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•Higher motor execution and planning cortical activity in TBPL (bionic hand) patients.•Interhemispheric reduced structural and increased functional connectivity in patients.•Increased corticothalamic functional connectivity in patients without a bionic hand.•Underlying increased central effort necessary for motor execution and planning.•Possible compensation for decreased interhemispheric and subcortical connectivity. Traumatic brachial plexus lesions (TBPL) can lead to permanent impairment of hand function despite timely brachial plexus surgical treatment. In selected cases with no recovery of hand function, the affected forearm can be amputated and replaced by a bionic hand to regain prehensile function. This cross-sectional study aimed to assess (sub)cortical motor activity and functional connectivity changes after TBPL and bionic reconstruction. Cortical activity was measured with functional MRI (fMRI) during execution, and imagery of hand closing movements with the affected and healthy arm and single subject analysis was performed on the fMRI data. An electromyography training session was performed before fMRI to ensure correct task performance. Additionally, functional connectivity, diffusion tensor imaging (DTI), and cortical thickness were analyzed. Six healthy controls (4 men, median age 27, range 22–54), three TBPL patients without prosthetic reconstruction (3 men, median age 50, range 19–58), and two TBPL patients with a prosthetic reconstruction (2 men, median age 41, range 40–41) were included. In patients, cortical activity in the premotor gyrus and supplementary motor cortex (SMC) was higher and more widespread during both actual and imagery movements of the affected as well as the unaffected arm. Moreover, patients showed increased interhemispheric functional connectivity from the most active voxel in the precentral gyrus and SMC in the actual movement task. Subcortical activation of the thalamus and pallidum was observed only in non-prosthesis patients during actual movements. Corticothalamic functional connectivity was increased mainly in patients without prosthesis during actual and imagery movements. There were no differences in cortical thickness between participants. TBPL patients showed fewer structural DTI-based interhemispheric connections between the left and right precentral gyrus and superior frontal gyrus than controls. Patients without prosthesis also exhibited fewer structural connections between the left and right thalamus and pallidum, whereas those with prosthesis demonstrated increased structural connectivity compared to controls. The increased and more widespread cortical activity and functional connectivity after TBPL may be due to increased central effort necessary for motor execution and planning, representing a compensation mechanism for the decrease of interhemispheric and subcortical connectivity. The initial loss of white matter may be counteracted by increased function and grey matter recruitment, which seems necessary even after white matter recovery later with prosthesis use. The clinical implication of our findings is that a selected group of TBPL patients may benefit from an earlier timing of bionic restoration of hand function.

Contrast-enhanced magnetic resonance neurography (CE-MRN) holds promise for diagnosing brachial plexopathy by enhancing nerve visualization and revealing additional imaging features in various lesions. This study aims to validate CE-MRN’s efficacy in improving brachial plexus (BP) imaging across different patient cohorts. Seventy-one subjects, including 19 volunteers and 52 patients with BP compression/entrapment, injury, and neoplasms, underwent both CE-MRN and plain MRN. Two radiologists assessed nerve visibility, with inter-reader agreement evaluated. Quantitative parameters such as signal intensity (SI), contrast-to-noise ratio (CNR), and contrast ratio (CR) of the C7 nerve were measured. Both qualitative scoring and quantitative metrics were compared between CE-MRN and plain MRN within each patient group. Patient classification followed the Neuropathy Score Reporting and Data System (NS-RADS), summarizing additional imaging features for each brachial plexopathy type. Inter-reader agreement for qualitative assessment was strong. CE-MRN significantly enhanced BP visualization and nerve-tissue contrast across all cohorts, particularly in volunteers and patients with injuries. It also uncovered additional imaging features such as hypointense signals in ganglia, compressed nerve sites, and neoplastic enhancements. CE-MRN effectively mitigated muscle edema and vascular contamination, enabling precise classification of BP injuries. Overall, CE-MRN consistently enhances BP visualization and provides valuable imaging features for accurate diagnosis.

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/mm 2 ) 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%).

BackgroundPerineural spread (PNS) is an emerging mechanism for progressive, non-traumatic brachial plexopathy. We aim to summarize the pathologies (tumor and infection) shown to have spread along or to the brachial plexus, and identify the proposed mechanisms of perineural spread.MethodsA focused review of the literature was performed pertaining to pathologies with identified perineural spread to the brachial plexus.ResultsWe summarized pathologies currently reported to have PNS in the brachial plexus and offer a structure for understanding and describing these pathologies with respect to their interaction with the peripheral nervous system.ConclusionsPerineural spread is an underrepresented entity in the literature, especially regarding the brachial plexus. It can occur via a primary or secondary mechanism based on the anatomy, and understanding this mechanism helps to support biopsies of sacrificial nerve contributions, leading to more effective and timely treatment plans for patients.

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.

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.

Abstract BACKGROUND Traumatic brachial plexus injury (BPI) can result in debilitating sequelae of the upper extremity. Presently, therapeutic decisions are based on the mechanism of injury, serial physical examination, electromyography, nerve conduction, and imaging studies. While magnetic resonance imaging is the current imaging modality of choice for BPI, ultrasound is a promising newcomer that is inexpensive, accessible, and available at point of care. OBJECTIVE To evaluate ultrasound as a diagnostic tool in the assessment of traumatic adult BPI through a systematic review. METHODS An electronic literature search was completed in MEDLINE, EMBASE, CINAHL, and Cochrane databases up to July 2016. Two independent reviewers completed the screening and data extraction. Methodological quality of studies was evaluated using the Quality Assessment of Diagnostic Accuracy Studies-2 tool. Statistical analysis was used to estimate pooled sensitivities and study heterogeneity. RESULTS Seven studies were included. Four studies compared the detection of pre- and postganglionic lesions at different levels (C5-T1) to surgical exploration as the reference standard. Sensitivity of lesion detection was greater in the upper and middle spinal nerves: C5 (93%, confidence interval [CI] = 78%-100%), C6 (94%, CI = 82%-100%), and C7 (95%, CI = 86%-100%) than in the lower: C8 (71%, CI = 36%-95%) and T1 (56%, CI = 29%-81%). CONCLUSION Individual studies demonstrate ultrasound as an effective diagnostic tool for traumatic adult BPI. Sensitivity of lesion detection was noted to be greater in the upper and middle (C5-C7) than in the lower spinal nerves (C8, T1). Further standardized studies should be performed to confirm the utility of ultrasound in the diagnosis of traumatic adult BPI.

Background: Neurolymphomatosis is a process of neoplastic endoneurial invasion, most strongly associated with non-Hodgkin’s lymphoma. It must be distinguished from paraneoplastic, metabolic, nutritional and treatment-related causes of neuropathy that are common in this patient population. Methods: This brief case series illustrates the protean manifestations of neurolymphomatosis of the brachial plexus, ranging from focal distal mononeuropathy to multifocal brachial plexopathy, either as the index manifestation of lymphoma or as a complication of relapsing disease. Results: Prominent asymmetry, pain and nodular involvement on neuroimaging may help distinguish neurolymphomatosis from paraneoplastic immune demyelinating radiculoneuropathy. MR neurography criteria for the diagnosis of neurolymphomatosis include hyperintensity on T2 and STIR sequences, focal and diffuse nerve enlargement with fascicular disorganization and gadolinium enhancement. No specific anatomical distribution within the brachial plexus has, however, been found to be characteristic. Fluorodeoxyglucose-positron emission tomography (FDG-PET) imaging is the imaging modality with the highest sensitivity for detection of nodal or extranodal spread in lymphoma. Conclusions: Brachial plexus neuropathy in neurolymphomatosis is highly protean in its distribution, semiology and relation to lymphoma staging. Dedicated MRI and PET-CT imaging are leading diagnostic modalities. Neurolymphomatose du plexus brachial et de ses branches : étude de série de cas et recension des écrits. Contexte: La neurolymphomatose constitue un processus d’invasion endoneurale néoplasique le plus souvent associé à des lymphomes non hodgkiniens. Il doit ainsi être distingué de l’ensemble des causes de la neuropathie : paranéoplasiques, métaboliques, nutritionnelles ainsi que celles liées à l’administration d’un traitement. À noter que ces causes sont répandues au sein du groupe de patients à l’étude. Méthodes: Cette étude succincte d’une série de cas entend se pencher sur les manifestations protéiformes de la neurolymphomatose du plexus brachial, lesquelles, que ce soit comme indices de la présence de lymphomes ou résultant des complications d’une maladie récurrente, vont de la mono-neuropathie focale distale à la plexopathie brachiale multifocale. Résultats: Il est possible qu’une asymétrie importante, de la douleur et la présence de nodules détectés par neuro-imagerie contribuent à établir une distinction entre la neurolymphomatose et la radiculoneuropathie démyélinisante paranéoplasique d’origine immunitaire. Les critères diagnostiques de la neurolymphomatose au moyen de la neurographie par résonance magnétique (NRM) incluent notamment l'hyper-intensité en séquences STIR (pondération en T2) ainsi que l’augmentation focale et diffuse du volume des nerfs associée à une désorganisation fasciculaire et à l’utilisation du gadolinium afin d’améliorer le contraste des images. Cela dit, précisons qu’aucune distribution anatomique spécifique à l’intérieur du plexus brachial n’est apparue caractéristique. La tomographie par émission de positrons (18FDG) est la modalité d’imagerie dont la sensibilité de contraste, la plus élevée, permet de détecter une propagation nodulaire ou extra-nodulaire dans le cas de lymphomes. Conclusions: Dans le cas de la neurolymphomatose, on a observé que la neuropathie du plexus brachial était grandement protéiforme tant en ce qui concerne sa distribution, sa sémiologie qu’en relation avec la stadification des lymphomes. Tant des examens spécifiques d’IRM que la tomographie par émission de positrons demeurent des techniques diagnostiques de premier plan.

Abstract 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.

Magnetic resonance neurography (MRN) is recognized as the imaging modality of choice in the evaluation of patients with brachial plexopathy. It adds vital information to the results of the clinical evaluation and electrodiagnostic tests and facilitates patient management. Its indications include both trauma and non-traumatic forms of plexopathy such as inflammatory, neoplastic and compressive. This article will familiarize readers with the routine MRN protocol in clinical practice and discuss the utility of the different sequences. The timing of the scan is important, especially with reference to trauma and this has been discussed. Both the advantages and limitations of MRN have been elaborated upon.