Neuralgic amyotrophy detected by magnetic resonance neurography: subclinical, bilateral, and multifocal brachial plexus involvement.

INTRODUCTION: Neuralgic amyotrophy (NA) is a painful non-traumatic peripheral nervous system condition affecting the brachial plexus. Signal abnormalities in nerves and muscles have been detected in these patients using magnetic resonance neurography (MRN). METHODS: Electronic medical records and MRN images obtained in a 3 T scanner, in 14 adult patients diagnosed with NA at our Neurological institution (Neuromuscular Disorders Section), between December 2015 and December 2019 were retrospectively reviewed. The study was first approved by our Institutional Ethics Committee. RESULTS: Subclinical, multifocal, and bilateral nerve signal anomalies were recorded in the brachial plexus of these patients. We identified four different types of nerve constriction without entrapment, which we categorized as follows: incomplete focal (type I), complete focal or hourglass (type II), multifocal or string of pearls (type III) and segmental (type IV). CONCLUSIONS: Given that MRN is an accurate diagnostic tool to detect nerve damage, we believe abnormal findings could improve early detection of NA patients.

Lumbosacral plexus root thickening: Establishing normal root dimensions using magnetic resonance neurography.

Disorders affecting the lumbosacral plexus (LSP) can alter root diameter. Our aim was to determine normal LSP nerve root dimensions using magnetic resonance neurography (MRN). Eleven asymptomatic patients (ages: 18-53, mean: 34 years) underwent MRN of the LSP on a 3 T scanner with an 8-channel torso-PA coil. IDEAL T2-weighted images were acquired and nerve root dimensions were measured from the second lumbar (L2) to the first sacral (S1) vertebrae on the coronal plane, 5 mm from the dorsal root ganglion (DRG). Root size was recorded by three separate groups of radiologists with different levels of expertise. Additional LSP-MRN images were acquired from a fresh-frozen cadaver specimen using the same scanner and parameters identical to those described above. Subsequently, two experienced anatomists dissected and measured the LSP roots at exactly the same distance from the DRG, using an electronic caliper. Mean root size values recorded (± standard deviation) in the asymptomatic patients were as follows: L2: 3.12 mm (±0.92), L3: 4.29 mm (±0.95), L4: 5.13 mm (±0.79), L5: 5.29 mm (±0.9), and S1: 5.38 mm (±0.7). The correlation coefficients were 0.72 between the patient and cadaver MRN results and 0.79 between the patient and dissected cadaver MRN results. Inter-observer agreements were 0.73 among the radiologist groups and 0.87 between the anatomists conducting dissections. We believe MRN provides reliable assessments of LSP root thickness. More extensive studies should be conducted to confirm the results described here. Clin. Anat. 31:782-787, 2018. © 2018 Wiley Periodicals, Inc.

Intraneural perineuriomas: diagnostic value of magnetic resonance neurography.

Intraneural perineurioma (IP) is an under-recognized hypertrophic peripheral nerve tumor. It affects young patients involving frequently the sciatic nerve and its branches and presents with a progressive, painless and predominantly motor deficit. Magnetic resonance neurography (MRN) is a useful tool to localize the lesion, evaluate its extension, and discriminate between different etiologies. We reviewed the clinical records of 11 patients with pathologically confirm IP. Eight patients were males with mean age 19 years. Initial complains were unilateral steppage (seven patients), bilateral steppage (one patient), unilateral gastrocnemius wasting (one patient), unilateral thigh atrophy (one patient), and unilateral hand weakness (one patient). Nine patients had mild painless sensory loss. Examinations revealed involvement of sciatic nerve extending into the peroneal nerve (eight patients), posterior tibial nerve (one patient), radial nerve (one patient), and femoral nerve (one patient). MRN revealed enlargement of the affected nerve isointense on T1-weighted, hyperintense on T2 fat-saturated images, and with avid enhancement on post-contrast imaging. In all patients, a nerve biopsy confirmed the diagnosis. MRN allows early and non-invasive identification of this tumor and is a key tool providing localization and differential diagnosis in patients with slowly progressive focal neuropathies.

The role of magnetic resonance imaging in the evaluation of peripheral nerves following traumatic lesion: where do we stand?

BACKGROUND: Peripheral nerve injury is a common and important cause of morbidity and disability in patients who have suffered a traumatic injury, particularly younger people. Various different injuries can result in damage to specific nerves. In patients with multiple trauma, the prevalence of peripheral nerve injury is estimated at 2.8%, but can reach 5% with the inclusion of brachial plexus involvement. Physical examination, as well as the origin and location of the trauma, can indicate the nerve involved and the type of nerve damage. However, the depth and severity of damage, and the structures involved often cannot be determined initially, but depend on longer periods of observation to reach a definitive and accurate diagnosis for which treatment can be proposed. Current approaches to locate and assess the severity of traumatic nerve injury involve clinical and electrodiagnostic studies. From a clinical and neurophysiological point of view, nerve injuries are classified in an attempt to correlate the degree of injury with symptoms, type of pathology, and prognosis, as well as to determine the therapy to be adopted. OBJECTIVES: MRI in the diagnosis of traumatic peripheral nerve injury has increasingly been used by surgeons in clinical practice. In this article, we analyze the use of magnetic resonance (MR) for the evaluation of traumatic peripheral nerve diseases that are surgically treatable. We also consider basic concepts in the evaluation of technical and MR signs of peripheral nerve injuries. MATERIALS AND METHODS: Studies were identified following a computerized search of MEDLINE (1950 to present), EMBASE (1980 to present), and the Cochrane database. The MEDLINE search was conducted on PUBMED, the EMBASE search was conducted on OVID, and the Cochrane database was conducted using their online library. A set was created using the terms: 'traumatic', 'nerve', and 'resonance'. RESULTS: The included articles were identified using a computerized search and the resulting databases were then sorted according to the inclusion and exclusion criteria. This yielded 10,340 articles (MEDLINE, n = 758; EMBASE, n = 9564; and Cochrane, n = 18). A search strategy was then built by excluding articles that only concern plexus injury and adding the terms 'neuropathies', 'DTI' and 'neurotmesis'. In total, seven studies were included in the review effectively addressing the role of MRI in the evaluation of traumatic peripheral nerve injury. We extracted all relevant information on the imaging findings and the use of magnetic resonance in trauma. We did not include technical or specific radiological aspects of the imaging techniques. CONCLUSIONS: These seven articles were subsequently evaluated by analyzing their results, methodological approach, and conclusions presented.