nerve in fine detail. It is sensitive in detecting chronic myopathies and neurogenic atrophy and may be able to detect subtle changes associated with acute denervation. It is particularly well suited to the study of fasciculations and kinesiology. Recent studies show that ultrasound also is capable of imaging most peripheral nerves,including small branches, and of sensitively measuring the swelling that follows chronic compression. This noninvasive technology holds considerable promise for providing anatomic information to complement other tests of nerve and muscle function.

Detection of cervical nerve root hypertrophy by ultrasonography in chronic inflammatory demyelinating polyradiculoneuropathy

Several studies have demonstrated abnormal MRI findings in chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), especially hypertrophy and abnormal enhancement of spinal nerve roots, but there have been few reports on ultrasonographic findings of spinal nerve roots in CIDP. To determine whether ultrasonography (US) enables detection of hypertrophy of the cervical nerve roots, how frequently hypertrophy occurs in CIDP, and whether US findings correlate with any clinical and laboratory features, US of cervical nerve roots was performed using a 7.5-MHz linear-array transducer in 13 CIDP patients and 35 control subjects. A coronal oblique plane with a transducer placed on the lateral side of the neck was used to visualize the cervical nerve roots just after their point of exit from the cervical foramina, and their diameters were measured. US demonstrated hypertrophy of the cervical nerve roots in 9 (69%) of the 13 CIDP patients as compared with findings in control subjects. The degree of hypertrophy was significantly associated with the level of CSF protein (chi2=5.8, p<0.05, logistic simple regression analysis) but not with other clinical features. US is considered to be a useful method for evaluating cervical nerve root hypertrophy, which is frequently seen in patients with CIDP, particularly in patients with elevated level of CSF protein.

Ultrasound of nerve and muscle

Over the last two decades, ultrasound has developed into a useful technology for the evaluation of diseases of nerve and muscle. Since it is currently not used at by the majority of clinicians involved in diagnosis or care of patients with neuromuscular disorders, this review briefly describes the technical aspects of ultrasound and its physical principles. It relates normal muscle anatomy and movement to ultrasound images in the axial and sagittal planes and follows with a discussion of ultrasound findings in chronic muscle disease. These include evident atrophy and the loss of the hypoechoic architecture of normal muscle tissue. It highlights evolving uses of the technique to measure other pathologic changes in disease including altered muscle dynamics. With high-resolution instruments nerve imaging has now become standard, and the relationships of median nerve anatomy and observations of static and dynamic images from ultrasound are reviewed. Changes seen in carpal tunnel syndrome include significant increases in the cross-sectional area of the nerve just proximal to the site of compression, loss of hyperechoic intensities within nerve, and reduced mobility. Preliminary use of the technique for the study of other nerves is reviewed as well. Ultrasound is an ideal tool for the clinical and research investigation of normal and diseased nerve and muscle complementary to existing diagnostic techniques. As the technology continues to evolve, it will likely assume a more significant role in these areas as those most able to exploit its potential, clinical neurophysiologists and neuromuscular clinicians, incorporate its use at the bedside.

The ultrasonographic appearance of the femoral nerve and cases of iatrogenic impairment

OBJECTIVE

To assess the feasibility of ultrasonography of femoral nerves in a cadaveric specimen, healthy volunteers, and patients.

METHODS

In 1 unembalmed cadaveric specimen (female, 90 years) and 20 healthy volunteers (9 male and 11 female, 18-50 years; n = 40 scans), the topographic features, cross-sectional shapes (oval or triangular), and cross-sectional areas of the femoral nerves were evaluated by ultrasonography (5- to 12-MHz broadband linear array). In a subsequent study, 7 consecutive patients with postoperative findings assigned to the femoral nerve were evaluated and assessed by a neurologist.

RESULTS

The mean +/- SD anteroposterior and mediolateral diameters of the femoral nerves in the volunteers were 3.1 +/- 0.8 and 9.8 +/- 2.1 mm, respectively, at an average cross-sectional area of 21.7 +/- 5.2 mm2. The cross-sectional shape was oval in 67.5% superior to the inguinal ligament and in 95% inferior to the ligament. The infrainguinal femoral nerve showed variable distances to the femoral artery. In the subsequent patient study, 5 patients had swelling of the femoral nerve in the affected side. In 1 patient, the nerve had a blurred echo structure due to a hematoma. In 1 patient, major damage of the femoral nerve was ruled out clearly.

CONCLUSIONS

Ultrasonography allows the depiction and assessment of the femoral nerve from about 10 cm superior to 5 cm inferior to the inguinal ligament. In this region, ultrasonography is helpful in detection of impairments and, therefore, in decisions about planning and even acceleration of further treatment.

Sonography of peripheral nerves: technique, anatomy, and pathology

Sonography provides a unique method for evaluating peripheral nerves because of its high spatial resolution, its ability to follow structures over long distances in a limb, and its dynamic nature that allows movement of patient and transducer. When combined with the wide availability and relatively low cost, sonography is an excellent modality for peripheral nerve assessment. The authors review the techniques used in assessment of peripheral nerves, the relevant anatomy, and common pathologic processes.

Sonographic detection of diffuse peripheral nerve enlargement in hereditary neuropathy with liability to pressure palsies

Hereditary neuropathy with liability to pressure palsies (HNPP) is a disorder characterized by a tendency to develop focal neuropathies after trivial traumas. On teased nerve fiber studies, sausage-shaped myelin sheath swellings (tomacula) are found. We report the sonographic findings in a patient with genetically proven HNPP. We were able to demonstrate enlargement of several peripheral nerves, even nerves that were clinically unaffected. Enlargement was found not only at typical nerve entrapment sites but also outside these sites. This diffuse nerve enlargement may play an important role in the pathogenesis of entrapment neuropathies in HNPP patients.

Chronic inflammatory demyelinating polyradiculoneuropathy

In chronic inflammatory demyelinating polyradiculopathy differing clinical subtypes are beginning to emerge as has already occurred with the Guillain-Barré syndrome. However, neither pathogenic correlates nor particular therapeutic approaches have yet been defined for these subgroups. The neurophysiological techniques of terminal latency index and of modified F ratio help differentiate chronic inflammatory demyelinating polyradiculopathy from IgM paraproteinaemic neuropathy. Diagnosis may be assisted by magnetic resonance imaging studies in which enlarged nerve roots and plexuses and gadolinium enhancement may be evident. Further insight into pathogenesis has come from studies showing pathogenic antibodies in a small percentage of patients. Immunohistological studies examining the presence of adhesion, co-stimulatory and antigen presenting molecules in nerve biopsies have shown that T cell activation can be initiated and perpetuated within nerve and that Schwann cells possess the necessary markers to function as antigen presenting cells. Recent clinical trials have confirmed the therapeutic short term efficacy of intravenous immunoglobulin and Prednisone.