Magnetic Resonance Neurography in a Patient with Distal Neuralgic Amyotrophy

Nagao, Ryunosuke; Ishikawa, Tomomasa; Mizutani, Yasuaki; Niimi, Yoshiki; Shima, Sayuri; Ito, Mizuki; Murayama, Kazuhiro; Toyama, Hiroshi; Ueda, Akihiro; Watanabe, Haruo

doi:10.2169/internalmedicine.6440-20

Cited by 3 publications

(4 citation statements)

References 10 publications

(18 reference statements)

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“…Studies have shown that after treatment, with the relief of symptoms, the signal intensity of the injured nerve on MRN decreases but is still higher than that of peripheral normal nerves. [ 12 , 13 ] A follow-up patient in this group also showed similar performance in Figure 2 . According to literature reports, clinical follow-up of NA patients found that some patients improved after treatment, but some patients had nerve paralysis, no signs of recovery, and surgical exploration showed thickened edema of the involved nerve, adhesion of peripheral fibers, and hourglass-like stenosis in some segments.…”

Section: Discussionsupporting

confidence: 60%

Neuralgic amyotrophy: sensitivity and specificity of magnetic resonance neurography in diagnosis: A retrospective study

Duan,

Zhao,

Liu

et al. 2023

Medicine

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Background: Neuralgic amyotrophy (NA) is a clinically acute or subacute disease. To study the characteristics of brachial plexus magnetic resonance neurography (MRN) in patients with NA, and to explore the clinical application value of MRN combined with electromyography (EMG) in the diagnosis of NA. Methods: Brachial plexus MRN images of 32 patients with NA were retrospectively analyzed, and their characteristics were investigated. The accuracy, sensitivity and specificity of MRN, EMG, and the combination of the 2 methods for NA diagnosis were compared. Results: Among the 32 patients with NA, 28 (87.5%) cases of unilateral brachial plexus involvement, 18 (56.3%) cases of multiple nerve roots involvement. In 10 cases, C5 nerve roots were involved alone, and in 9 cases, C5 to C6 nerve roots were involved together. The T2 signal intensity of the affected nerve increased, and 19 cases showed thickened and smooth nerve root edges. Twelve cases showed uneven thickening and segmental stenosis of the involved nerve roots. The diagnostic accuracy, sensitivity, and specificity of MRN for NA were higher than those of EMG. Combining MRN and EMG could improve the sensitivity and specificity of diagnosis. Conclusion: The main feature of MRN in patients with NA was that it was unilateral brachial plexus asymmetric involvement. The diagnostic effect of MRN was better than that of EMG. The combined diagnosis of MRN and EMG can help clinicians diagnose NA accurately.

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Section: Discussionsupporting

confidence: 60%

Neuralgic amyotrophy: sensitivity and specificity of magnetic resonance neurography in diagnosis: A retrospective study

Duan,

Zhao,

Liu

et al. 2023

Medicine

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“…Hourglass-like constrictions (HGCs) of involved nerves in NA have been identified for almost 75 y during surgical exploration, 4,8 with histology revealing complete loss of myelinated fibers at the HGC site. 4,9 More recently, HGCs have been detected by ultrasound 14,15 and magnetic resonance neurography (MRN) [10][11][12] and are defined either as a focally reduced caliber 11 or diffusely beaded appearance of the nerve. 13 In a study of 35 subjects with NA, 84% were found by MRN to have HGCs 16 ; in another study, fascicular constrictions were observed in all subjects studied with MRN and in 88% subjects studied with ultrasound.…”

Section: Introductionmentioning

confidence: 99%

“…13 In a study of 35 subjects with NA, 84% were found by MRN to have HGCs 16 ; in another study, fascicular constrictions were observed in all subjects studied with MRN and in 88% subjects studied with ultrasound. 10 While additional anecdotal reports describe HGCs on MRN in NA, 14 the sensitivity of MRN to HGCs has not yet been reported in larger NA cohorts (>100) that have also been objectively assessed by EMG. This retrospective study aimed to determine, among a large cohort of patients with NA, whether MRN-detected HGCs are sensitive to cases of NA corroborated by EMG.…”

Section: Introductionmentioning

confidence: 99%

Hourglass‐like constrictions on MRI are common in electromyography‐confirmed cases of neuralgic amyotrophy (Parsonage–Turner syndrome): A tertiary referral center experience

Sneag,

Urban,

et al. 2023

Muscle and Nerve

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Introduction/AimsHourglass‐like constrictions (HGCs) of involved nerves in neuralgic amyotrophy (NA) (Parsonage–Turner syndrome) have been increasingly recognized with magnetic resonance neurography (MRN). This study sought to determine the sensitivity of HGCs, detected by MRN, among electromyography (EMG)‐confirmed NA cases.MethodsThis study retrospectively reviewed records of patients with the clinical diagnosis of NA, and with EMG confirmation, who underwent 3‐Tesla MRN within 90 days of EMG at a single tertiary referral center between 2011 and 2021. “Severe NA” positive cases were defined by a clinical diagnosis and specific EMG criteria: fibrillation potentials or positive sharp waves, along with motor unit recruitment (MUR) grades of “discrete” or “none.” On MRN, one or more HGCs, defined as focally decreased nerve caliber or diffusely beaded appearance, was considered “imaging‐positive.” Post hoc inter‐rater reliability for HGCs was measured by comparing the original MRN report against subsequent blinded interpretation by a second radiologist.ResultsA total of 123 NA patients with 3‐Tesla MRN performed within 90 days of EMG were identified. HGCs were observed in 90.2% of all NA patients. In “severe NA” cases, based on the above EMG criteria, HGC detection resulted in a sensitivity of 91.9%. Nerve‐by‐nerve analysis (183 nerve‐muscle pairs, nerves assessed by MRN, muscles assessed by EMG) showed a sensitivity of 91.0%. The second radiologist largely agreed with the original HGC evaluation, (94.3% by subjects, 91.8% by nerves), with no significant difference between evaluations (subjects: χ2 = 2.27, P = .132, nerves: χ2 = 0.98, P = .323).DiscussionMRN detection of HGCs is common in NA.

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“…If no clinical signs of recovery are noted in 3 months, magnetic resonance neurography is recommended. 35,39 If nerve constriction is revealed, surgery can be considered. If the percentage of nerve thinning caused by nerve constriction is less than 75%, intrafascicular neurolysis is recommended.…”

Section: Treatmentmentioning

confidence: 99%

Neuralgic amyotrophy: an underrecognized entity

Kim

Lee

2021

J Int Med Res

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Neuralgic amyotrophy (NA) is markedly underdiagnosed in clinical practice, and its actual incidence rate is about 1 per 1000 per year. In the current article, we provide an overview of essential information about NA, including the etiology, clinical manifestations, diagnostic investigations, differential diagnosis, treatment, and prognosis. The causes of NA are multifactorial and include immunological, mechanical, or genetic factors. Typical clinical findings are a sudden onset of pain in the shoulder region, followed by patchy flaccid paralysis of muscles in the shoulder and/or arm. A diagnosis of NA is based on a patient’s clinical history and physical examination. Gadolinium-enhanced magnetic resonance imaging and high-resolution magnetic resonance neurography are useful for confirming the diagnosis and choosing the appropriate treatment. However, before a diagnosis of NA is confirmed, other disorders with similar symptoms, such as cervical radiculopathy or rotator cuff tear, need to be ruled out. The prognosis of NA depends on the degree of axonal damage. In conclusion, many patients with motor weakness and pain are encountered in clinical practice, and some of these patients will exhibit NA. It is important that clinicians understand the key features of this disorder to avoid misdiagnosis.

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Magnetic Resonance Neurography in a Patient with Distal Neuralgic Amyotrophy

Cited by 3 publications

References 10 publications

Neuralgic amyotrophy: sensitivity and specificity of magnetic resonance neurography in diagnosis: A retrospective study

Neuralgic amyotrophy: sensitivity and specificity of magnetic resonance neurography in diagnosis: A retrospective study

Hourglass‐like constrictions on MRI are common in electromyography‐confirmed cases of neuralgic amyotrophy (Parsonage–Turner syndrome): A tertiary referral center experience

Neuralgic amyotrophy: an underrecognized entity

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