Morphological changes of the peripheral nerves evaluated by high-resolution ultrasonography are associated with the severity of diabetic neuropathy, but not corneal nerve fiber pathology in patients with type 2 diabetes

Nerve ultrasound helps to distinguish CIDP patients with diabetes from patients with diabetic polyneuropathy

Diabetic polyneuropathy (DPN) shares overlapping clinical and electrodiagnostic features with chronic inflammatory demyelinating polyneuropathy (CIDP), which complicates the differential diagnosis of CIDP in diabetic patients. 32 patients with diabetes mellitus and CIDP, 68 patients with CIDP without diabetes, 83 patients with DPN, and 28 diabetic patients without polyneuropathy were examined using clinical scores (Overall Neuropathy Limitation Scale (ONLS), Neuropathy Symptom Score, Neuropathy Deficit Score), nerve conduction studies, and nerve ultrasound (Ultrasound Pattern Sum Score (UPSS)). The ONLS was significantly higher in the CIDP patients with diabetes than in DPN (median [interquartile range]: 4.0 [3.0] vs. 0 [1.0], p < 0.001) as well as the UPSS (4.0 [6.0] vs. 0 [2.9], p < 0.001). Multiple binary logistic regression revealed UPSS and ONLS as statistically significant predictors to differentiate between CIDP with diabetes and DPN. Receiver operating characteristic curve analysis showed the ONLS with an area under the curve (AUC) of 0.918 (95% CI: 0.868-0.0.967, p < 0.001). The UPSS total score had an AUC of 0.826 (95% CI: 0.743-0.909, p < 0.001). An UPSS ≥ 2.5 had a sensitivity of 77.4% and a specificity of 68.7% to detect CIDP. An ONLS ≥ 1.5 had a sensitivity of 87.1% and a specificity of 81.9% to detect CIDP. ROC curve analysis of a composite score of ONLS and UPSS revealed an AUC of 0.959 (95% CI: 0.928-0.991, p < 0.001). CIDP is an important differential diagnosis in people with diabetes mellitus. This study reports that the UPSS is well suited to differentiate between DPN and CIDP.

Cut-off value for a normal posterior tibial nerve to diagnose tarsal tunnel syndrome amongst people of different race in Pretoria, South Africa

INTRODUCTION

Posterior tibial nerve (PTN) cross-sectional area (CSA) reference values for the diagnosis of tarsal tunnel syndrome (TTS) using ultrasound imaging exist in several countries but not in South Africa (SA). Therefore, the objective was to measure the CSA reference values for PTN in SA.

METHODS

Ultrasound CSA measurements of PTN in both ankles on 112 participants were performed, the mean measurement was recorded, and the effect of race, age, gender, and body mass index (BMI) were recorded.

RESULTS

In this study, the primary variables age and BMI affect the CSA measurement of the PTN. A positive correlation was found between PTN asymptomatic size and age (r = 0.196, P < 0.05), size and BMI (r = 0.200, P < 0.05). Age (categories) had a mean value of 3.17 for the age group 36-45 years (95% confidence interval (CI) 2.9-3.4). The mean BMI was 30.0 kg/m2 (CI 28.57-31.08). As for the asymptomatic PTN, a mean CSA reference value of 0.10 cm2 was obtained.

CONCLUSION

With increase in age and BMI, a greater PTN measurement will occur. Race appears to be a contributing factor, but further research is needed in this regard. The reference CSA value for normal PTN should be set at 0.10 cm2 for all racial groups for a basic musculoskeletal ultrasound exam protocol in South Africa.

Morphometry of the sural nerve in diabetic neuropathy: a systematic review

PURPOSE

The aim of this systematic review is to evaluate the usefulness of sural nerve ultrasonography in diagnosing diabetes mellitus (DM) and diabetic polyneuropathy (DPN), the latter of which is a common long-term complication for diabetic patients that frequently involves the sural nerve.

METHODOLOGY

A meta-analysis of the cross-sectional areas (CSAs) of sural nerves in healthy individuals and patients with diabetes mellitus based on a total of 32 ultrasonographic-based studies from 2015 to 2023 was performed. Sub-analyses were performed for factors such as geographical location and measurement site.

RESULTS

The meta-analysis showed that the mean CSA of the sural nerve was significantly larger in DM patients with DPN only compared to healthy individuals across all regions and when pooled together. An age-dependent increase in the CSA of healthy sural nerves is apparent when comparing the paediatric population with adults.

CONCLUSION

Sural nerve ultrasonography can distinguish diabetic adults with DPN from healthy adults based on cross-sectional area measurement. Future studies are needed to clarify the relationships between other parameters, such as body metrics and age, with sural nerve CSAs. Cut-offs for DPN likely need to be specific for different geographical regions.

Posterior Tibial Nerve Ultrasound Assessment of Peripheral Neuropathy in Adults with Type 2 Diabetes Mellitus

Background

Diabetic peripheral neuropathy (DPN) is a common and debilitating complication of type 2 diabetes mellitus (T2DM). Early detection and prompt institution of appropriate therapy could prevent undesirable outcomes such as paresthesia, pain, and amputation. Although the gold standard for diagnosing DPN is nerve conduction studies, high-resolution peripheral nerve ultrasonography may serve as a noninvasive and low-cost alternative for diagnosing and staging DPN. This study investigated the clinical utility of sonographic posterior tibial nerve cross-sectional area (PTN CSA) for diagnosing DPN in individuals with T2DM.

Methods

Eighty consecutive adults with T2DM and 80 age-/sex-matched controls were recruited. Clinical information was obtained, including symptoms, disease duration, Toronto clinical neuropathy score (TCNS), and biochemical parameters. The left PTN CSA at 1 cm, 3 cm, and 5 cm above the medial malleolus (MM) was measured with a high-frequency ultrasound transducer and compared to the detection of DPN using the TCNS.

Results

Based on the TCNS, 58 (72.5%) of the T2DM group had DPN. Of these, 14 (24.1%), 16 (27.6%), and 28 (48.3%) participants had mild, moderate, and severe DPN, respectively. All the mean PTN CSA (aggregate, 1 cm, 3 cm, and 5 cm above MM) of the participants with T2DM and DPN (T2DM-DPN) were significantly higher than those of T2DM without DPN (WDPN) and controls. All the PTN CSA increased significantly with increasing severity of DPN. The PTN CSA at 3 and 5 cm levels correlated weakly but significantly with fasting plasma glucose and glycated hemoglobin levels.

Conclusion

The PTN CSA is significantly larger in T2DM-DPN than in T2DM-WDPN and healthy controls. PTN ultrasonography can be an additional tool for screening DPN in patients with T2DM.

Nerve ultrasonographic findings in diabetes mellitus are determined by anatomical location and type of diabetes

Objective

A prospective ultrasound study to analyze nerve size and its modifying factors in type 1 and type 2 diabetes mellitus.

Methods

The cross-sectional areas (CSAs) of motor and sensory nerves in both upper and lower limbs were measured at 14 measurement points, using high resolution ultrasound in 26 patients with type 1 and 76 patients with type 2 diabetes, and in 50 control subjects. All diabetic patients underwent electrophysiological assessment to check for the presence of polyneuropathy.

Results

Significant mild/moderate diffuse nerve enlargement was demonstrated in type 2 diabetes, more pronounced at compression sites versus non-compression sites, and on the upper limbs versus lower limbs (p value for pooled DM2 v. control group: <0.001). In type 1 diabetes, nerve enlargement was found only at one compression site (median nerve wrist; p = 0.002). No significant difference was found between patients with or without polyneuropathy.

Conclusions

The primary predictors of nerve size in diabetes are anatomical location (i.e. compression sites versus non-compression sites, upper versus lower limbs) and type of diabetes. Changes occur before the electrophysiological signs of polyneuropathy are detected.

Significance

Nerve ultrasound may contribute to early recognition of the neuropathic complications of diabetes.

Corneal confocal microscopy for the diagnosis of diabetic peripheral neuropathy: A systematic review and meta-analysis

INTRODUCTION

Corneal confocal microscopy (CCM) is a rapid non-invasive ophthalmic imaging technique that identifies corneal nerve fiber damage. Small studies suggest that CCM could be used to assess patients with diabetic peripheral neuropathy (DPN).

AIM

To undertake a systematic review and meta-analysis assessing the diagnostic utility of CCM for sub-clinical DPN (DPN- ) and established DPN (DPN+ ).

DATA SOURCES

Databases (PubMed, Embase, Central, ProQuest) were searched for studies using CCM in patients with diabetes up to April 2020.

STUDY SELECTION

Studies were included if they reported on at least one CCM parameter in patients with diabetes.

DATA EXTRACTION

Corneal nerve fiber density (CNFD), corneal nerve branch density (CNBD), corneal nerve fiber length (CNFL), and inferior whorl length (IWL) were compared between patients with diabetes with and without DPN and controls. Meta-analysis was undertaken using RevMan V.5.3.

DATA SYNTHESIS

Thirty-eight studies including ~4,000 participants were included in this meta-analysis. There were significant reductions in CNFD, CNBD, CNFL, and IWL in DPN- vs controls (P < 0.00001), DPN+ vs controls (P < 0.00001), and DPN+ vs DPN- (P < 0.00001).

CONCLUSION

This systematic review and meta-analysis shows that CCM detects small nerve fiber loss in subclinical and clinical DPN and concludes that CCM has good diagnostic utility in DPN.

Ultrasound evaluation of peripheral nerves of the lower limb in diabetic peripheral neuropathy

PURPOSE

Comparative evaluation of the cross-sectional area (CSA) of the sural and tibial nerves using ultrasound in diabetic peripheral neuropathy (DPN).

METHOD

This study involved 210 participants divided into 3 groups: type 2 diabetics with DPN, type 2 diabetics without DPN, and controls. Ultrasound evaluation of the sural and tibial nerves was done using a 5-17 MHz linear transducer. The CSA of both the nerves was recorded in both lower limbs. Nerve conduction studies (NCS) were also done in all diabetic patients.

RESULTS

There were 70 participants in each group. All the three groups were gender-matched and no significant difference was observed between CSA values of the sural and tibial nerves between males and females and also in right and left lower limbs within a group. The sural nerve CSA was significantly higher in the DPN group than in diabetic patients without DPN and controls. The sensitivity of the sural nerve CSA was higher than the tibial nerve with a cut-off value of 4.41 mm² for CSA of the sural nerve.

CONCLUSION

The sural nerve CSA at the superior border of lateral malleolus can be used for screening DPN. With well-established cut-off values may result in early initiation of the therapy even in NCS negative cases, thus reducing the morbidity associated with the disease. Ultrasound could be used as a first diagnostic tool for detection of DPN which can be followed by NCS in cases where ultrasound is non-diagnostic.

Effect of massage, passive neural mobilization and transcutaneous electrical nerve stimulation on magnetic resonance diffusion tensor imaging (MR-DTI) of the tibial nerve in a patient with type 2 diabetes mellitus induced neuropathy: a case report

BACKGROUND

MR-DTI parameters namely fractional anisotropy (FA) and apparent diffusion coefficient values (ADC) of diffusion imaging demonstrate the directional preference and speed of diffusion of water molecules. The purpose of this case report is to explore the effect of massage, passive neural mobilization and transcutaneous electrical nerve stimulation on MR-DTI of the tibial nerve in a patient with type 2 diabetes mellitus having chronic distal symmetrical sensorimotor neuropathy.

CASE DESCRIPTION

A 63-year-old male with type 2 diabetes mellitus diagnosed with chronic symmetrical sensorimotor diabetic peripheral neuropathy on the basis of medical examination and electrophysiological testing. Altered mechanosensitivity of the tibial nerve was confirmed through neurodynamic testing. MR-DTI revealed severe damage of the tibial nerve as shown by chaotic diffusion of water molecules and damaged microstructural integrity.

INTERVENTION

A total six sessions over 3 weeks including nerve massage in a longitudinal and transverse direction; passive neural mobilization consisting of sliders and tensioners of the tibial nerve; and followed by 15 minutes of continuous transcutaneous electrical nerve stimulation directed along the nerve course.

OUTCOME

FA and ADC values, pain,neuropathy quality of life and range of motion data were collected pre and post intervention. Analysis revealed clinical improvement in all the outcome measures.

CONCLUSION

This case report identified improvement in radiological MR-DTI outcomes following rehabilitation in a patient with diabetic peripheral neuropathy.

Gold Standard for Diagnosis of DPN

Diabetic peripheral neuropathy (DPN) is a common complication of diabetes mellitus. It often causes symmetrical paresthesia, loss of sensation, and hyperalgesia. Without early intervention, it might lead to diabetic foot ulceration, gangrene, and subsequent amputation in people with diabetes. DPN is an insidious disease and often underdiagnosed. This paper reviews the current national and international prevalence of DPN, screening methods for early DPN, including quantitative sensory measurement, neurological function scoring system, confocal microscopy, and high-frequency ultrasound, and summarizes the related research progress, clinical application, and development prospects of these methods in recent years.

High resolution ultrasound in subclinical diabetic neuropathy: A potential screening tool

Introduction

Detection of subclinical neuropathy can aid in triage, timely intervention and dedicated care to reduce disease progression and morbidity. High resolution sonography has emerged as a promising technique for evaluation of peripheral nerves. The aim of the present study was to assess the utility of high resolution sonography in screening diabetic patients for subclinical neuropathy.

Methods

A total of 70 adult patients with type 2 diabetes mellitus and 30 controls were enrolled; those with clinical features of neuropathy constituted the diabetic polyneuropathy group and those without symptoms/normal nerve conduction the non-diabetic polyneuropathy group. After institutional ethical committee approval and informed consent, high resolution sonography was performed by two musculoskeletal radiologists. Nerves studied were median (elbow and wrist), ulnar (cubital tunnel and Guyon's canal), common peroneal (fibular head) and posterior tibial nerve (medial malleolus).The size (cross sectional area), shape, echogenicity and morphology of nerve were assessed and compared between the groups.

Results

The mean cross sectional area of all nerves was significantly higher both in diabetic polyneuropathy and non-diabetic polyneuropathy group compared to controls (p value < .001). Common peroneal nerve cross sectional area of 4.5 mm² had the highest sensitivity (93%) and specificity (86%) for detecting nerve changes in the non-diabetic polyneuropathy group. The nerves were more rounded, hypoechoic and had an altered morphology in both study groups.

Conclusion

Presence of sonographic nerve changes in asymptomatic diabetics depicted that morphological alterations in nerves precede clinical symptoms. High resolution sonography detected nerve changes with a good accuracy, and thus, can be a potential screening tool for detection of subclinical diabetic polyneuropathy.

In vivo confocal microscopy study of corneal nerve alterations in children and youths with Type 1 diabetes

OBJECTIVE

To determine whether children and youths with Type 1 diabetes (T1D) have early alterations of the corneal subbasal nerve plexus detectable with in vivo confocal microscopy (IVCM) and to investigate the role of longitudinally measured major risk factors for diabetes complications associated with these alterations.

METHODS

One hundred and fifty children and youths with T1D and 51 age-matched controls were enrolled and underwent IVCM. Corneal nerve fiber length (CNFL), corneal nerve fiber density (CNFD), corneal nerve branch density (CNBD), corneal fiber total branch density (CTBD), and corneal fiber fractal dimension (CNFrD) were measured. Risk factors for diabetes complications (blood pressure, BMI, HbA1c, lipoproteins, urinary albumin-creatinine ratio) were recorded at IVCM and longitudinally since T1D onset. Unpaired t-test was used to compare variables between the groups. Multiple regression models were calculated using IVCM parameters as dependent variables and risk factors as independent variables.

RESULTS

All IVCM parameters, except CTBD, were significantly lower in the T1D patients. Glycometabolic control (HbA1c, visit-to-visit HbA1c variability, and mean HbA1c), and blood pressure were inversely correlated with IVCM parameters. Multiple regression showed that part of the variability in CNFL, CNFD, CTBD, and CNFraD was explained by HbA1c, blood pressure percentiles and age at IVCM examination, independent of diabetes duration, BMI percentile and LDL cholesterol. Comparable results were obtained using the mean value of risk factors measured longitudinally since T1D onset.

CONCLUSIONS

Early signs of corneal nerve degeneration were found in children and youths with T1D. Glycometabolic control and blood pressure were the major risk factors for these alterations.

High resolution ultrasonography of peripheral nerves in diabetic patients to evaluate nerve cross sectional area with clinical profile

OBJECTIVES

The aim of this observational study was ultrasound evaluation of peripheral nerves cross-sectional area (CSA) in subjects with probable diabetic peripheral sensorimotor neuropathy (DPN). CSA was analyzed with reference to clinical and nerve conduction study's (NCS) parameters for early diagnosis and pattern of involvement.

METHODS

A total of 50 patients with probable DPN due to Type 2 diabetes and 50 age-matched healthy controls underwent sonographic examinations of ulnar nerve at the lower arm, median nerve proximal to carpal tunnel, the common peroneal nerve proximal to fibular head, tibial nerve proximal to the tarsal tunnel, and sural nerve at lower third leg.

RESULTS

CSA was increased in cases of DPN as compared to healthy controls. Area changes were more marked with demyelinating pattern. Probable DPN cases with normal NCS had significantly higher number of peripheral nerves showing increased CSA as compared to healthy control. A cut-off of >4 nerve thickening showed a sensitivity of 86 %, and specificity of 56%. The neuropathy pattern in the lower limb was axonal, whereas in the upper limb, it was demyelinating with the majority showing sonographic feature of associated compressive neuropathy.

CONCLUSION

There is an increase in CSA of peripheral nerve in diabetic patients. It can be used as a morphological marker for classifying DPN with changes being picked up earlier to NCS abnormality. Clinical neurological presentation in probable DPN can also be due to compressive neuropathy in early phases, and ultrasound can be a useful tool.

ADVANCES IN KNOWLEDGE

Early pick up of DPN cases shall be useful for early therapy and motivating the patients to actively participate in the treatment. Morphological changes on ultrasonography precedes the electrodiagnostic change in DPN. Symptoms of DPN is not only due to metabolic changes but also compressive neuropathy.

Application of High-Resolution Ultrasound on Diagnosing Diabetic Peripheral Neuropathy

Diabetic peripheral neuropathy (DPN) is a common complication of diabetes mellitus (DM). The typical manifestation is a length-dependent "glove and sock" sensation. At present, diagnosis is mainly dependent on clinical manifestations. Since the pathogenesis is not clear, there are no effective treatment measures. Management consists mainly of glucose control, peripheral nerve nutrition, and other measures to delay the progress of the disease; early diagnosis is therefore crucial to improving prognosis and quality of life for patients with DPN. Due to the lack of obvious symptoms in 50% of patients and the low sensitivity of neuro-electrophysiology to small fibers, the missed diagnosis rate is high. High-resolution ultrasound (HRU), as a convenient noninvasive tool, has been proven by many studies to have excellent clinical value in diagnosing DPN. With the development of related new technology, HRU shows promise for the screening, diagnosing, and follow-up of DPN, which could serve as a biomarker and provide new diagnostic insights. In this paper, we review the ability of HRU to detect nerve cross-sectional area and blood flow, and echo and other image changes, and in showing the characteristics of peripheral nerve morphological changes in patients with DPN. We also explore the application of two other recent technological developments-shear wave elastography (SWE) and ultrasound scoring systems-in improving the diagnostic efficiency of HRU in peripheral neuropathy.

Corneal nerves in diabetes-The role of the in vivo corneal confocal microscopy of the subbasal nerve plexus in the assessment of peripheral small fiber neuropathy

The cornea's intense innervation is responsible for corneal trophism and ocular surface hemostasis maintenance. Corneal diabetic neuropathy affects subbasal nerve plexus, with progressive alteration of nerves' morphology and density. The quantitative analysis of nerve fibers can be performed with in vivo corneal confocal microscopy considering the main parameters such as corneal nerve fibers length, corneal nerve fibers density, corneal nerve branching density, tortuosity coefficient, and beadings frequency. As the nerve examination permits the detection of early changes occurring in diabetes, the invivo corneal confocal microscopy becomes, over time, an important tool for diabetic polyneuropathy assessment and follow-up. In this review, we summarize the actual evidence about corneal nerve changes in diabetes and the relationship between the grade of alterations and the duration and severity of the disease. We aim at understanding how diabetes impacts corneal nerves and how it correlates with sensorimotor peripheral polyneuropathy and retinal complications. We also attempt to analyze the safety of the most common surgical procedures such as cataract and refractive surgery in diabetic patients and to highlight the specific risk factors. We believe that information about the corneal nerve fibers' condition obtained from the in vivo subbasal nerve plexus investigation may be crucial in monitoring peripheral small fiber polyneuropathy and that it will help with decision-making in ophthalmic surgery in diabetic patients.

Application value of conventional ultrasound and real-time shear wave elastography in patients with type 2 diabetic polyneuropathy

PURPOSE

To explore the application value of conventional ultrasound and real-time shear wave elastography (SWE) to the tibial nerve (TN) and the common peroneal nerve (CPN) in diabetic peripheral neuropathy (DPN).

MATERIALS AND METHODS

Thirty-three healthy volunteers, 33 diabetic patients without DPN, and 30 diabetic patients with DPN were enrolled in this study. The anteroposterior diameter (APD), the cross-sectional area (CSA), and the perimeter of the TN and the CPN were measured by conventional ultrasound, and the stiffness of the nerves was measured by SWE.

RESULTS

The conventional ultrasound parameters and stiffness of the TN in patients with DPN were significantly larger than those of the other two groups (P < 0.01). The conventional ultrasound parameters of the CPN were significantly higher in patients with DPN than in the other two groups (P < 0.01).The patients with DPN demonstrated a greater stiffness of the CPN compared to the control group (P < 0.05). The comparison of all parameters for the left and right TNs and CPNs among the three groups showed no significant difference. The area under the curve (AUC) of TN stiffness for the diagnosis of DPN was significantly greater than that of conventional ultrasound parameters.

CONCLUSION

The conventional ultrasound parameters and the stiffness of the TN and the CPN were significantly higher in patients with DPN. The stiffness of the TN could better diagnose DPN than conventional ultrasound parameters. In short, conventional ultrasound and SWE of nerves are of good application value in the diagnosis of DPN.

Lumos for the long trail: Strategies for clinical diagnosis and severity staging for diabetic polyneuropathy and future directions

Diabetic polyneuropathy, which is a chronic symmetrical length-dependent sensorimotor polyneuropathy, is the most common form of diabetic neuropathy. Although diabetic polyneuropathy is the most important risk factor in cases of diabetic foot, given its poor prognosis, the criteria for diagnosis and staging of diabetic polyneuropathy has not been established; consequently, no disease-modifying treatment is available. Most criteria and scoring systems that were previously proposed consist of clinical signs, symptoms and quantitative examinations, including sensory function tests and nerve conduction study. However, in diabetic polyneuropathy, clinical symptoms, including numbness, pain and allodynia, show no significant correlation with the development of pathophysiological changes in the peripheral nervous system. Therefore, these proposed criteria and scoring systems have failed to become a universal clinical end-point for large-scale clinical trials evaluating the prognosis in diabetes patients. We should use quantitative examinations of which validity has been proven. Nerve conduction study, for example, has been proven effective to evaluate dysfunctions of large nerve fibers. Baba's classification, which uses a nerve conduction study, is one of the most promising diagnostic methods. Loss of small nerve fibers can be determined using corneal confocal microscopy and intra-epidermal nerve fiber density. However, no staging criteria have been proposed using these quantitative evaluations for small fiber neuropathy. To establish a novel diagnostic and staging criteria of diabetic polyneuropathy, we propose three principles to be considered: (i) include only generalizable objective quantitative tests; (ii) exclude clinical symptoms and signs; and (iii) do not restrictively exclude other causes of polyneuropathy.

Structural Nerve Remodeling at 3-T MR Neurography Differs between Painful and Painless Diabetic Polyneuropathy in Type 1 or 2 Diabetes

Background The pathophysiologic mechanisms underlying painful symptoms in diabetic polyneuropathy (DPN) are poorly understood. They may be associated with MRI characteristics, which have not yet been investigated. Purpose To investigate correlations between nerve structure, load and spatial distribution of nerve lesions, and pain in patients with DPN. Materials and Methods In this prospective single-center cross-sectional study, participants with type 1 or 2 diabetes volunteered between June 2015 and March 2018. Participants underwent 3-T MR neurography of the sciatic nerve with a T2-weighed fat-suppressed sequence, which was preceded by clinical and electrophysiologic tests. For group comparisons, analysis of variance or the Kruskal-Wallis test was performed depending on Gaussian or non-Gaussian distribution of data. Spearman correlation coefficients were calculated for correlation analysis. Results A total of 131 participants (mean age, 62 years ± 11 [standard deviation]; 82 men) with either type 1 (n = 45) or type 2 (n = 86) diabetes were evaluated with painful (n = 64), painless (n = 37), or no (n = 30) DPN. Participants who had painful diabetic neuropathy had a higher percentage of nerve lesions in the full nerve volume (15.2% ± 1.6) than did participants with nonpainful DPN (10.4% ± 1.7, P = .03) or no DPN (8.3% ± 1.7; P < .001). The amount and extension of T2-weighted hyperintense nerve lesions correlated positively with the neuropathy disability score (r = 0.37; 95% confidence interval [CI]: 0.21, 0.52; r = 0.37; 95% CI: 0.20, 0.52, respectively) and the neuropathy symptom score (r = 0.41; 95% CI: 0.25, 0.55; r = 0.34; 95% CI: 0.17, 0.49, respectively). Negative correlations were found for the tibial nerve conduction velocity (r = -0.23; 95% CI: -0.44, -0.01; r = -0.37; 95% CI: -0.55, -0.15, respectively). The cross-sectional area of the nerve was positively correlated with the neuropathy disability score (r = 0.23; 95% CI: 0.03, 0.36). Negative correlations were found for the tibial nerve conduction velocity (r = -0.24; 95% CI: -0.45, -0.01). Conclusion The amount and extension of T2-weighted hyperintense fascicular nerve lesions were greater in patients with painful diabetic neuropathy than in those with painless diabetic neuropathy. These results suggest that proximal fascicular damage is associated with the evolution of painful sensory symptoms in diabetic polyneuropathy. © RSNA, 2019 Online supplemental material is available for this article.

Can ultrasound imaging be used for the diagnosis of carpal tunnel syndrome in diabetic patients? A systemic review and network meta-analysis

BACKGROUND

High-resolution ultrasound (US) becomes a reliable tool for diagnosing carpal tunnel syndrome (CTS), but whether it can be applied to patients with preexisting diabetes mellitus (DM) remains unclear.

METHODS

We searched PubMed and Embase and systemically reviewed studies exploring the median nerve CSAs at the wrist level by US imaging. Nine studies enrolling at least one subgroup comprising patients with both DM and CTS were included for network meta-analysis. The primary outcome was the inter-group difference of the wrist-level median nerve CSA.

RESULTS

The median nerve size at the wrist level was larger in patients with only CTS than in patients with only DM [CSA difference = 3.14 mm², 95% confidence interval (CI) 1.92-4.35]. Patients with DM and CTS had a slightly enlarged median nerve CSA than did patients with only CTS, but the difference was not statistically significant (0.52 mm², 95% CI - 0.54 to 1.59). According to rank probabilities, median nerve CSAs in patients with DM and CTS were likely to be ranked as the largest, followed by patients with only CTS, patients with only DM, and healthy controls. Furthermore, median nerve CSAs seemed smaller in patients with than without diabetic polyneuropathy.

CONCLUSIONS

Although DM causes swelling of the median nerve at the wrist level, patients with CTS have a larger CSA regardless of preexisting DM. The add-on effect of DM on median nerve CSAs in patients with CTS is limited. Diabetic polyneuropathy tends to result in less swollen median nerves in the CTS population.

High resolution ultrasonography of the tibial nerve in diabetic peripheral neuropathy

Aim of the study

High-resolution ultrasonography of the tibial nerve is a fast and non invasive tool for diagnosis of diabetic peripheral neuropathy. Our study was aimed at finding out the correlation of the cross sectional area and maximum thickness of nerve fascicles of the tibial nerve with the presence and severity of diabetic peripheral neuropathy.

Material and methods

75 patients with type 2 diabetes mellitus clinically diagnosed with diabetic peripheral neuropathy were analysed, and the severity of neuropathy was determined using the Toronto Clinical Neuropathy Score. 58 diabetic patients with no clinical suspicion of diabetic peripheral neuropathy and 75 healthy non-diabetic subjects were taken as controls. The cross sectional area and maximum thickness of nerve fascicles of the tibial nerves were calculated 3 cm cranial to the medial malleolus in both lower limbs.

Results

The mean cross sectional area (22.63 +/- 2.66 mm²) and maximum thickness of nerve fascicles (0.70 mm) of the tibial nerves in patients with diabetic peripheral neuropathy compared with both control groups was significantly larger, and statistically significant correlation was found with the Toronto Clinical Neuropathy Score (p < 0.001). The diabetic patients with no signs of peripheral neuropathy had a larger mean cross sectional area (14.40 +/- 1.72 mm²) and maximum thickness of nerve fascicles of the tibial nerve (0.40 mm) than healthy non-diabetic subjects (12.42 +/- 1.01 mm² and 0.30 mm respectively).

Conclusion

The cross sectional area and maximum thickness of nerve fascicles of the tibial nerve is larger in diabetic patients with or without peripheral neuropathy than in healthy control subjects, and ultrasonography can be used as a good screening tool in these patients.

Magnetic Resonance Neurography Visualizes Abnormalities in Sciatic and Tibial Nerves in Patients With Type 1 Diabetes and Neuropathy

This study evaluates whether diffusion tensor imaging magnetic resonance neurography (DTI-MRN), T2 relaxation time, and proton spin density can detect and grade neuropathic abnormalities in patients with type 1 diabetes. Patients with type 1 diabetes (n = 49) were included-11 with severe polyneuropathy (sDPN), 13 with mild polyneuropathy (mDPN), and 25 without polyneuropathy (nDPN)-along with 30 healthy control subjects (HCs). Clinical examinations, nerve conduction studies, and vibratory perception thresholds determined the presence and severity of DPN. DTI-MRN covered proximal (sciatic nerve) and distal (tibial nerve) nerve segments of the lower extremity. Fractional anisotropy (FA) and the apparent diffusion coefficient (ADC) were calculated, as were T2 relaxation time and proton spin density obtained from DTI-MRN. All magnetic resonance findings were related to the presence and severity of neuropathy. FA of the sciatic and tibial nerves was lowest in the sDPN group. Corresponding with this, proximal and distal ADCs were highest in patients with sDPN compared with patients with mDPN and nDPN, as well as the HCs. DTI-MRN correlated closely with the severity of neuropathy, demonstrating strong associations with sciatic and tibial nerve findings. Quantitative group differences in proton spin density were also significant, but less pronounced than those for DTI-MRN. In conclusion, DTI-MRN enables detection in peripheral nerves of abnormalities related to DPN, more so than proton spin density or T2 relaxation time. These abnormalities are likely to reflect pathology in sciatic and tibial nerve fibers.

Nerve ultrasound in electrophysiologically verified tarsal tunnel syndrome

INTRODUCTION

Tarsal tunnel syndrome (TTS) arises from tibial nerve damage under the flexor retinaculum of the fibro-osseus tunnel at the medial malleolus. It is notoriously difficult to diagnose, as many other foot pathologies result in a similar clinical picture. We examined the additional value of nerve ultrasound in patients with tarsal tunnel syndrome confirmed by nerve conduction.

METHODS

We performed a retrospective analysis of nerve ultrasound changes in electrophysiologically confirmed TTS spanning our records from 2007 to 2015.

RESULTS

Nine feet with TTS were identified, all of which showed abnormal nerve ultrasound findings, which in 6 feet, led to identification of the underlying cause.

CONCLUSIONS

This study shows that nerve ultrasound is abnormal in all cases of electrophysiologically verified TTS. The pattern of nerve abnormality is varied. This, and the fact that in the majority of patients causation was identified, suggests nerve ultrasound should form part of standard work-up for TTS. Muscle Nerve 53: 906-912, 2016.