Pictorial essay: Role of magnetic resonance imaging in evaluation of brachial plexus pathologies

Magnetic resonance imaging for diagnosis of suspected neurogenic thoracic outlet syndrome-a systematic scoping review

Background: Neurogenic Thoracic Outlet Syndrome (nTOS) is a rare pathology caused by dynamic conditions or compression of neurovascular structures in the thoracic outlet region. nTOS can be difficult to diagnose due to nonspecific symptoms and magnetic resonance imaging (MRI) techniques are increasingly used to aid the diagnosis and surgical planning. This scoping systematic review explores how MRI is used for diagnosing nTOS and summarizes details of published MRI protocols. Methods: A systematic screening of PubMed, Cochrane, Web of Science, and CINAHL databases using PRISMA-IPD guidelines was conducted in September 2022 to include full-text English papers on MRI and nTOS. Inclusion criteria involved studies describing MRI protocols for the diagnosis of TOS, with a focus on the imaging sequences and protocols. Results: 6289 papers were screened to include 28 papers containing details of MRI protocols. The details of MRI protocols in the analyzed articles were incomplete in all studies. Most authors used 1.5T systems and included T1 and T2-weighted sequences. Most studies applied fat suppression, mainly with STIR. Positioning of the arm differed between studies, including neutral, hyperabducted and abducted and externally rotated positions. Conclusion: Our review highlights a prevalent lack of detailed MRI protocol documentation for brachial plexus. Authors primarily rely on conventional 1.5T systems, employing standard T1 and T2-weighted sequences. The adoption of novel MRI sequences is notably lacking, and fat suppression techniques predominantly adhere to older methods as STIR. There is a clear imperative for authors to provide more comprehensive reporting of the MRI protocols utilized in their studies, ultimately enhancing comparability and clinical applicability. Establishing clear protocol reporting guidelines is crucial to allow for comparison between studies.

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.

Magnetic resonance imaging of the brachial plexus. Part 1: Anatomical considerations, magnetic resonance techniques, and non-traumatic lesions

For magnetic resonance imaging (MRI) of non-traumatic brachial plexus (BP) lesions, sequences with contrast injection should be considered in the differentiation between tumors, infection, postoperative conditions, and post-radiation changes. The most common non-traumatic inflammatory BP neuropathy is radiation neuropathy. T2-weighted images may help to distinguish neoplastic infiltration showing a high signal from radiation-induced neuropathy with fibrosis presenting a low signal.

MRI findings in inflammatory BP neuropathy are usually absent or discrete. Diffuse edema of the BP localized mainly in the supraclavicular part of BP, with side-to-side differences, and shoulder muscle denervation may be found on MRI.

BP infection is caused by direct infiltration from septic arthritis of the shoulder joint, spondylodiscitis, or lung empyema.

MRI may help to narrow down the list of differential diagnoses of tumors. The most common tumor of BP is metastasis. The most common primary tumor of BP is neurofibroma, which is visible as fusiform thickening of a nerve. In its solitary state, it may be challenging to differentiate from a schwannoma.

The most common MRI finding is a neurogenic variant of thoracic outlet syndrome with an asymmetry of signal and thickness of the BP with edema. In abduction, a loss of fat directly related to the BP may be seen.

Diffusion tensor imaging is a promising novel MRI sequences; however, the small diameter of the nerves contributing to the BP and susceptibility to artifacts may be challenging in obtaining sufficiently high-quality images.

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MRI allows narrowing the list of differential diagnoses of brachial plexus lesions.

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MRI helps to distinguish neoplastic infiltration from radiation neuropathy in T2-weighted images.

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Differentiation between tumors, infection, postoperative conditions and post-radiation changes is possible with contrast.

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MRI helps to determine the extent of the infection.

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Diffusion tensor MRI is a promising method for brachial plexus assessment.

Amyotrophic Monoplegia Secondary to Posttraumatic Rupture of the Brachial Plexus's Roots: A Case Report and Review of the Literature

Brachial plexus lesions most often occur in multiple trauma. We report a case of a 37-year-old patient who presented an upper left limb total sensitivomotor deficit and amyotrophy after a cervical and upper limb trauma. Cervical magnetic resonance imaging (MRI) was performed. It noted pseudomeningoceles at the levels of C6-C7, C7-D1, and D1-D2 in T1 hyposignal , T2 and STIR hypersignal , not enhanced by the injection of Gadolinium extending in foraminal and extraforaminal spaces without visualization of the corresponding rootlets. Traumatic brachial plexus injury is a potentially serious debilitating injury which can be well explored on MRI.

Clinical, electrodiagnostic and imaging features of true neurogenic thoracic outlet syndrome: Experience at a tertiary referral center

OBJECTIVE

True neurogenic thoracic outlet syndrome (TN-TOS) is an extremely rare neuromuscular disease. We report clinical, electrodiagnostic and radiologic features of patients with TN-TOS.

METHODS

Retrospective chart review of patients satisfying criteria was done. Nerve conduction study (NCS) and needle electromyography (EMG) of upper extremity were reviewed. Brachial plexus MRI and computed tomography angiography (CTA) were also reviewed.

RESULTS

Thirteen TN-TOS patients were identified. The most common neurologic signs were hypesthesia in the medial forearm or ulnar digits and weakness of the abductor pollicis brevis (APB) muscle. In NCS, medial antebrachial cutaneous (MABC) sensory nerve action potential amplitude was decreased in all tested patients. The APB muscle was most commonly involved in EMG. Among radiologic criteria, focal stenosis of subclavian artery in CTA was the most common finding.

CONCLUSION

We confirmed that TN-TOS is T1 predominant lower roots/trunk brachial plexopathy with clinical and electrodiagnostic features. Radiologic studies may be used to detect structural abnormalities.

SIGNIFICANCE

As MABC NCS showed abnormal results in all tested patients, it should be added to electrodiagnostic study as screening method. If present, structural abnormalities might be confirmed with radiologic studies.

Thoracic outlet syndrome presenting with subclavian vein thrombosis

Thoracic outlet syndrome can present with a wide variety of upper extremity neurovascular symptoms. Timely clinical recognition is essential for prompt treatment and maximal recovery. This article describes a case of thoracic outlet syndrome in a volleyball player with an underlying hypercoagulable state who presented with a subclavian vein thrombosis.

Magnetic resonance imaging of traumatic and non-traumatic brachial plexopathies

Adult-onset brachial plexopathy can be classified into traumatic and non-traumatic aetiologies. Traumatic brachial plexopathies can affect the pre- or postganglionic segments of the plexus. Non-traumatic brachial plexopathies may be due to neoplasia, radiotherapy, thoracic outlet syndrome and idiopathic neuralgic amyotrophy. Conventional magnetic resonance imaging (MRI) is useful to localise the area of injury or disease, and identify the likely cause. This review discusses some of the common causes of adult-onset brachial plexopathy and their imaging features on MRI. We also present a series of cases to illustrate some of these causes and their MRI findings.

Spectrum of suprascapular nerve lesions: normal and abnormal neuromuscular imaging appearances on 3-T MR neurography

OBJECTIVE. In this article, we will review the normal anatomy and imaging features of various neuromuscular abnormalities related to suprascapular neuropathy. CONCLUSION. Suprascapular neuropathy can be difficult to distinguish from rotator cuff pathology, plexopathy, and radiculopathy. Electrodiagnostic studies are considered the reference standard for diagnosis; however, high-resolution 3-T MR neurography (MRN) can play an important role. MRN enables direct visualization of the nerve and simultaneous assessment of the cervical spine, brachial plexus, and rotator cuff.