Magnetic Resonance Neurography Findings Research Articles

Whole-body magnetic resonance neurography in patients with chronic inflammatory demyelinating polyneuropathy.

Whole-body magnetic resonance neurography (MRN) is an imaging modality that shows peripheral nerve signal change in patients with chronic inflammatory demyelinating polyneuropathy (CIDP). We aimed to explore the diagnostic potential of whole-body MRN and its potential as a monitoring tool after immunotherapy in treatment-naïve CIDP patients. Whole-body MRN using coronal 3-dimensional short tau inversion recovery (STIR) sampling perfection with application-optimized contrasts by using different flip angle evolution (SPACE) techniques was performed in patients being investigated for CIDP and in healthy controls. Baseline clinical neuropathy scales and electrophysiologic parameters were collected, and MRN findings were compared before and after CIDP treatment. We found highly concordant symmetrical thickening and increased T2 signal intensities in the brachial/lumbosacral plexus, femoral, or sciatic nerves in five of the eight patients with a final diagnosis of CIDP and none of the healthy controls. There were no treatment-related imaging changes in five patients with CIDP who completed a follow-up study. Diffuse, symmetrical thickening, and increased T2 signal in root, plexus, and peripheral nerves were found in two patients ultimately excluded due to a diagnosis of polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, skin changes (POEMS) syndrome in addition to signal changes in the muscles, bony lesions, organomegaly, and lymphadenopathy. Whole-body MRN imaging shows promise in detecting abnormalities in proximal nerve segments in patients with CIDP. Future studies evaluating the role of MRN in assessing treatment response should consider follow-up scans after treatment durations of more than 4 months.

The original nerve of a greater occipital nerve schwannoma causing occipital neuralgia identified with magnetic resonance neurography

Schwannomas are benign tumors arising from Schwann cells in the peripheral nerve and rarely develop at suboccipital area. We report a case of a greater occipital nerve schwannoma causing occipital neuralgia. The original nerve of the schwannoma was identified with Magnetic Resonance (MR) neurography. A sixty-something male patient was admitted for a suboccipital mass. Physical examination revealed an about 4 cm beaded masses subcutaneously at suboccipital area. MR imaging showed that the lesions were not suppressed on 3 dimensional T2 weighting with fat suppression. Three dimensional fusion images (3 dimensional T2 weighting with fat suppression and 3-dimensional computed tomography) clearly revealed the original nerve of the lesions. The patient underwent a complete excision on the tumor. Histopathological examination diagnosed it as a schwannoma. The MR neurography findings contributed to preoperatively diagnose the tumors as a greater occipital nerve schwannoma.

The value of magnetic resonance neurography in evaluation of sciatic neuropathy

BackgroundSciatic neuropathy is one of the most common neuropathies of the lower extremities. One of the most common presentations of sciatic neuropathy is foot drop and may also be associated with several other clinical (sensory and/or motor) presentations. In recent years, magnetic resonance imaging (MRI) has established itself as an important tool for the study of peripheral nerves, especially after the development of protocols including sequences optimized for this purpose, referred to as magnetic resonance neurography (MRN), being used as noninvasive means of diagnosing peripheral nerve disease. Such high-resolution imaging protocols aimed to image the nerves at hip, thigh, knee, leg, ankle, and foot and can demonstrate traumatic or iatrogenic injury, tumor-like lesions, or entrapment of the nerves, causing a potential loss of motor and sensory function in the affected area. This study aimed to be familiar with MRI and MRN findings in patients with sciatic neuropathy.ResultsIn this prospective study, thirty patients presented with clinical manifestations and/or electrophysiological studies having sciatic neuropathy and underwent MRI and MRN at a university Hospital from March 2021 to March 2022. In view of clinical presentation, muscle weakness (66.67%), numbness and tingling (60%), and sensory manifestation (60%) were the most prevalent presenting manifestation followed by back pain (43.33%), foot drop (33.33%), and urinary and bowel incontinence (23.33%). MRN and MRI results showed a strong correlation with the presenting symptoms of participants, in the form of increased sciatic nerve caliber in 23.33%, muscular atrophy in 13.33%, nerve root impingement in 26.67%, and lumbar spondylosis in 36.67%. MR neurography sequences gave additional findings to the conventional MRI in the form of increased nerve signal intensity in 53.33%, perineural edema in 50% of cases, neural structure disruption in 26.67%, muscular impend denervation in 16.67%, bone marrow edema in 30.33%, pseudo-meningocele in 13.33%, and nerve root avulsion in 3.33% with no correlated findings in MRI.ConclusionsMRN is an additional accurate tool in the study of different sciatic nerve diseases and can also give detailed knowledge of the nerve anatomy, adding value to electrophysiological studies and conventional MRI.

Prospective pre-operative 3-T MR neurography peripheral nerve mapping of upper extremity amputations implanted with FAST-LIFE electrode interfaces of robotic hands: technical report.

Fascicular targeting of longitudinal intrafascicular electrode (FAST-LIFE) interface enables hand dexterity with exogenous electrical microstimulation for sensory restoration, custom neural recording hardware, and deep learning-based artificial intelligence for motor intent decoding. The purpose of this technical report from a prospective pilot study was to illustrate magnetic resonance neurography (MRN) mapping of hand and nerve anatomy in amputees and incremental value of MRN over electrophysiology findings in pre-surgical planning of FAST-LIFE interface (robotic hand) patients. After obtaining informed consent, patients with upper extremity amputations underwent pre-operative 3-T MRN, X-rays, and electrophysiology. MRN findings were correlated with electrophysiology reports. Descriptive statistics were performed. Five patients of ages 21-59years exhibited 3/5 partial hand amputations, and 2/5 transradial amputations on X-rays. The median and ulnar nerve end bulb neuromas measured 10.1 ± 3.04mm (range: 5.5-14mm, median: 10.5mm) and 10.9 ± 7.64mm (2-22mm, 9.75mm), respectively. The ADC of median and ulnar nerves were increased at 1.64 ± 0.1 × 10-3 mm2/s (range: 1.5-1.8, median: 1.64 × 10-3 mm2/s) and 1.70 ± 0.17 × 10-3 mm2/s (1.49-1.98 × 10-3 mm2/s, 1.65 × 10-3 mm2/s), respectively. Other identified lesions were neuromas of superficial branch of the radial nerve and anterior interosseous nerve. On electrophysiology, 2/5 reports were unremarkable, 2/5 showed mixed motor-sensory neuropathies of median and ulnar nerves along with radial sensory neuropathy, and 1/5 showed sensory neuropathy of lateral cutaneous nerve of the forearm. All patients regained naturalistic sensations and motor control of digits. 3-T MRN allows excellent demonstration of forearm and hand nerve anatomy, altered diffusion characteristics, and their neuromas despite unremarkable electrophysiology for pre-surgical planning of the FAST-LIFE (robotic hand) interfaces.

3-T MR neurography of lumbo-sacral plexus in hereditary transthyretin-related amyloidosis with polyneuropathy.

Our aim was to evaluate the ability of magnetic resonance neurography (MRN) of the lumbo-sacral plexus (LSP) to distinguish patients with hereditary transthyretin-related amyloidosis with polyneuropathy (ATTRv-PN) from asymptomatic variant carriers (AVC) and healthy controls and to assess its prognostic value. Three-Tesla MRN was performed in 25 consecutive ATTRv-PN patients, 18 AVC, and 10 controls including T2-w DIXON and DWI MR sequences. Two blinded readers independently assessed LSP root diameter and intraneural signal on the MRN images of each subject. MRN findings were compared between groups and correlated with clinical impairment scored on the Neuropathy Impairment Score (NIS) and the modified Polyneuropathy Disability score (mPND). The agreement between readers on MRN images was excellent (Cohen's kappa = 0.82). LSP root enlargement was significantly more frequent in ATTRv-PN patients compared to AVC (ratio = 4.38, p = 0.038). Increased LSP root intraneural signal on T2-w images was significantly more frequent in ATTRv-PN patients compared to AVC (ratio = 3.4, p = 0.016). In contrast, there were no MRN abnormalities in controls. In ATTRv-PN patients, LSP root enlargement was associated with higher mPND scores (p = 0.03) and increased intraneural signal on T2-w images was associated with significantly higher NIS and mPND scores (p = 0.004 and 0.02, respectively). MRN of the LSP can help differentiate ATTRv-PN patients from AVC. LSP root enlargement and increased intraneural signal are significantly associated with clinical impairment, suggesting potential implications for patient care. • ATTRv-PN patients showed abnormal LSP changes on MRN. • MRN of the LSP can help to differentiate ATTRv-PN patients from AVC and healthy controls. • LSP root enlargement and increased intraneural signal were significantly associated with clinical impairment in ATTRv-PN patients.

Additive value of magnetic resonance neurography in diagnosis of brachial plexopathy: a cross-section descriptive study

BackgroundManagement of brachial plexopathy requires proper localization of the site and nature of nerve injury. Nerve conduction studies and electrophysiological studies (ED) are crucial when diagnosing brachial neuropathy but these do not determine the actual site of the lesion. Conventional MRI has been used to evaluate the brachial plexus. Still, it carried the disadvantage of the inability to provide multi-planar images that depict the entire length of the neural plexus .It might be difficult to differentiate the brachial plexus nerves from adjacent vascular structures. Magnetic resonance neurography (MRN) is an innovative imaging technique for direct imaging of the spinal nerves. Our study aims to detect the additive role of MRN in the diagnosis of brachial plexopathy over ED. Forty cases of clinically suspected and proved by clinical examination and ED—traumatic (N = 30) and non-traumatic (N = 10)—were included in our study. We compared MRN finding with results of clinical examination and ED.ResultsMRN findings showed that the root was involved in 80% of cases, trunks in 70% of cases affecting the middle trunk in 40% of cases, the middle and posterior cord in 25%, lateral cord in 50%, and terminal branches on 10% of cases. Ten percent of cases were normal according to MRN, and 90% had abnormal findings in the form of preganglionic nerve root avulsion in 30% of cases, mild perineural edema surrounding C6/7 nerve roots in 20%, lower brachial trunk high signal in 10%, complicated with pseudo meningocele in 20%, and with increased shoulder muscle T2 signal intensity with muscle atrophy in 10%. There were minimal differences between clinical examination finding and MRN findings, with very good agreement between electromyography and nerve conduction (p value < 0.05, with sensitivity and specificity values of 94.44% and 100%, respectively).ConclusionMRN is important in differentiating different types of nerve injuries, nerve root avulsion, and nerve edema, playing an important role in differentiating the site of nerve injury, both preganglionic or postganglionic and planning for treatment of the cause of nerve injury, either medical or surgical.

Does Presurgical Magnetic Resonance Neurography Predict Surgical Gap Size in Trigeminal Class IV and V Injuries?

The accuracy of magnetic resonance neurography (MRN) for quantitative assessment of nerve injury gap is unknown. We tested the hypothesis that presurgical MRN predicts the final surgical gap size after neuroma resection at the time of surgery. This was a retrospective, single-blinded, nonrandomized cohort study on 43 patients with Sunderland Class IV and V injuries of the inferior alveolar (IAN) or the lingual nerve (LN). The MRN maxillofacial protocol was performed on a 3T scanner and was read by 2 musculoskeletal radiologists to determine the maximum size of neuroma and the abnormal nerve segment. Two independent variables were recorded during surgery: 1) the length of neuroma from histologic specimens since only 9 of the 43 neuroma size measurements were accurately measureable at the time of surgery; and 2) the length of nerve gap size after the neuroma was removed and normal fascicles were identified. There were 7 IAN and 36 LN cases analyzed. The mean time in months from injury to MRN was 6.97 ± 9.18 and MRN to surgery was 1.21 ± 1.4. The mean length of the neuroma at surgery was 7.22 ± 2.78 mm and mean nerve gap size was 12.02 ± 4.41 mm. Intraclass coefficient (ICC) agreement was fair for abnormal nerve thickness and neuroma length (ICC=0.28, 0.39) while it was moderate for neuroma thickness and abnormal nerve length (0.50, 0.59). There was no significant correlation between MRN based measurements and surgical gap size for both readers (P > .05). Abnormal nerve and neuromas of the peripheral trigeminal nerve as identified on MRN imaging demonstrates no correlation of the assessed MRN findings with the final surgical gap after neuroma removal.

Characteristics of Patients With Complex Limb Pain Evaluated Through an Interdisciplinary Approach Utilizing Magnetic Resonance Neurography.

Patients with persistent complex limb pain represent a substantial diagnostic challenge. Physical exam, and tests such as nerve conduction, are often normal even though the patient suffers from severe pain. In 2015, we initiated a team-based approach to evaluate such patients. The approach included physicians from several specialties (Anesthesiology/Pain Medicine, Radiology, Plastic Surgery, Neurosurgery) combined with the use of advanced imaging with Magnetic Resonance Neurography (MRN). This preliminary case series discusses MRN findings identified in patients with previously difficult-to-diagnose peripheral limb pain and describes how this combination of approaches influenced our diagnosis and treatment plans. We extracted demographics, patient characteristics, presenting features, diagnostic tests performed, treatments provided, referral diagnosis and the diagnosis after interdisciplinary team evaluation from patient charts. We evaluated MRN and electrodiagnostic studies (EDX) ability to identify injured nerves. We compared abnormal findings from these diagnostics to patient reported outcome after ultrasound-guided nerve block. A total of 58 patients, 17 males and 41 females, were identified. The majority of patients presented with lower extremity pain (75%) and had prior surgery (43%). The most commonly identified abnormality on MRN was nerve signal alteration on fluid sensitive sequences, followed by caliber change and impingement. Comparing the outcome of diagnostic nerve blocks with abnormal nerve findings on MRN or EDX, we found that MRN had a sensitivity of 67% and specificity of 100% while for EDX it was 45 and 0%, respectively. After interdisciplinary discussion and imaging review, a more specific diagnosis was produced in 78% of evaluated cases opening up additional treatment pathways such as nerve-targeted surgery, which was performed in 36% cases. This descriptive case series demonstrates that a majority of patients evaluated by our team for complex limb pain were women with lower extremity pain resulting from surgery. In addition, an interdisciplinary team evaluation and the use of the moderately sensitive but highly specific MRN imaging modality resulted in a change in diagnosis for a majority of patients with complex limb pain. Future studies investigating patient outcomes after diagnosis change are currently underway based on the findings of this preliminary study.

Long-Segment Peripheral Neuropathies after COVID-19: Magnetic Resonance Neurography Findings (4645)

Long-Segment Peripheral Neuropathies after COVID-19: Magnetic Resonance Neurography Findings (4645)

Magnetic resonance neurography findings in three critically ill COVID-19 patients with new onset of extremity peripheral neuropathy

PurposeCoronavirus-19 (COVID-19) is most commonly associated with respiratory syndromes, although patients are presenting more frequently with neurological symptoms. When they occur, neurological conditions most commonly involve the central nervous system, and peripheral nervous system effects, particularly in the extremities, have been less commonly described. The mechanisms of peripheral neuropathy in critically ill patients with COVID-19 are likely to be multifactorial, and extremity peripheral nerve imaging in these cases has not been well described.Case presentationIn this case series, we describe the magnetic resonance neurography (MRN) findings in 3 critically ill patients who presented with new onset of peripheral neuropathies in the extremities, and we discuss possible common mechanisms of nerve injury, including the role of position-related nerve injury.ConclusionsMRN can be useful in identifying and localizing peripheral nerve abnormalities in the extremities of COVID-19 patients, and patients who are placed in the prone position during ventilation may be more susceptible to these injuries.

Role of 3 Tesla MR Neurography and CT-guided Injections for Pudendal Neuralgia: Analysis of Pain Response

Background: Magnetic resonance neurography (MRN) has an increasing role in the diagnosis and management of pudendal neuralgia, a neurogenic cause of chronic pelvic pain. Objective: The objective of this research was to determine the role of MRN in predicting improved pain outcomes following computed tomography (CT)-guided perineural injections in patients with pudendal neuralgia. Study Design: This study used a retrospective cross-sectional study design. Setting: The research was conducted at a large academic hospital. Methods: Patients: Ninety-one patients (139 injections) who received MRN and CT-guided pudendal blocks were analyzed. Intervention: A 3Tesla (T) scanner was used to evaluate the lumbosacral plexus for pudendal neuropathy. Prior to receiving a CT-guided pudendal perineural injection, patients were given pain logs and asked to record pain on a visual analog scale. Measurement: MRN findings for pudendal neuropathy were compared to the results of the CTguided pudendal nerve blocks. Injection pain responses were categorized into 3 groups – positive block, possible positive block, and negative block. Statistical Tests: A chi-square test was used to test any association, and a Cochran-Armitage trend test was used to test any trend. Significance level was set at .05. All analyses were done in SAS Version 9.4 (SAS Institute, Inc., Cary, NC). Results: Ninety-one patients (139 injections) who received MRN were analyzed. Of these 139 injections, 41 were considered positive (29.5%), 52 of 139 were possible positives (37.4%), and 46 of 139 were negative blocks (33.1%). Of the patients who had a positive pudendal block, no significant difference was found between the MRN result and the pudendal perineural injection response (P = .57). Women had better overall response to pudendal blocks, but this response was not associated with MRN findings (P = .34). However, positive MRN results were associated with better pain response in men (P = .005). Patients who reported bowel dysfunction also had a better response to pudendal perineural injection (P = .02). Limitations: Some limitations include subjectivity of pain reporting, reporting consistency, absence of a control group, and the retrospective nature of the chart review. Conclusion: Pudendal perineural injections improve pain in patients with pudendal neuralgia and positive MRN results are associated with better response in men. Key words: MRI, MRN, CT injection, pudendal neuralgia, pudendal nerve, pelvic pain, chronic pelvic pain, pudendal neuropathy

MR neurography in traumatic, non-obstetric paediatric brachial plexopathy.

Many studies have elaborated on the role of magnetic resonance neurography (MRN) in evaluating traumatic brachial plexopathies. Most of these deal with MR findings in adult traumatic plexopathies or children with obstetric brachial plexus palsy (OBPP). Hence, the authors felt the need for this particular study, which focuses on MRN findings in children with non-obstetric traumatic brachial plexus palsy, to find out the distribution and severity of injuries in these patients. This was a single-institution, prospective study conducted between April 2015 and June 2016. All children presenting to the hospital with features of brachial plexopathy and a history of non-obstetric trauma were included in the study. At MRN, we looked for signs of injury at three levels: roots, trunks and cords. Signs of injury were found at the level of the roots in 22 patients (88%), at the level of the trunks in 20 patients (80%) and at the level of the cords in 22 patients (88%). This study, conducted on children suffering from non-obstetric, traumatic brachial plexopathy returned some interesting conclusions including that when the paediatric plexus is injured, the injury is severe and multi-level, with a very high incidence of root injuries. • Brachial plexus injury in paediatric age group is a devastating injury. • The most common cause of this is trauma sustained during birth. • Other causes include road traffic accidents and blunt injury. • MR neurography has revolutionised the diagnosis of brachial plexopathy.

Magnetic Resonance Neurography of Traumatic and Nontraumatic Peripheral Trigeminal Neuropathies

The clinical neurosensory testing (NST) is currently the reference standard for the diagnosis of traumatic and nontraumatic peripheral trigeminal neuropathies (PTNs), but exhibits both false-positive and false-negative results compared with surgical findings and frequently results in treatment decision delays. We tested the hypothesis that magnetic resonance neurography (MRN) of PTNs can serve as a diagnostic modality by correlating the NST, MRN, and surgical findings. Sixty patients with traumatic and nontraumatic PTN of varying etiologies and Sunderland classifications underwent NST, followed by MRN using 1.5T and 3.0T scanners. The protocol included 2-dimensional and 3-dimensional (3D) imaging, including diffusion imaging and isotropic 3D PSIF. The MRN findings were read by 2 readers in consensus with the clinical findings but without knowing the side of abnormality. The MRN results were summarized using the Sunderland classification. In 26 patients, surgery was performed, and the Sunderland classification was assigned using the surgical photographs. Agreement between the MRN findings and NST/surgical classification was evaluated using kappa statistics. Pearson's correlation coefficient was used to assess the correlation between continuous measurements of MRN/NST and surgical classification. Of the 60 patients, 19 males and 41 females, mean age 41years (range 12 to 75), with 54 complaints of altered sensation of the lip, chin, or tongue, including 16 with neuropathic pain and 4 with no neurosensory complaint, were included. Third molar surgery (n=29) represented the most common cause of traumatic PTN. Assuming 1 nerve abnormality per patient, the lower class was accepted, a kappa of 0.57 was observed between the MRN and NST classification. A kappa of 0.5 was found between MRN and surgical findings with a Pearson correlation coefficient of 0.67. MRN anatomically maps PTNs and stratifies the nerve injury and neuropathies with moderate to good agreement with NST and surgical findings for clinical use.

Magnetic Resonance Neurography of the Lumbosacral Plexus in Failed Back Surgery Syndrome.

Retrospective clinical case series. To study the role of magnetic resonance neurography (MRN) of the lumbosacral plexus in management of patients with failed back surgery syndrome (FBSS). FBSS is one of the major problems in health care, affecting up to 40% of patients after spine surgery. To date, no imaging modality has been used to effectively classify nerve compression, because nerve injuries are challenging to detect on conventional lumbar spine magnetic resonance imaging (MRI). To our knowledge, no previous studies have addressed the use of MRN in FBSS or compared it to lumbar spine MRI. From 203 consecutive 3 T MRN studies of lumbosacral plexus in 1 year, 12% (25/203) presented as FBSS. Demographic data, number of previous lumbar MRIs and their findings, MRN findings, interval between MRI and MRN, pre-and post-MRN diagnosis, pain levels, and treatments were recorded. Changes in diagnosis, treatment, and outcomes after MRN were determined. The final sample of 25 patients had a mean age 62 ± 15 and male to female ratio 1:1.08. Approximately 88% (22/25) had previous lumbar MRI, of which 27% had 3 or more. Most common imaging findings were neuroforaminal stenosis 22.6% (7/31) on MRI and neuropathy 22.9% (19/83) on MRN. Mean interval between MRI and MRN was 13.9 ± 28.3 months. Lumbar MRIs were inconclusive in 36% (8/22). MRN detected 63% (52/83) more findings and changed the diagnosis and treatment in 12% and 48% of FBSS cases, respectively. Favorable outcomes were recorded in 40% to 67% of patients following MRN-guided treatments. FBSS is a complex problem and MRN of lumbosacral plexus impacts its management by better directing source of symptoms. 4.

Does MR Neurography Parameters Predict or Correlate With Clinical Recovery in Severe Carpal Tunnel Syndrome

Hypothesis: Does magnetic resonance (MR) neurography parameters predict or correlate with clinical recovery in severe carpal tunnel syndrome (CTS). Methods: Subjects were prospectively collected 22 hands from 22 CTS patients, with abductor pollicis brevis-compound muscle action potential (APB-CMAP) of 2 mV or less and evaluated preoperatively and postoperatively for clinical, electrophysiological, and MR neurography findings to find out potential risk factors and predictors of thumb opposition recovery. Parameters observed in MR neurography were morphological changes in median and thenar branch of median nerve, median nerve diameter and width, carpal tunnel diameter, denervation edema, and bowing ratio. We considered more than 0.5 mV improvement in APB-CMAP postoperatively significant. Results: Two groups were made and compared for all postoperative variables. Group 1 had patients with less than 0.5 mV improvement and group 2 had more than 0.5 mV improvement. Demographic, MR neurogram variables, and functional score had better results in group 2 comparing with group 1 but were not statistically significant. Thumb opposition showed poor results in group 2 comparing with group 1 may be because clinical recovery lags electrophysiological recovery. We did not find any significant difference for duration of symptoms in 2 groups. Conclusion: In practical terms, we did not find any predictor in clinical and MR neurography variables that correlate with recovery of thumb opposition.

Recurrent ulnar nerve entrapment at the elbow: Correlation of surgical findings and 3-Tesla magnetic resonance neurography

The authors describe the correlation between 3-Tesla magnetic resonance neurography (MRN) and surgical findings in two patients who underwent multiple previous failed ulnar nerve surgeries. MRN correctly localized the site of the abnormality. Prospectively observed MRN findings of perineural fibrosis, ulnar nerve re-entrapment abnormalities, medial antebrachial cutaneous neuroma and additional median nerve entrapment were confirmed surgically.

Magnetic resonance neurography findings in herpetic brachial plexopathy

Brachial plexus neuritis was originally diagnosed by clinical signs and symptoms in addition to electrophysiological studies [1–5]. Therefore, initially, brachial plexopathy was misdiagnosed as a shoulder disorder, cervical radiculopathy, or myelopathy [4]. Herpes zoster brachioplexopathy is a rare complication characterized by motor weakness of the arm, which may occur in limbs affected by herpes zoster. Varicella zoster virus can induce inflammatory brachial plexopathy [1–4, 6]. It is still under-recognized by clinicians and misdiagnosis or delay in treatment can occur as a consequence. Magnetic resonance (MR) imaging studies have been attempted for diagnosis of brachial plexus disorders [6–9]. However, there are very few reports about MR neurography for zoster-induced brachial neuritis [6]. We present a 68-yearold male patient with monoparesis resulting from brachial plexopathy caused by varicella zoster virus infection and report the findings of MR neurography in this patient. A 68-year-old man noted a skin rash, vesicles, and pain in his left arm. At that time, he was not treated. Four days later, he developed weakness in his left arm and visited the emergency department at our hospital for this complaint. Upon admission, the patient had multiple erythematous crusted plaques on the left arm (Fig. 1). Neurologic examination revealed weakness of shoulder abduction (grade 2/5) and elbow flexion (grade 2/5), and the left biceps reflex was diminished. He had dysesthesia and hyperalgesia over the left C6–7 dermatomes. The level of IgG antibodies against varicella zoster virus was elevated. However, the IgM antibody level against varicella zoster was negative. We performed MR neurography of the brachial plexus with a 1.5-T MR imaging system (Gyroscan Intera, Philips Medical Systems, Netherlands) 10 days after admission. Among the MR neurography images, the coronal short tau inversion recovery (STIR, TR/TE: 3558.39/60.00, time inversion: 160 ms) image depicted edema and thickening of the superior trunk of the left brachial plexus compared to the unaffected right side (Fig. 2). MR imaging also showed denervation edema of the left supraspinatus muscle (Fig. 3). Needle electromyography showed fibrillations and positive sharp waves in the left deltoid and biceps muscles and only positive sharp waves in the left supraspinatus muscle. The patient was treated with intravenous acyclovir and physical therapy for his left arm. After discharge, he was followed in the outpatient department for 6 months. His left-arm weakness improved to grade 3. Herpes zoster brachial plexus neuritis-associated motor weakness may be due to a demyelinating process related to inflammation [1–3, 5, 6]. Inflammatory changes in the brachial plexus result in swelling and thickening of divisions or cords of the brachial plexus. MRI can demonstrate inflammatory changes in neural tissue and MR neurography can detect inflammatory changes in the brachial plexus and denervation edema of affected muscle [6–9]. Especially STIR images from MR neurography have been used for evaluation of pathological lesions of the brachial plexus such as neuralgic amyotrophy [7, 8]. In our case, we evaluated the STIR images of the brachial plexus and they D. H. Heo Y. J. Cho (&) Department of Neurosurgery, Peripheral Nerve Disorder Clinic, Chuncheon Sacred Heart Hospital, Hallym University Medical Center, 153 Kyo-dong, Chuncheon-shi, Kangwon-do, Korea e-mail: nssur771@hallym.or.kr

Magnetic resonance neurography in children with birth-related brachial plexus injury

Magnetic resonance neurography (MRN) enables visualization of peripheral nerves. Clinical examination and electrodiagnostic studies have been used in the evaluation of birth-related brachial plexus injury. These are limited in their demonstration of anatomic detail and severity of injury. We investigated the utility of MRN in evaluating birth-related brachial plexus injury in pediatric patients, and assessed the degree of correlation between MRN findings and physical examination and electromyographic (EMG) findings. The MRN findings in 11 infants (age 2 months to 20 months) with birth-related brachial plexus injury were evaluated. A neuroradiologist blinded to the EMG and clinical examination findings reviewed the images. Clinical history, examination, EMG and operative findings were obtained. All infants had abnormal imaging findings on the affected side: seven pseudomeningoceles, six neuromas, seven abnormal nerve T2 signal, four nerve root enlargement, and two denervation changes. There was greater degree of correlation between MRN and physical examination findings (kappa 0.6715, coefficient of correlation 0.7110, P < 0.001) than between EMG and physical examination findings (kappa 0.5748, coefficient of correlation 0.5883, P = 0.0012). MRN in brachial plexus trauma enables localization of injured nerves and characterization of associated pathology. MRN findings demonstrated a statistically significant correlation with physical examination and EMG findings, and might be a useful adjunct in treatment planning.