Evaluation of Infantile Brachial Plexopathy Using 3T MRI and High-Resolution Ultrasound: Experience From a Tertiary Care Centre.

BACKGROUND: Currently, clinical assessment is the main tool for the evaluation of brachial plexus injury, complemented by electrophysiologic studies (EPS), and imaging studies whenever available. Imaging plays an important role as it enables the differentiation of pre-ganglionic and postganglionic injuries, and adds objectivity to presurgical evaluation. OBJECTIVES: The primary objective was to evaluate the utility of magnetic resonance imaging (MRI) and high-resolution ultrasonography (USG) in the localization and characterization of brachial plexus injury in infants. MATERIALS AND METHODS: In this prospective study, 34 infants with signs and symptoms of brachial plexus injury were evaluated by clinical examination, EPS, MRI, and USG. Imaging findings were correlated with intraoperative findings in infants who underwent surgical management. The association between EPS and MRI findings, and USG and MRI findings were assessed using Fisher's exact test. Semi-quantitative subjective analysis of various MRI sequences was done as well. RESULTS: The most common findings of preganglionic injury and postganglionic injury, in our study, were pseudomeningocele and nerve thickening, respectively. MRI detection of injuries had a significant association with EPS findings. All MRI-detected injuries had a muscle power of grade 3 or less. muscle. Three-dimensional (3D) short tau inversion recovery (STIR) sequence was found to be superior for detecting postganglionic injuries (P < 0.05). CONCLUSION: Imaging studies enable localization of the site of injury, determining the extent, and nature/morphology of injury. The gamut of findings obtained from MRI is far wider compared to that from USG. USG can be used as the first-line screening investigation.

3D SHINKEI MR neurography in evaluation of traumatic brachial plexus.

3D SHINKEI neurography is a new sequence for imaging the peripheral nerves. The study aims at assessing traumatic brachial plexus injury using this sequence. Fifty-eight patients with suspected trauma induced brachial plexus injury underwent MR neurography (MRN) imaging in 3D SHINKEI sequence at 3 T. Surgery and intraoperative somatosensory evoked potentials or clinical follow-up results were used as the reference standard. MRN, surgery and electromyography (EMG) findings were recorded at four levels of the brachial plexus-roots, trunks, cords and branches. Fifty-eight patients had pre- or postganglionic injury. The C5-C6 nerve postganglionic segment was the most common (average 42%) among the postganglionic injuries detected by 3D SHINKEI MRN. The diagnostic accuracy (83.75%) and the specificity (90.30%) of MRN higher than that of EMG (p < 0.001). There was no significant difference in the diagnostic sensitivity of MRN compared with EMG (p > 0.05). Eighteen patients with brachial plexus injury underwent surgical exploration after MRN examination and the correlation between MRN and surgery was 66.7%. Due to the high diagnostic accuracy and specificity, 3D SHINKEI MRN can comprehensively display the traumatic brachial plexus injury. This sequence has great potential in the accurate diagnosis of traumatic brachial plexus injury.

Abnormal Brachial Plexus Differentiation from Routine Magnetic Resonance Imaging: An AI-based Approach.

Automatic abnormality identification of brachial plexus (BP) from normal magnetic resonance imaging to localize and identify a neurologic injury in clinical practice (MRI) is still a novel topic in brachial plexopathy. This study developed and evaluated an approach to differentiate abnormal BP with artificial intelligence (AI) over three commonly used MRI sequences, i.e. T1, FLUID sensitive and post-gadolinium sequences. A BP dataset was collected by radiological experts and a semi-supervised artificial intelligence method was used to segment the BP (based on nnU-net). Hereafter, a radiomics method was utilized to extract 107 shape and texture features from these ROIs. From various machine learning methods, we selected six widely recognized classifiers for training our Brachial plexus (BP) models and assessing their efficacy. To optimize these models, we introduced a dynamic feature selection approach aimed at discarding redundant and less informative features. Our experimental findings demonstrated that, in the context of identifying abnormal BP cases, shape features displayed heightened sensitivity compared to texture features. Notably, both the Logistic classifier and Bagging classifier outperformed other methods in our study. These evaluations illuminated the exceptional performance of our model trained on FLUID-sensitive sequences, which notably exceeded the results of both T1 and post-gadolinium sequences. Crucially, our analysis highlighted that both its classification accuracies and AUC score (area under the curve of receiver operating characteristics) over FLUID-sensitive sequence exceeded 90%. This outcome served as a robust experimental validation, affirming the substantial potential and strong feasibility of integrating AI into clinical practice.

Diagnosis of obstetric brachial plexus injury in a 2-year-old girl using high­frequency ultrasonography.

We describe an unusual case of infant obstetric brachial plexus injury located in the cervical (C)5-C6 brachial plexus nerve, which was preoperatively diagnosed using high-frequency ultrasonography (US) at 2 years of age. The girl was diagnosed with a right clavicular fracture because of shoulder dystocia. She had been showing movement limitations of her entire right upper limb after fracture healing and was then referred to our hospital at 2 years of age. High-frequency US showed that the roots of the right brachial plexus ran continuously, but the diameter of C6 was thinner on the affected side than on the contralateral side (right 0.12 cm vs. left 0.20 cm). A traumatic neuroma had formed at the upper trunk, which was thicker (diameter: right 0.35 cm vs. left 0.23 cm; cross-sectional area: right 0.65 cm2 vs. left 0.31 cm2) at the level of the supraclavicular fossa. Intraoperative findings were consistent with ultrasound findings. Postoperative pathology confirmed brachial plexus traumatic neuroma.

Diagnostic Performance of 3D-NERVE as an Adjunct to Electromyography for the Assessment of Brachial Plexus Injury in Infants.

Objective: This study aimed to explore diagnostic performance of 3D-NERVE as an adjunct to electromyography for the assessment of brachial plexus injury in infants. Methods: Imaging of infants with brachial plexus injury using 3D-NERVE and/or 3D-STIR from 2019 to 2022 were reviewed. Images were evaluated between the 2 sequences for nerve-to-fat ratio, nerve-to-muscle ratio, muscle-to-fat ratio, fat suppression homogeneity, and display rate of brachial plexus branches. Results: This study included 37 infants who were referred for a clinical diagnosis of brachial plexus injury. A total of 21 infants accepted 3D-NERVE sequence scanning, and 16 infants accepted 3D-NERVE and 3D-STIR sequences scanning. The results of examination were generally consistent with electromyography. The 2 sequences were compared, yielding the following results. There were no pulsation artifacts (0/16), and 1 case with heterogeneous fat saturation (1/16) was seen on 3D-NERVE. There were no pulsation artifacts (0/16), and 5 cases with heterogeneous fat saturation (5/16) were seen on 3D-STIR. 3D-NERVE performed better (P < .05) for nerve-to-fat and nerve-to-muscle ratios compared with 3D-STIR, and no significant difference in the muscle-to-fat ratio (P > .05). The 3D-NERVE and STIR helped depict 100% (16/16) of the brachial roots and brachial plexus trunk. Brachial plexus bundles and brachial plexus branches were observed in 93.75% (15/16) and 68.75% (11/16) of the 3D-NERVE and 93.75% (15/16) and 62.5% (10/16) of the 3D-STIR, respectively. The differences were not statistically significant (P > .05). Conclusion: Nerve trauma was better visualized with the 3D-NERVE, which is an effective adjunct to electromyography for doctors to assess brachial plexus injury and consequently helps in better treatment planning.

The diagnostic utility of inspiratory-expiratory radiography for the assessment of phrenic nerve palsy associated with brachial plexus injury.

BACKGROUND: The phrenic nerve is commonly injured with trauma to the brachial plexus. Hemi-diaphragmatic paralysis may be well-compensated in healthy individuals at rest but can be associated with persistent exercise intolerance in some patients. This study aims to determine the diagnostic value of inspiratory-expiratory chest radiography compared to intraoperative stimulation of the phrenic nerve for assessing phrenic nerve injury associated with brachial plexus injury. METHODS: Over a 21-year period, the diagnostic utility of three-view inspiratory-expiratory chest radiography for identification of phrenic nerve injury was determined by comparison to intraoperative phrenic nerve stimulation. Multivariate regression analysis was used to identify independent predictors of phrenic nerve injury and having an incorrect radiographic diagnosis. RESULTS: A total of 237 patients with inspiratory-expiratory chest radiography underwent intraoperative testing of phrenic nerve function. Phrenic nerve injury was present in approximately one-fourth of cases. Preoperative chest radiography had a sensitivity of 56%, specificity of 93%, positive predictive negative of 75%, and negative predictive value of 86% for identification of a phrenic nerve palsy. Only C5 avulsion was found to be a predictor of having an incorrect diagnosis of phrenic nerve injury on radiography. CONCLUSION: While inspiratory-expiratory chest radiography has good specificity for detecting phrenic nerve injuries, a high number of false negatives suggest that it should not be relied upon for routine screening of dysfunction after traumatic brachial plexus injury. This is likely multifactorial and relates to variation in diaphragm shape and position, as well as limitations regarding static image interpretation of a dynamic process.

A pentavalent approach for the evaluation of traumatic brachial plexopathy on MRI: correlation of macropattern and micropattern.

Macropattern analysis of traumatic brachial plexopathy (TBP) by Magnetic Resonance Imaging (MRI) encompasses localization of injured segments and determination of the severity of injury. The micropattern analysis implies the correlation of the MRI features of TBP with Sunderland's grading of the nerve injury, thereby guiding the management protocol. This review article presents a simplified novel pentavalent approach for the radiological anatomy of brachial plexus, MRI acquisition protocol for the evaluation of brachial plexus, cardinal imaging signs of TBP, and their correlation with Sunderland's microanatomical grading.

Clinical Diagnosis of the Infantile Shoulder Subluxation in Residual Brachial Plexus Birth Injury and Its Correlation With Ultrasound Diagnosis.

INTRODUCTION AND AIMS OF STUDY: Timely detection of shoulder subluxation in infants with brachial plexus birth injury (BPBI) is essential to prevent the progression of glenohumeral deformity. Shoulder ultrasonography (USG) is routinely used to detect an infantile subluxation/dislocation, but its use is limited because of the paucity of expert radiologists in developing countries. The aim of this study was to determine the clinical examination predictors to determine shoulder subluxation in patients with BPBI correlating with ultrasound confirmation. METHODS: We prospectively studied children who presented to our hospital between 2017 and 2021 diagnosed as brachial plexus birth injury. In patients developing internal rotation contracture of the shoulder, we looked for 3 standard clinical signs: reduced passive external rotation <60 degrees, deep anterior crease (DAC) and relatively short arm segment. Shoulder subluxation was defined as USG measurement of alpha angle>30 degrees and ossific nuclei of the humerus lying behind the dorsal scapular line. Sensitivity and specificity were used to assess their efficacy in clinical diagnosis of shoulder subluxation in different groups. The predicted probability of shoulder subluxation from each prediction rule was compared with actual distributions based on USG confirmation. RESULTS: Of the 58 BPBI infants who developed PER<60 degrees at the shoulder, 41 had USG confirmed shoulder subluxation. The 2 independent predictors of shoulder subluxation (PER<45 degrees and DAC) were identified in the current patient population based on data analysis. The presence of short arm segment is a very specific marker of shoulder subluxation but not sensitive. The predicted probability of shoulder subluxation from the prediction rule combining all the 3 markers were similar to the actual distributions in the current patient population. CONCLUSIONS: PER<45 degrees and presence of deep anterior crease are clinical markers indicating shoulder dislocation in patients with BPBI developing reduced external rotation at the shoulder. On the basis of the proposed clinical diagnosis algorithm, the above markers along with the selective use of USG can help in early detection and treatment of infantile shoulder dislocation.

Application of CUBE-STIR MRI and high-frequency ultrasound in contralateral cervical 7 nerve transfer surgery.

OBJECTIVE: The objective of the study was to investigate the feasibility of CUBE-SITR MRI and high-frequency ultrasound for the structural imaging of the brachial plexus to exclude neoplastic brachial plexopathy or structural variation and measure the lengths of anterior and posterior divisions of the C7 nerve, providing guidelines for surgeons before contralateral cervical 7 nerve transfer. METHODS: A total of 30 patients with CNS and 20 with brachial plexus injury were enrolled in this retrospective study. All patients underwent brachial plexus CUBE-STIR MRI and high-frequency ultrasound, and the lengths of the anterior and posterior divisions of C7 nerve were measured before surgery. Precise length of anterior and posterior divisions of contralateral C7 nerve was measured during surgery. RESULTS: MRI-measured lengths of anterior and posterior divisions of C7 nerves were positively correlated with that measured during surgery (anterior division, r = 0.94, p < .01; posterior division, r = 0.92, p < .01). High agreement was found between MRI-measured and intra-surgery measured length of anterior and posterior divisions of C7 nerve by BLAD-ALTMAN analysis. Ultrasonography could feasibly image supraclavicular C7 nerve and recognize small variant branches derived from middle trunk of C7 nerve root, which could be dissected intra-operatively and confirmed by electromyography during the procedure of contralateral C7 nerve transfer. CONCLUSION: CUBE-STIR MRI had advantages for the imaging of the brachial plexus and measurement of the length of root-trunk-anterior/posterior divisions of C7 nerve. The clinical role of ultrasonography may be a simple way of evaluating general condition of C7 nerve and provide guidelines for contralateral C7 nerve transfer surgery.

Nerve Imaging in the Wrist.

Neuropathic symptoms involving the wrist are a common clinical presentation that can be due to a variety of causes. Imaging plays a key role in differentiating distal nerve lesions in the wrist from more proximal nerve abnormalities such as a cervical radiculopathy or brachial plexopathy. Imaging complements electrodiagnostic testing by helping define the specific lesion site and by providing anatomical information to guide surgical planning. This article reviews nerve anatomy, normal and abnormal findings on ultrasonography and magnetic resonance imaging, and common and uncommon causes of neuropathy.

Brachial Plexus Birth Palsy: Practical Concepts for Radiologists.

Brachial plexus birth palsy (BPBP) is classified as a preganglionic or postganglionic injury based on the site of injury. Most patients recover spontaneously and are followed up with clinical evaluation; however, permanent sequelae are not uncommon. For patients with persistent neurologic deficits, clinical and radiologic evaluation is crucial. Untreated BPBP can progress to significant sequelae, such as muscle contractures and glenohumeral dysplasia (GHD). Timely characterization of these entities based on different imaging modalities is a high priority for optimal patient outcomes. We describe the anatomy and pathogenesis, as well as the different imaging modalities involved in the evaluation and classification of BPBP and GHD.

Clinical, electrophysiological, and imaging findings in childhood brachial plexus injury.

AIM: To assess the prognostic capabilities of various diagnostic modalities for childhood brachial plexus injuries (BPIs) and brachial plexus birth injury (BPBI) and postneonatal BPI. METHOD: In this single-center retrospective cross-sectional study, we examined children with BPIs diagnosed or confirmed by electrodiagnostic studies between 2013 and 2020, and compared the prognostic value of various components of the electrophysiologic findings, magnetic resonance imaging (MRI) data, and the Active Movement Scale (AMS). We developed scoring systems for electrodiagnostic studies and MRI findings, including various components of nerve conduction studies and electromyography (EMG) for electrodiagnostic studies. RESULTS: We identified 21 children (10 females and 11 males) aged 8 days to 21 years (mean 8y 6.95mo) who had a total of 30 electrodiagnostic studies, 14 brachial plexus MRI studies, and 10 surgical procedures. Among the diagnostic modalities assessed, brachial plexus MRI scores, EMG denervation scores, and mean total EMG scores were the most valuable in predicting surgical versus non-surgical outcomes. Correspondingly, a combined MRI/mean total EMG score provided prognostic value. INTERPRETATION: Brachial plexus MRI scores and specific electrodiagnostic scores provide the most accurate prognostic information for children with BPI. Our grading scales can assist a multidisciplinary team in quantifying results of these studies and determining prognosis in this setting. WHAT THIS PAPER ADDS: A new scoring system to quantify results of electrodiagnostic and magnetic resonance imaging (MRI) studies is presented. Severity of denervation has good prognostic value for childhood brachial plexus injuries (BPIs). Composite electromyography scores have good prognostic value for childhood BPIs. Brachial plexus MRI has good prognostic value for childhood BPIs.

Diagnostic Ability of Ultrasonography in Brachial Plexus Root Injury at Different Stages Post-trauma.

Brachial plexus (BP) root injury often results in disability of the upper extremities. Improvements in high-frequency ultrasonography have enabled the visualization of BP nerve roots. This study was aimed at quantifying the diagnostic accuracy of ultrasonography in BP root injury at different stages post-trauma. A consecutive series of 170 patients with BP root injury between 2015 and 2019 were studied retrospectively and divided into three groups on the basis of time between injury and ultrasound examination (≤1 mo, 1-3 mo, >3 mo). Diagnosis of complete BP root injury under ultrasound was determined using a pre-defined criterion, including pseudomeningocele, retraction and rupture. Diagnostic accuracy was calculated based on surgical findings and intra-operative electrophysiological tests. Rates of detection of the cervical (C5-C8) and thoracic (T1) nerve roots under ultrasound were 99.4%, 99.4%, 99.4%, 95.9% and 79.4%, respectively. The sensitivity for complete BP root injury was 0.74, and the specificity was 0.91. No significant differences in sensitivity or specificity were observed across time stages. Ultrasound exhibited substantial consistency with surgical findings (κ = 0.70) for complete BP root injury at any stage post-injury. Ultrasound can be an optional method of diagnosis of complete BP root injury at an early stage post-injury.

Development of magnetic resonance imaging of brachial plexus neuralgia.

As the incidence of peripheral neurological diseases increases, the precise display of nerves becomes important in imaging examinations. Among them, the pain caused by brachial plexus neuropathy is very prominent, and the magnetic resonance imaging of nerve is quite complex and messy. This paper will systematically elaborate from the aspects of brachial plexus neuropathy, morphological and functional imaging, and post-processing.

Preoperative imaging assessment of the paralytic upper limb.

Imaging has become an essential tool in the study of the posttraumatic paralytic upper limb, in addition to the clinical examination and electroneuromyography. Upper extremity surgeons must be aware of how these different techniques contribute to the initial and preoperative assessment of nervous injuries. We review the appearance of traumatic nerve damage and muscle denervation during the initial injury assessment, focusing on the main aspects of brachial plexus injuries, paralysis after shoulder dislocation and traumatic damage to the radial nerve. Finally, we discuss the role of imaging for preoperative assessment of musculotendinous and osteoarticular palliative surgeries.

Diagnostic performance of diffusion-weighted MR neurography as an adjunct to conventional MRI for the assessment of brachial plexus pathology.

OBJECTIVE: To investigate the diagnostic performance of diffusion-weighted (DW) MR neurography as an adjunct to conventional MRI for the assessment of brachial plexus pathology. METHODS: DW MR neurography scans (short tau inversion recovery fat suppression and b-value of 800 s/mm2) of 15 consecutive patients with and 45 randomly selected patients without brachial plexus abnormalities were independently and blindly reviewed by a 5th year radiology resident, a junior neuroradiologist, and a senior neuroradiologist. RESULTS: Median interpretation times ranged between 20 and 30 s. Interobserver agreement was substantial (κ coefficients of 0.715-0.739). For the 5th year radiology resident, sensitivity was 53.3% (95% CI, 30.1-75.2%) and specificity was 100% (95% CI, 92.1-100%). For the junior neuroradiologist, sensitivity was 66.7% (95% CI, 41.7-84.8%) and specificity was 100% (95% CI, 92.1-100%). For the senior neuroradiologist, sensitivity was 73.3% (95% CI, 48.1-89.1%) and specificity was 95.6% (95% CI, 85.2-98.8%). Traumatic injury, metastases, radiation-induced plexopathy, schwannoma, and inflammatory process of unknown cause could be detected by the majority of readers (100% detection rate for each disease entity by at least two readers). Neuralgic amyotrophy, iatrogenic injury after first rib resection, and cervical disc herniation causing root compression were not detected by the majority of readers (0% detection rate for each disease entity by at least two readers). CONCLUSION: DW MR neurography may be a useful adjunct when assessing for brachial plexus abnormalities, because interpretation time is relatively short and the majority of abnormalities can be detected. KEY POINTS: • DW MR neurography interpretation time of the brachial plexus is relatively short (median interpretation times of 20 to 30 s). • Interobserver agreement between three readers with different levels of experience is substantial (κ coefficients of 0.715 to 0.739). • DW MR neurography can detect brachial plexus abnormalities with moderate sensitivity (53.3 to 73.3%) and high specificity (95.6 to 100%).

Predicting Healthy C5 Spinal Nerve Stumps Eligible for Grafting with MRI, Tinel Test, and Rhomboid Electromyography: A Retrospective Study of 295 Consecutive Brachial Plexus Surgeries.

Background MRI, Tinel test, and rhomboid electromyography (EMG) can be used to predict whether C5 spinal nerve stumps are healthy and eligible for grafting in acute adult brachial plexus injuries, but their comparative diagnostic efficacies have not been evaluated. Purpose To compare diagnostic performances of MRI, Tinel test, and rhomboid EMG in predicting healthy C5 spinal nerve stumps that are eligible for grafting. Materials and Methods This retrospective study included consecutive adult patients with acute brachial plexus injury who underwent microreconstructions between January 2008 and December 2018. Healthy C5 spinal nerve stumps eligible for grafting with preceding normal intradural nerve rootlets were diagnosed by an experienced neuroradiologist using an avulsion severity score system based on fast imaging employing steady-state acquisition or FIESTA neurography, which separates intradural nerve rootlets into normal, partial mild, severe, and complete avulsions. Tinel test and rhomboid EMG results were assessed by an experienced nerve surgeon and neurologist, respectively. The accuracy, sensitivity, and specificity of the three tests were compared using microdissection as the reference standard. P < .05 was considered to indicate a significant difference. Results A total of 251 patients (mean age, 31 years ± 13 [standard deviation]; 217 men) with brachial plexus injuries who had -undergone MRI (n = 251), Tinel test (n = 235), rhomboid EMG (n = 181) and MRI, Tinel test, and EMG (n = 172) were -included. Accuracy, sensitivity, and specificity, respectively, in predicting healthy C5 spinal nerve stumps eligible for grafting were 93% (233 of 251), 84% (58 of 69), and 96% (175 of 182) for MRI; 59% (139 of 235), 56% (37 of 66), and 60% (102 of 169) for Tinel test; and 39% (71 of 181), 85% (43 of 50), and 21% (28 of 131) for rhomboid EMG. MRI (area under the receiver operating characteristic curve [AUC], 0.90; P < .001) -outperformed MRI and Tinel test (AUC, 0.74), Tinel test (AUC, 0.59), and rhomboid EMG (AUC, 0.53). Conclusion MRI performed best in the prediction of healthy graftable C5 spinal nerve stumps in acute adult brachial plexus injuries. © RSNA, 2021 Online supplemental material is available for this article.