High-resolution ultrasound of peripheral nerves in systemic sclerosis: a pilot study of computer-aided quantitative assessment of nerve density

The evaluation of tibial nerve using shear-wave elastography and ultrasound in patients with systemic sclerosis: A cross-sectional study

Objectives

The study aimed to evaluate stiffness and the cross-sectional area (CSA) of the tibial nerve (TN) using shear wave elastography (SWE) and ultrasound (US) and investigate the relationship of these with disease activity, quality of life, and severity of neuropathic pain in patients with systemic sclerosis (SSc).

Patients and methods

This cross-sectional study included 28 SSc patients (1 male, 27 females; mean age: 50±11 years; range, 28 to 67 years) and 22 age- and sex-matched healthy controls (4 males, 18 females; mean age: 48±6 years; range, 37 to 66 years) between March and April 2022. US and SWE were performed on the TN, and CSA and nerve stiffness were measured. The TN was examined by a radiologist, 4 cm proximal to the medial malleolus. A few days later, an evaluation was performed in the second session by a second observer to investigate inter-and intraobserver agreement. Interobserver agreement was evaluated using the intraclass correlation coefficient (ICC). The Scleroderma Health Assessment Questionnaire, European League Against Rheumatism European Scleroderma Trial and Research (EUSTAR) group activity index, and Douleur-Neuropathique 4 scores of the patients were evaluated. Correlations between the questionnaires and measurements of nerve stiffness and CSA were assessed.

Results

Patients with SSc had significantly higher stiffness and CSA values of the right TN compared to healthy controls (p<0.001 and p=0.015, respectively). The nerve stiffness values of the right TN were positively correlated with the EUSTAR activity index (p=0.004, r=0.552). The CSA of the left TN was larger in patients with SSc (21.3±4.9 mm2 ) than in controls (12.8±3.4 mm2 ), and the nerve elasticity was positively correlated with the EUSTAR activity index (p=0.001, r=0.618). The interobserver agreement was moderate to good for measuring stiffness and CSA of the TN (ICC were 0.660 and 0.818, respectively). There was a good to excellent intraobserver agreement for measuring stiffness and CSA of TN (ICC were 0.843 and 0.940, respectively).

Conclusion

The increased disease activity in patients with SSc is associated with TN involvement, which can be demonstrated by US and SWE.

Quantitative Ultrasound Techniques Used for Peripheral Nerve Assessment

AIM

This review article describes quantitative ultrasound (QUS) techniques and summarizes their strengths and limitations when applied to peripheral nerves.

METHODS

A systematic review was conducted on publications after 1990 in Google Scholar, Scopus, and PubMed databases. The search terms "peripheral nerve", "quantitative ultrasound", and "elastography ultrasound" were used to identify studies related to this investigation.

RESULTS

Based on this literature review, QUS investigations performed on peripheral nerves can be categorized into three main groups: (1) B-mode echogenicity measurements, which are affected by a variety of post-processing algorithms applied during image formation and in subsequent B-mode images; (2) ultrasound (US) elastography, which examines tissue stiffness or elasticity through modalities such as strain ultrasonography or shear wave elastography (SWE). With strain ultrasonography, induced tissue strain, caused by internal or external compression stimuli that distort the tissue, is measured by tracking detectable speckles in the B-mode images. In SWE, the propagation speed of shear waves, generated by externally applied mechanical vibrations or internal US "push pulse" stimuli, is measured to estimate tissue elasticity; (3) the characterization of raw backscattered ultrasound radiofrequency (RF) signals, which provide fundamental ultrasonic tissue parameters, such as the acoustic attenuation and backscattered coefficients, that reflect tissue composition and microstructural properties.

CONCLUSIONS

QUS techniques allow the objective evaluation of peripheral nerves and reduce operator- or system-associated biases that can influence qualitative B-mode imaging. The application of QUS techniques to peripheral nerves, including their strengths and limitations, were described and discussed in this review to enhance clinical translation.

Considerations for Hand Surgery in Patients With Scleroderma

Systemic sclerosis (scleroderma, SSc) is an autoimmune disease that causes significant dysfunction to multiple organ systems, including the musculoskeletal system. It poses significant challenges to the hand surgeon, including calcinosis, ischemic changes, Raynaud phenomenon, tendinopathies, synovitis, and joint contractures. Patients with SSc also suffer from multiorgan dysfunction, which makes them high-risk surgical patients. The hand surgeon must understand the pathophysiology, treatment strategies, and special operative considerations required in this population to avoid complications and help maintain or improve hand function.

High-resolution ultrasound of peripheral neuropathies in rheumatological patients: An overview of clinical applications and imaging findings

Peripheral neuropathies are surprisingly common and can be associated with a number of conditions, including rheumatological diseases. Whether the co-existence of peripheral neuropathies with rheumatological disorders is coincidental or related to a common pathogenic mechanism, these disabling conditions can affect the outcome of rheumatological patients and should be targeted with specific treatment. The clinical presentation of peripheral neuropathy can be multifaceted and difficult to recognize in polysymptomatic patients. However, physicians adopting state-of-art diagnostic strategies, including nerve imaging, may improve the detection rate and management of neuropathies. In particular, a diagnostic approach relying exclusively on clinical history and nerve conduction studies may not be sufficient to disclose the etiology of the nerve damage and its anatomical location and thus requires integration with morphological studies. High-Resolution Ultrasound (HRUS) is increasingly adopted to support the diagnosis and follow-up of both joint disorders in rheumatology and peripheral neuropathies of different etiologies. In this review, the different types of nerve disorders associated with the most common syndromes of rheumatological interest are discussed, focusing on the distinctive sonographic features.

Clinical Manifestations, Pathogenesis, Diagnosis and Treatment of Peripheral Neuropathies in Connective Tissue Diseases: More Diverse and Frequent in Different Subtypes than Expected

Purpose of review: To discuss and summarize recent findings in peripheral neuropathy (PN) related to connective tissue diseases (CTD) including its prevalence, clinical manifestations, pathogenesis, diagnosis and treatment. Recent findings: Although PN is a common complication in CTD and has been well studied, recent research has shown that PN is more diverse and frequent in different subtypes of CTD than was expected. The incidence of PN in Sjögren’s syndrome and rheumatoid arthritis (RA) varies according to different disease subtypes, and the pathogenesis of neuropathic pain in different subtypes of eosinophilic granulomatosis with polyangiitis (EGPA) may also differ. Neurogenic inflammation, autoantibody-mediated changes, ischemia of the vascular wall and metabolic mechanisms have been shown to contribute to the pathogenesis of PN in CTD. Moreover, allergic inflammation has been recently identified as a possible new mechanism producing peripheral neuropathic pain associated with MPO-ANCA negative EGPA patients. Glucocorticoids are routinely used to relieve pain caused by PN. However, these steroids may cause hyperalgesia, exacerbate neuropathic pain, and activate the early phase of pain induction and produce hyperalgesia. Recently, neuroactive steroids, such as progesterone, tetrahydroprogesterone and testosterone, have been shown to exert protective effects for several PN symptoms, and in particular neuropathic pain. Neuroactive steroids will be an interesting topic for future research into PN in CTD. Summary: It is essential for the diagnosis and treatment of PN in CTD to be updated. Timely diagnosis, appropriate treatments, and multidisciplinary care are essential to minimize morbidity and decrease the risk of permanent neurologic deficits. Further studies are needed to guide diagnosis and treatment.

Epidemiology and treatment of peripheral neuropathy in systemic sclerosis

OBJECTIVE

The epidemiology and treatment of peripheral neuropathy in systemic sclerosis (SSc) is poorly understood. The objectives of this study were to evaluate the incidence, prevalence, risk factors, and treatments of peripheral neuropathy in SSc.

METHODS

A systematic review of Medline, Embase and CINAHL databases for literature reporting peripheral neuropathy in SSc was performed. Studies evaluating incidence, prevalence, risk factors, and treatments were synthesized. Meta-analysis using a random effects model was used to evaluate the prevalence of peripheral neuropathy.

RESULTS

113 studies reported 949 subjects with at least one type of peripheral neuropathy out of 2143 SSc patients studied. The mean age was 48.5 years. The mean time between SSc onset and detection of peripheral neuropathy was 8.85 years. The pooled prevalence of neuropathy was 27.4% (95%CI 22.4% - 32.7%). Risk factors for peripheral neuropathy in SSc included advanced diffuse disease, anticentromere antibodies, calcinosis cutis, ischemia of the vasa nervosum, iron deficiency anemia, metoclopramide, pembrolizumab, silicosis and uremia. There were 73 subjects with successful treatments (n=36 restoring sensation, n=37 restoring motor or sensorimotor function). Treatments included decompression surgery, prednisone, cyclophosphamide, carbamazepine, transcutaneous electrical nerve stimulation, tricyclic antidepressants and IVIG.

CONCLUSION

All-cause peripheral neuropathy is not uncommon in SSc. Compression neuropathies can be treated with decompression surgery. Observational data reporting immunosuppressive and anticonvulsants to treat peripheral neuropathy in SSc is limited and conflicting. This data provides the signal of effect to justify RCT to evaluate the efficacy of these interventions.

The role of ultrasound in systemic sclerosis: On the cutting edge to foster clinical and research advancement

Ultrasound has been widely explored in systemic sclerosis in the clinical and research settings. Ultrasound allows a non-invasive and ionising radiation-free 'window' into this complex disease and is well-suited to repeated examinations. Ultrasound provides novel insights into the pathogenesis and measurement of disease in systemic sclerosis, including early (preclinical) internal organ involvement. The purpose of this review is to describe the role of ultrasound to foster clinical and research advancements in systemic sclerosis relating to (1) musculoskeletal, (2) digital ulcer, (3) lung disease and (4) skin disease. We also highlight unmet needs which much be addressed for ultrasound to assume a central role in systemic sclerosis clinical care and research.

Peripheral nervous system manifestations of rheumatological diseases

Rheumatological diseases result in immune-mediated injury to not only connective tissue, but often components of the peripheral nervous system. These overlap conditions can be broadly categorized as peripheral neuropathies and overlap myositis. The peripheral neuropathies are distinctive as many have unusual presentations such as non-length-dependent, small fiber neuropathies and sensory neuronopathies (both due to dorsal root ganglia dysfunction), multiple mononeuropathies (e.g. vasculitic neuropathies), and even cranial neuropathies. Overlap myositis is increasingly recognized and is often associated with specific autoantibodies. Sarcoidosis also has widespread neurological manifestations and impacts both the peripheral nerves and muscle. Much work is needed to fully characterize the vast presentations of these overlap diseases. Given the rarity of these disorders, they are understudied, resulting in significant knowledge gaps with regards to their underlying pathophysiology and the best treatment approach. A basic knowledge of these disorders is mandatory for both practicing rheumatologists and neurologists as prompt recognition and early initiation of immunotherapy may prevent significant morbidity and permanent disability.

Fascicular Ratio Pilot Study: High-Resolution Neurosonography-A Possible Tool for Quantitative Assessment of Traumatic Peripheral Nerve Lesions Before and After Nerve Surgery

BACKGROUND

Clinical and electrophysiological assessments prevail in evaluation of traumatic nerve lesions and their regeneration following nerve surgery in humans. Recently, high-resolution neurosonography (HRNS) and magnetic resonance neurography have gained significant importance in peripheral nerve imaging. The use of the grey-scale-based "fascicular ratio" (FR) was established using both modalities allowing for quantitative assessment.

OBJECTIVE

To find out whether FR using HRNS can assess nerve trauma and structural reorganization in correlation to postoperative clinical development.

METHODS

Retrospectively, 16 patients with operated traumatic peripheral nerve lesions were included. The control group consisted of 6 healthy volunteers. All imaging was performed with a 15 to 6 MHz ultrasound probe (SonoSite X-Porte; Fujifilm, Tokyo, Japan). FR was calculated using Fiji () on 8-bit-images ("MaxEntropy" using "Auto-Threshold" plug-in).

RESULTS

Thirteen of 16 patients required autologous nerve grafting and 3 of 16 extra-intraneural neurolysis. There was no statistical difference between the FR of nonaffected patients' nerve portion with 43.48% and controls with FR 48.12%. The neuromatous nerve portion in grafted patients differed significantly with 85.05%. Postoperatively, FR values returned to normal with a mean of 39.33%. In the neurolyzed patients, FR in the affected portion was 78.54%. After neurolysis, FR returned to healthy values (50.79%). Ten of 16 patients showed clinical reinnervation.

CONCLUSION

To our best knowledge, this is the first description of FR using HRNS for quantitative assessment of nerve damage and postoperative structural reorganization. Our results show a significant difference in healthy vs lesioned nerves and a change in recovering nerve portions towards a more "physiological" ratio. Further evaluation in larger patient groups is required.

Ultrasound elastography in the evaluation of peripheral neuropathies: a systematic review of the literature

Peripheral neuropathy is associated with an increase in intraneural pressure, and hence ultrasound elastography seems to be an ideal method to detect early stages of this condition based on changes in the affected nerve stiffness. The aim of this systematic review was to analyse the applicability of strain elastography (SE) and shear wave elastography (SWE) in the evaluation of peripheral nerves in patients with neuropathy of various aetiologies. Published evidence shows clearly that ultrasound elastography can accurately diagnose many types of peripheral neuropathies (carpal tunnel syndrome and other entrapment neuropathies, diabetic peripheral neuropathy and peripheral neuropathy associated with other systemic diseases), sometimes at the stages at which the condition is still asymptomatic. However, it is still unclear whether elastographic changes within the nerves precede functional anomalies detectable on nerve conduction studies. Also, relatively little is known about the relationship between the stiffness of peripheral nerves and the severity of peripheral neuropathy and its underlying condition. Based on the reproducibility data, SWE seems to be superior to SE. Nevertheless, the sources of heterogeneity in the peripheral nerve stiffness in healthy persons need to be identified, and the sets of reference values for specific peripheral nerves need to be determined. Finally, the potential confounding effect of hardening artefacts, such as bones, on the stiffness of peripheral nerves needs to be verified. After addressing all these issues, elastographic evaluation of peripheral nerve stiffness might become a reliable, easily accessible, and convenient diagnostic test performed routinely in patients with various peripheral neuropathies.

Musculoskeletal hand involvement in systemic sclerosis

Musculoskeletal (MSK) involvement of the hands is a significant source of morbidity, impacting on quality of life in patients with systemic sclerosis (SSc). MSK complications are common in SSc and can affect the whole of the MSK system. MSK hand involvement can occur early in the course of the disease. A wide range of articular involvement is recognised including from arthralgia to inflammatory joint and tendon disease. Mechanistic insights have been made into enthesitis, hand contractures and tendon friction rubs and could inform the development inform novel treatment approaches to MSK involvement in SSc. Bony involvement can include osteomyelitis from digital ulceration. Other important manifestations include (but are not limited to) calcinosis, acro-osteolysis and carpal tunnel syndrome. MSK imaging is an important tool that allows insight into both disease pathogenesis and to inform the clinical management of MSK complications. The purpose of this review is to provide an overview of the MSK hand complications in patients with SSc, highlighting the breadth and burden of pathology relevant to clinical practice.

Quantitative Ultrasound and B-Mode Image Texture Features Correlate with Collagen and Myelin Content in Human Ulnar Nerve Fascicles

We investigate the usefulness of quantitative ultrasound and B-mode texture features for characterization of ulnar nerve fascicles. Ultrasound data were acquired from cadaveric specimens using a nominal 30-MHz probe. Next, the nerves were extracted to prepare histology sections. Eighty-five fascicles were matched between the B-mode images and the histology sections. For each fascicle image, we selected an intra-fascicular region of interest. We used histology sections to determine features related to the concentration of collagen and myelin and ultrasound data to calculate the backscatter coefficient (-24.89 ± 8.31 dB), attenuation coefficient (0.92 ± 0.04 db/cm-MHz), Nakagami parameter (1.01 ± 0.18) and entropy (6.92 ± 0.83), as well as B-mode texture features obtained via the gray-level co-occurrence matrix algorithm. Significant Spearman rank correlations between the combined collagen and myelin concentrations were obtained for the backscatter coefficient (R = -0.68), entropy (R = -0.51) and several texture features. Our study indicates that quantitative ultrasound may potentially provide information on structural components of nerve fascicles.

Basis of Shoulder Nerve Entrapment Syndrome: An Ultrasonographic Study Exploring Factors Influencing Cross-Sectional Area of the Suprascapular Nerve

As changes in nerves' shape and size are common ultrasonographic findings of entrapment neuropathy, measurement of the nerve cross-sectional area (CSA) becomes the mostly used indicator to differentiate normality from pathology. Recently, more US research has been conducted to measure the shape of the suprascapular notch and the diameter of the suprascapular nerve. Because the suprascapular nerve is paramount for various shoulder disorders, the present study aims to establish normal values of suprascapular nerve sizes at different levels as well as to investigate potential influence of participants' characteristics on the CSA measurements. The present study used a cross-sectional design investigating the CSA values of the suprascapular nerve from the supraclavicular region to spinoglenoid notch. We employed the inside-epineurium and outside-epineurium methods to quantify CSA of cervical roots (C5 and C6) and the suprascapular nerve on US imaging. Univariate comparisons of nerve sizes among different age and gender groups were carried out. Multivariate analysis was performed to analyze the impact of participants' characteristics on nerve CSA. Repeated measurement analysis of variance was conducted to examine segmental variations of CSA of the suprascapular nerve from its origin to infraspinatus fossa. Our study included 60 healthy adults with 120 shoulders and had three major findings: (1) the inside-epineurium method was more reliable than the outside-epineurium approach for CSA measurements due to higher intra- and inter-rater reliability, (2) women had smaller sizes for cervical nerve roots and for the most proximal segment of the suprascapular nerves, and (3) using the outside-epineurium method, the suprascapular nerve CSA was larger in its distal division than the portion proximal to the mid-clavicular line. In conclusion, the inside-epineurium method has better reliability for nerve CSA assessment but the outside-epineurium method is needed for quantifying the size of distal suprascapular nerve. Gender difference in CSA values should be considered during evaluation of the most proximal nerve segment. Using the outside-epineurium method, the distal suprascapular nerve would be estimated larger than its proximal portion and the segmental discrepancy should be not misinterpreted as pathology.

Increased stiffness of median nerve in systemic sclerosis

Background

Systemic sclerosis can affect peripheral nerves, but the extent and the nature of this involvement are not well defined. The aim of this study is to compare the sonoelastrographic measurements of median nerves in systemic sclerosis (SSC), idiopathic carpal tunnel syndrome (CTS) and healthy individuals.

Methods

The clinical, electrophysiological and ultrasonographic assessments were done. Patients with SSC and CTS were assessed with nerve conduction studies. The measurements of cross sectional areas (CSA) were performed at psiform and forearm level from axial US images. The elastic ratio is the ratio of strain distribution in two selected region of interests (ROI) done via comparing the median nerve to flexor digitorum superfcialis tendon. The ROIs were fixed to 2 mm.

Results

The study was completed with 47 hands of 24 patients with SSC, 53 hands of 27 patients with CTS and 38 hands of health controls. The CSA of CTS group was significantly higher than systemic sclerosis and control groups. The elastic ratio at psiform level and forearm levels of systemic sclerosis group were significantly higher than the CTS and control groups.

Conclusion

Median nerves lose the elasticity while the CSA’s are in the normal range in patients with SSC. These results suggested that the increased peripheral nerve involvement in SSC is about the increased stiffness of the nerves.

Magnetic resonance and ultrasound in achilles tendinopathy: Predictive role and response assessment to platelet-rich plasma and adipose-derived stromal vascular fraction injection

OBJECTIVE

To assess the correlation between magnetic resonance and ultrasound findings and clinical outcome after intratendinous injection of leucocyte-rich platelet-rich plasma or adipose-derived stromal vascular fraction in patients with non-insertional Achilles tendinopathy.

MATERIALS AND METHODS

Forty-three patients (age: 47.8±5.1, range 29-55) with unilateral or bilateral non-insertional Achilles tendinopathy (58 tendons overall) were randomly assigned to platelet-rich plasma (22 patients, 28 tendons) or adipose-derived stromal vascular fraction (21 patients, 30 tendons) injection group. All patients underwent magnetic resonance (tendon cross-sectional area, signal intensity, maximum anteroposterior thickness were measured), ultrasound (maximum anteroposterior thickness, power Doppler signal, ultrasound gray scale echotexture were measured), and visual analogue scale (VAS) pain evaluation at baseline and at six months from treatment. Wilcoxon, intraclass correlation coefficient, repeated measure ANOVA tests were used.

RESULTS

There was a significant (P<0.001) decrease of mean VAS from pre-treatment (6.4±1.4) to six-month evaluation (1.8±1.7). Significant increase of tendon thickness measured using magnetic resonance (P=0.013) and ultrasound (P=0.012) and power Doppler signal (P=0.027) was seen. There was no significant difference between pre- and post-treatment cross sectional area, signal intensity, and echotexture (P>0.217). None of the pre-treatment parameters was a predictor of treatment outcome (P>0.104). There was an excellent agreement between tendon thickness measurement between magnetic resonance and ultrasound (intraclass correlation coefficient=0.986) CONCLUSIONS: Both treatments seem to allow for clinical benefit, associated to early slight increase of tendon size and power Doppler signal. Imaging cannot be used as a predictor of clinical outcome.