Shear Wave and Strain Elastographic Features of the Brachial Plexus in Healthy Adults: Reliability of the Findings-a Pilot Study

Evaluation of brachial plexus stiffness in different arm and head positions by sonoelastography

Intraoperative positioning-related nerve injuries, particularly those affecting the brachial plexus, are concerning complications believed to arise from stretching and/or compression of peripheral nerves. Although sonoelastography, a new ultrasound technology, is emerging as a valuable tool in the musculoskeletal system, its utility in evaluating peripheral nerves remains unclear. This study aimed to utilize sonoelastography to assess the brachial plexus during surgery, specifically investigating changes in its stiffness values in relation to different head and arm positions. In this prospective cohort study, bilateral brachial plexuses of 8 volunteers in 3 different positions were enrolled. Using a high-frequency linear probe, the stiffness of the brachial plexus was quantitatively measured in kilopascals (kPa) under 3 different positions: neutral, head rotated, and head rotated with arm hyperabducted. Intra-class agreement was evaluated. The stiffness of the brachial plexus was 7.39 kPa in the neutral position (NP), 10.28 kPa with head rotation, and 17.24 kPa when the head was turned, and the ipsilateral arm was hyperabducted. Significant increases were observed in stiffness values when the head was turned, whether ipsilaterally or contralaterally, and during hyperabduction of the arm while the head was turned (for all P < .001). Strong intra-class correlations were found for the measurements of stiffness values (ICC = 0.988-0.989; P < .001; Cronbach Alpha = 0.987-0.989). Sonoelastography revealed significant increases in the stiffness of the brachial plexus with various head rotations and arm positions compared to the neutral state. These findings suggest that sonoelastography could potentially serve as a valuable tool for assessing the risk of brachial plexus injury during surgery and for guiding optimal patient positioning. Further research with larger sample sizes is needed to establish definitive clinical applications.

Interobserver and Intraobserver Reliability in Sonoelastographic Assessment of Thyroid Nodules

BACKGROUND

Thyroid ultrasonography is the first and perhaps most fundamental step for the radiological distinction of benign and malignant nodules. In this study, 2 radiologists reviewed the sonoelastographic and Doppler images of thyroid nodules and evaluated for the intraobserver and interobserver reliability.

PURPOSE

We aimed to determine confusing nodule identifiers and sonographic features differently defined by observers.

METHODS

A total of 157 nodules in 91 patients (male/female, 72:19) with ages ranging from 18 to 72 years old were included in the study. Ultrasonographic images and video clips of the nodules were obtained and presented to 2 reviewers unaware of the cytopathology results. Two observers defined the characteristics of the nodules based on previously determined criteria. Then, intraobserver and interobserver correlation coefficients were calculated for each subcategory.

RESULTS

In the grayscale ultrasonographic examination, varying degrees from low to high interobserver correlation coefficients were obtained for different subcategories (between κ = 0.359 and κ = 0.821). In color Doppler examination, we obtained medium correlation coefficients ( κ = 0.493 and κ = 0.553). On the other hand, there was a high correlation coefficient in tissue compression elastography ( κ = 0.617 and κ = 0.638).According to our study results, elastographic pattern, shape of the nodule, presence of echogenic foci, and pathological lymph nodes are better predictors to determine the malignant potential of thyroid nodule with higher interobserver correlation. Therefore, these criteria may be used primarily for the evaluation of thyroid nodules. The intraobserver correlation coefficient was higher in the practitioner with longer experience, suggesting the importance of professional practice period on the decision-making process.

Quantitative shear wave elastography assessment of tibial nerve in diagnosis of diabetic peripheral neuropathy

Background

Diabetic peripheral neuropathy (DPN) is one of the most common complications of diabetes mellitus. Diagnosis of DPN is very important in the prognosis of disease and treatment as early treatment of DPN decreases both short-term and long-term morbidities. SWE elastography is a noninvasive and reproducible method for the precise evaluation of nerve stiffness.

Results

Tibial nerve stiffness is notably high at SWE in diabetic patients with DPN (mean shear wave elastography value of RT tibial SWE 75.3 ± 15.1 kPa) compared to patients without DPN (mean shear wave elastography value of RT tibial SWE 37.8 ± 11.6 kPa) and nerve stiffness in healthy control subjects (mean shear wave elastography value of RT tibial SWE 24.9 ± 6.3 kPa). There is a significant increase in the cross-sectional area (CSA) among diabetic patients with DPN (mean cross-sectional area of the right tibial nerve of 17 ± 1.9 mm2) and without DPN (mean cross-sectional area of the right tibial nerve of 14.5 ± 3.8 mm2) in comparison with control subjects (mean cross-sectional area of the right tibial nerve of 13.2 ± 3.1 mm2) in the right side. Borderline significance of the CSA parameters of the tibial nerve study on the left side in different groups. The cutoff point to determine DPN among diabetic patients in the right lower limb is more than 63.8 kPa. With 89% sensitivity and 100% specificity in the detection of DPN on the right side, the SWE has 100% PPV and 95.5% NPV in the detection of DPN on the right side.

Conclusion

SWE is an effective assistant method in the diagnosis of DPN and is useful when a suspected neuropathy is not detectable by electrophysiology.

Strain and shearwave sonoelastographic findings of quadriceps tendon in patients with chronic kidney disease. Are they reliable?

AIM

In this study, we aimed to compare the strain (SE) and shear wave elastography (SWE) findings of the quadriceps tendons (QT) of the patients with chronic kidney disease (CKD) and healthy volunteers (HV), and estimate the reliability of the evaluations.

MATERIALS AND METHODS

Twenty-nine HV and twenty-seven patients with CKD were enrolled. All sonoelastographic examinations were performed separately by two observers. The QT thickness (QTT), SWE, and SE findings including the tissue elastic modulus (EM), shear wave velocity (SWV), and the elasticity patterns were obtained and compared. Interobserver agreement was evaluated to test the reliability of the findings.

RESULTS

The QT in CKD patients is thinner than HV (p = 0.001 for both observers). The elasticity patterns of QT were mostly intermediate stiffness for both observers (p < 0.05 for both observers). The mean EM values in the patient group were significantly higher than HV for both observers (p < 0.05 for both observers). The mean SWVs were significantly higher in the patient group (p < 0.05 for both observers). SWV showed weak, significant, and negative correlations with the hemodialysis (HD) duration (p < 0.05 for both observers). The interobserver agreements were moderate to excellent for QTT, EM, SWS, and SE patterns (p < 0.01 for all parameters).

CONCLUSION

QTT and its elasticity are decreased in patients with CKD. The QTT and SE patterns may be the choice to determine the elasticity in CKD patients with good reliability values rather than SWE. But, there is still debate on the reliability of sonoelastographic findings, to ensure standardization of the factors affecting reliability, they should be well understood.

Shear wave elastography evaluation of brachial plexus in multiple sclerosis

BACKGROUND

Multiple sclerosis (MS) is a chronic neuroinflammatory disease characterized by inflammation involving the peripheral nerves. Shear wave elastography (SWE) is potentially a method of choice for detecting peripheral nerve involvement.

PURPOSE

To compare the degree of thickening and nerve elasticity of brachial plexus (BP) nerve roots and evaluate the usefulness of sonoelastography in patients with clinically diagnosed MS without brachial plexopathy.

MATERIAL AND METHODS

Thirty-two patients with MS and 32 controls were included in the study. Bilateral C5, C6, and C7 mean nerve root diameters, and mean elasticity values in kiloPascal (kPa) were measured in the patient and control groups. The relationship between the age, height, and weight values and nerve diameter-elasticity values of the patient and control groups was compared.

RESULTS

The elasticity values of the C5 and C6 nerve roots were increased, and the nerve root thickness was decreased in the MS group compared to that in the control (P < 0.05). There was no difference between the C7 mean nerve root elasticity (kPa) and diameter measurements in the patient and control groups (P > 0.05).

CONCLUSION

Our study showed an increase in the BP nerve root elasticity values (kPa) in patients with MS compared to that of the control group and a decrease in diameter values thought to be related to the possible chronic atrophic process. The results are consistent with the demyelinating process of the peripheral nervous system (PNS) due to MS.

A preliminary animal study on the prediction of nerve block success using ultrasonographic parameters

This study aimed to evaluate the diagnostic value of ultrasonographic parameters as an indicator for predicting regional nerve block success. Ultrasound-guided sciatic nerve block was performed in seven dogs using either 2% mepivacaine (nerve-block group) or saline (sham-block group). The cross-sectional area (CSA), nerve blood flow (NBF), and shear wave velocity (SWV) of the sciatic nerve (SWVN), SWV of the biceps femoris muscle (SWVM), and their ratio (SWVNMR) were measured at 0, 30, 60, and 90 min after the nerve block as well as the change rate of each parameter from the baseline. A receiver operating characteristic (ROC) curve analysis was performed to determine the diagnostic value of each parameter in the prediction of nerve block success. No significant changes were observed in the CSA or NBF in association with the nerve block. The SWVN and SWVNMR in the nerve-block group were significantly higher than those in the sham-block group at 90 min and at 30, 60, and 90 min, respectively (p < 0.05). The change rates of SWVN and SWVNMR in the nerve-block group were significantly higher than those in the sham-block group at all time points (p < 0.05). The ROC curve analysis showed that SWVN had a moderate diagnostic accuracy (area under the curve [AUC], 0.779), whereas SWVNMR and change rates of SWVN and SWVNMR had a high diagnostic accuracy (AUC, 0.947, 0.998, and 1.000, respectively). Ultrasonographic evaluation of the SWVN and SWVNMR could be used as indicators for predicting nerve block success.

Shear wave elastography of the tibial nerve in healthy subjects

The purpose of this study is to investigate sonoelastographic features of the tibial nerve.The study included 72 tibial nerves in 36 healthy subjects. High resolution ultrasound and Shear wave elastography were used to evaluate the tibial nerve. Cross sectional area and stiffness were measured.The mean cross sectional area of the tibial nerve was 13.4 mm2. The mean shear elastic modulus of the tibial nerve in the short axis was 23.3 kPa. The mean shear elastic modulus of the tibial nerve in long axis was 26.1 kPa. The tibial nerve elastic modulus also showed no correlation with cross sectional area neither in the long axis nor short axis. Age, height, weight, and body mass index showed no correlation with tibial nerve elastic modulus in short or long axes.The elastic modulus of the tibial nerve has been determined in healthy subjects and can serve as a reference for future assessment of polyneuropathy.

Shear wave elastography of the saphenous nerve

The purpose of this study is to study sonoelastographic features of the saphenous nerve.The study included 72 saphenous nerves in 36 healthy subjects. High resolution ultrasound and Shearwave elastography were used to evaluate the saphenous nerve. Cross sectional area (CSA) and stiffness were measured.The mean CSA of the saphenous nerve was 5.7 mm. The mean shear elastic modulus of the saphenous nerve in the short axis was 29.5 kPa. The mean shear elastic modulus of the saphenous nerve in long axis was 29.9 kPa. The saphenous nerve elastic modulus also showed no correlation with CSA in neither the long axis nor short axis. Positive correlation between elasticity measurements in the long and short axes. Age, height, weight, and BMI showed no correlation with saphenous nerve elastic modulus in short or long axes.The elastic modulus of the saphenous nerve has been determined in healthy subjects and can serve as a reference for future assessment of the saphenous nerve before different procedures.

Utility of Ultrasound Elastography in Evaluation of Carpal Tunnel Syndrome: A Systematic Review and Meta-analysis

We systematically reviewed observational studies investigating ultrasound elastography for median nerves in the carpal tunnel syndrome (CTS) population. PubMed and Embase were studied from the earliest record to April 2019. The primary outcome was the comparison of elasticity of the median nerve between participants with and without CTS, quantified by the standardized mean difference (SMD) and its 95% confidence interval. The median nerve is considered to be stiffer in the CTS population when the SMD of tissue strain is negative, or that of strain ratio, shear modulus and shear wave velocity are positive. The present meta-analysis included 17 studies, evaluating 1401 wrists. Our result showed that regardless of the ultrasound elastography mode (tissue strain, strain ratio, shear modulus and shear wave velocity) used, median nerves at the wrist level in patients with CTS were consistently stiffer than those in healthy controls. Importantly, ultrasound elastography revealed its potential in differentiating CTS of different severity.

Ultrasound elastography for the evaluation of peripheral nerves: A systematic review

Peripheral nerve disorders are commonly encountered in clinical practice. Electrodiagnostic studies remain the cornerstone of the evaluation of nerve disorders. More recently, ultrasound has played an increasing complementary role in the neuromuscular clinic. Ultrasound elastography is a technique that measures the elastic properties of tissues. Given the histological changes that occur in diseased peripheral nerves, nerve ultrasound elastography has been explored as a noninvasive way to evaluate changes in nerve tissue composition. Studies to date suggest that nerve stiffness tends to increase in the setting of peripheral neuropathy, regardless of etiology, consistent with loss of more compliant myelin, and replacement with connective tissue. The aim of this systematic review is to summarize the current literature on the use of ultrasound elastography in the evaluation of peripheral neuropathy. Limitations of ultrasound elastography and gaps in current literature are discussed, and prospects for future clinical and research applications are raised.

Assessment of Peripheral Nerves With Shear Wave Elastography in Type 1 Diabetic Adolescents Without Diabetic Peripheral Neuropathy

OBJECTIVES

To investigate the utility of shear wave elastography (SWE) in detecting morphologic abnormalities of the median nerve and posterior tibial nerve in transverse and longitudinal axes in adolescents with type 1 diabetes mellitus (DM) without diabetic peripheral neuropathy (DPN).

METHODS

The median nerves and posterior tibial nerves of 25 adolescents with diagnosis and follow-up of type 1 DM without DPN and 32 healthy volunteers were evaluated with SWE by 2 observers on the transverse and longitudinal axes. The cross-sectional area and thickness of the nerves and disease duration were noted, and probable associations of these parameters with SWE features were analyzed. Interobserver and intraobserver correlations were also examined. The statistical significance level was set at P < .05.

RESULTS

Both the median nerve and posterior tibial nerve were smaller, thinner, and stiffer in the patient group for both observers on both axes. The disease duration weakly correlated with median nerve SWE features (r = 0.245-0391). The thickness and cross-sectional area had no correlations with SWE features.

CONCLUSIONS

The median nerve and posterior tibial nerve in adolescents with type 1 DM without DPN have morphologic abnormalities that can be displayed by SWE regardless of the imaging axis. Shear wave elastography may have a potential role in subclinical DPN, but the reliability of the findings is not as high as desirable.