Optimized 3D brachial plexus MR neurography using deep learning reconstruction.

OBJECTIVE: To evaluate whether 'fast,' unilateral, brachial plexus, 3D magnetic resonance neurography (MRN) acquisitions with deep learning reconstruction (DLR) provide similar image quality to longer, 'standard' scans without DLR. MATERIALS AND METHODS: An IRB-approved prospective cohort of 30 subjects (13F; mean age = 50.3 ± 17.8y) underwent clinical brachial plexus 3.0 T MRN with 3D oblique-coronal STIR-T2-weighted-FSE. 'Standard' and 'fast' scans (time reduction = 23-48%, mean = 33%) were reconstructed without and with DLR. Evaluation of signal-to-noise ratio (SNR) and edge sharpness was performed for 4 image stacks: 'standard non-DLR,' 'standard DLR,' 'fast non-DLR,' and 'fast DLR.' Three raters qualitatively evaluated 'standard non-DLR' and 'fast DLR' for i) bulk motion (4-point scale), ii) nerve conspicuity of proximal and distal suprascapular and axillary nerves (5-point scale), and iii) nerve signal intensity, size, architecture, and presence of a mass (binary). ANOVA or Wilcoxon signed rank test compared differences. Gwet's agreement coefficient (AC2) assessed inter-rater agreement. RESULTS: Quantitative SNR and edge sharpness were superior for DLR versus non-DLR (SNR by + 4.57 to + 6.56 [p < 0.001] for 'standard' and + 4.26 to + 4.37 [p < 0.001] for 'fast;' sharpness by + 0.23 to + 0.52/pixel for 'standard' [p < 0.018] and + 0.21 to + 0.25/pixel for 'fast' [p < 0.003]) and similar between 'standard non-DLR' and 'fast DLR' (SNR: p = 0.436-1, sharpness: p = 0.067-1). Qualitatively, 'standard non-DLR' and 'fast DLR' had similar motion artifact, as well as nerve conspicuity, signal intensity, size and morphology, with high inter-rater agreement (AC2: 'standard' = 0.70-0.98, 'fast DLR' = 0.69-0.97). CONCLUSION: DLR applied to faster, 3D MRN acquisitions provides similar image quality to standard scans. A faster, DL-enabled protocol may replace currently optimized non-DL protocols.

The value of the cinematic volume rendering technique: magnetic resonance imaging in diagnosing tumors associated with the brachial plexus.

PURPOSE: To examine the diagnostic advantages and clinical application value of the cinematic volume rendering technique (cVRT) when evaluating the relationship between the brachial plexus, peripheral tumor lesions, and blood vessels. MATERIALS AND METHODS: Seventy-nine patients with brachial plexus tumors between November 2012 and July 2022 were enrolled in our study. All patients underwent T1WI, T2WI, three-dimensional short recovery time reversal recovery fast spin-echo imaging (3D-STIR-SPACE), and the T1WI enhancement sequence. In addition, cVRT was used to render and obtain a three-dimensional model that clearly showed the location and tissue structure of the brachial plexus nerves and the tumor in all directions. RESULTS: Seventy-one patients (mean age, 47.1 years; 33 males, 38 females) with tumors around the brachial plexus were included in the study. The brachial plexus nerve, surrounding tumor lesions, and vascular anatomy of all patients were well displayed with cVRT. The tumors of 37 patients manifested as unilateral or bilateral growths along the brachial plexus nerve and were fusiform, spherical, or multiple beaded; seven patients' tumors pushed against the brachial plexus nerve and were circular, lobular, or irregular; sixteen patients' tumors encircled the brachial plexus nerve and were spherical; and eleven patients' tumors infiltrated the brachial plexus nerve and had irregular morphology. The mass has a moderately uniform or uneven signal on T1WI and a high or mixed signal on T2WI. After enhancement, the signal was evenly or unevenly strengthened. CONCLUSIONS: cVRT clearly showed the origin of tumors associated with the brachial plexus and their relationship with the nerves and peripheral blood vessels, providing reliable information for clinical diagnosis and treatment.

[Thoracoscopic Resection of Schwannoma Using Intraoperative Neurophysiological Monitoring: Report of a Case].

A 28-year-old right-handed woman had been diagnosed with a tumor of 30 mm in a diameter at the right first intercostal space adjacent to brachial nerve plexus. It was incidentally detected by medical checkup examination five years ago. Because the tumor enlarged to 36 mm in five years without any symptoms, thoracoscopic tumor resection was planned for diagnosis. Intraoperative neurophysiological monitoring (IONM) was performed to prevent brachial plexus nerve injury. The tumor was totally removed via thoracoscopic approach without postoperative neurological deficit. Histopathological diagnosis was schwannoma. In order to reduce the risk of neural injury, IONM is useful in thoracoscopic removal of the peripheral nerve tumor.

Diagnostic performance of deep learning-based reconstruction algorithm in 3D MR neurography.

OBJECTIVE: The study aims to evaluate the diagnostic performance of deep learning-based reconstruction method (DLRecon) in 3D MR neurography for assessment of the brachial and lumbosacral plexus. MATERIALS AND METHODS: Thirty-five exams (18 brachial and 17 lumbosacral plexus) of 34 patients undergoing routine clinical MR neurography at 1.5 T were retrospectively included (mean age: 49 ± 12 years, 15 female). Coronal 3D T2-weighted short tau inversion recovery fast spin echo with variable flip angle sequences covering plexial nerves on both sides were obtained as part of the standard protocol. In addition to standard-of-care (SOC) reconstruction, k-space was reconstructed with a 3D DLRecon algorithm. Two blinded readers evaluated images for image quality and diagnostic confidence in assessing nerves, muscles, and pathology using a 4-point scale. Additionally, signal-to-noise ratio (SNR) and contrast-to-noise ratios (CNR) between nerve, muscle, and fat were measured. For comparison of visual scoring result non-parametric paired sample Wilcoxon signed-rank testing and for quantitative analysis paired sample Student's t-testing was performed. RESULTS: DLRecon scored significantly higher than SOC in all categories of image quality (p < 0.05) and diagnostic confidence (p < 0.05), including conspicuity of nerve branches and pathology. With regard to artifacts there was no significant difference between the reconstruction methods. Quantitatively, DLRecon achieved significantly higher CNR and SNR than SOC (p < 0.05). CONCLUSION: DLRecon enhanced overall image quality, leading to improved conspicuity of nerve branches and pathology, and allowing for increased diagnostic confidence in evaluation of the brachial and lumbosacral plexus.

Patient demographics, tumor characteristics, and outcomes following surgical treatment of benign and malignant brachial plexus tumors: a systematic review.

BACKGROUND: Various treatment options have been introduced for the management of primary tumors of the brachial plexus (BP), ranging from conservative therapy to wide local excision with/without postoperative chemoradiotherapy. However, no consensus exists regarding optimal treatment strategies based on collated and published data. OBJECTIVE: The aim of this study was to investigate the clinicopathological characteristics and outcome of patients with primary tumors of the BP who underwent surgical treatment. DATA SOURCES: A systematic search of the four main online databases, including Web of Science (WOS), PubMed, Scopus, and Google Scholar, was conducted. STUDY SELECTION: All related articles addressing the clinical outcome and role of surgical interventions for management of primary tumors of the BP. INTERVENTION: Optimal surgical and radiotherapeutic interventions for benign and malignant lesions based on the pathologic characteristics and location of primary BP tumors. RESULTS: A total of 687 patients (693 tumors) with a mean age of 41.7±8.7 years old were evaluated. In total, 629 (90.8%) tumors were benign, and 64 (9.2%) were malignant, with a mean tumor size of 5.4±3.1 cm. The location of the tumor was reported for 639 patients. For these tumors, 444 (69.5%) originated from the supraclavicular region, and 195 (30.5%) were infraclavicular. The trunks were the most common location for tumor involvement, followed by the roots, cords, and terminal branches. Gross total resection was achieved in 432 patients and subtotal resection (STR) was performed in 109 patients. With neurofibromas, STR still resulted in good outcomes. The outcomes following treatment of malignant peripheral nerve sheath tumors were poor regardless of the type of resection. In general, symptoms related to pain and sensory issues resolved rapidly postoperatively. However, the resolution of motor deficits was often incomplete. Local tumor recurrence occurred in 15 (2.2%), patients and distant metastasis was observed in only eight (1.2%) cases. The overall mortality was 21 (3.1%) patients among the study population. LIMITATIONS: The main limitation was the lack of level I and II evidence. CONCLUSIONS: The ideal management strategy for primary BP tumors is complete surgical resection. However, in some cases, particularly for neurofibromas, STR may be preferable to preserve maximal neurological function. The degree of surgical excision (total or subtotal) mainly depends on the pathological characteristics and primary location of the tumor.

Brachial Plexus Nerve Injuries and Disorders: MR Imaging-Ultrasound Correlation.

Multimodality imaging of the brachial plexus is essential to accurately localize the lesion and characterize the pathology and site of injury. A combination of computed tomography (CT), ultrasound, and MR imaging is useful along with clinical and nerve conduction studies. Ultrasound and MR imaging in combination are effective to accurately localize the pathology in most of the cases. Accurate reporting of the pathology with dedicated MR imaging protocols in conjunction with Doppler ultrasound and dynamic imaging provides practical and useful information to help the referring physicians and surgeons to optimize medical or surgical treatment regimens.

Differentiation of Peripheral Nerve Tumors in the Brachial Plexus.

Schwannomas are benign extracranial nerve sheath tumors that can rarely affect the brachial plexus. Due to the relative rarity of these tumors and the complexity of the anatomy of the neck and shoulder, these tumors are a challenging diagnosis for clinicians. We present a case report of a 51-year-old male with a brachial plexus schwannoma definitively treated with surgical resection. It is our hope that this case serves as a reminder to consider schwannomas in the differential diagnosis for infraclavicular tumors.

Preganglionic Injury of C8 Nerve Root Secondary to Shoulder Disloca tion: Diagnosis based on MRI Findings.

INTRODUCTION: Traumatic spinal root injury caused by shoulder dislocation may involve the brachial plexus or, in some cases, a single nerve. The degree of severity of the injury depends on many patient-specific factors as well as the mechanism of injury. It is essential to suspect this type of lesion by means of a thorough physical examination in order to have better patient outcomes. CASE PRESENTATION: We presented the subtle magnetic resonance imaging (MRI) findings in a 35-yearold male with left shoulder trauma and dislocation after falling off a bicycle. He complained of decreased muscle strength and sensitivity in the C8 dermatome. Atrophy of the hypothenar region and flexion deformity of the 4th and 5th digits were noted. Magnetic resonance imaging findings were consistent with a partial preganglionic C8 motor root lesion. We found T2 increased signal intensity and thinning of the intradural segment of the C8 motor nerve root and low signal in the sequence of a multi- echo gradient recalled echo (GRE). CONCLUSION: MRI is a noninvasive tool that allows a detailed anatomical characterization of the nerves. In brachial plexus injuries, the use of the GRE sequence is useful to identify the lesions, even if they are subtle; however, some lesions may go unnoticed. It is important to note that these patients require an interdisciplinary group to reach a correct diagnosis, which is vital to establish the appropriate treatment and follow-up.

[Diagnostic value of F wave changes in patients with Charcot-Marie-Tooth1A and chronic inflammatory demyelinating polyneuropathy].

OBJECTIVE: To analyze and compare the characteristics and causes of F wave changes in patients with Charcot-Marie-Tooth1A (CMT1A) and chronic inflammatory demyelinating polyneuropathy (CIDP). METHODS: Thirty patients with CMT1A and 30 patients with CIDP were enrolled in Peking University Third Hospital from January 2012 to December 2018. Their clinical data, electrophysiological data(nerve conduction velocity, F wave and H reflex) and neurological function scores were recorded. Some patients underwent magnetic resonance imaging of brachial plexus and lumbar plexus, and the results were analyzed and compared. RESULTS: The average motor conduction velocity (MCV) of median nerve was (21.10±10.60) m/s in CMT1A and (31.52±12.46) m/s in CIDP. There was a significant difference between the two groups (t=-6.75, P < 0.001). About 43.3% (13/30) of the patients with CMT1A did not elicit F wave in ulnar nerve, which was significantly higher than that of the patients with CIDP (4/30, 13.3%), χ2=6.65, P=0.010. Among the patients who could elicit F wave, the latency of F wave in CMT1A group was (52.40±17.56) ms and that in CIDP group was (42.20±12.73) ms. There was a significant difference between the two groups (t=2.96, P=0.006). The occurrence rate of F wave in CMT1A group was 34.6%±39%, and that in CIDP group was 70.7%±15.2%. There was a significant difference between the two groups (t=-5.13, P < 0.001). The MCV of median nerve in a patient with anti neurofascin 155 (NF155) was 23.22 m/s, the latency of F wave was 62.9-70.7 ms, and the occurrence rate was 85%-95%. The proportion of brachial plexus and lumbar plexus thickening in CMT1A was 83.3% (5/6) and 85.7% (6/7), respectively. The proportion of brachial plexus and lumbar plexus thickening in the CIDP patients was only 25.0% (1/4, 2/8). The nerve roots of brachial plexus and lumbar plexus were significantly thickened in a patient with anti NF155 antibody. CONCLUSION: The prolonged latency of F wave in patients with CMT1A reflects the homogenous changes in both proximal and distal peripheral nerves, which can be used as a method to differentiate the CIDP patients characterized by focal demyelinating pathology. Moreover, attention should be paid to differentiate it from the peripheral neuropathy caused by anti NF155 CIDP. Although F wave is often used as an indicator of proximal nerve injury, motor neuron excitability, anterior horn cells, and motor nerve myelin sheath lesions can affect its latency and occurrence rate. F wave abnormalities need to be comprehensively analyzed in combination with the etiology, other electrophysiological results, and MRI imaging.

Brachial Plexus Magnetic Resonance Neurography: Technical Challenges and Solutions.

ABSTRACT: Magnetic resonance neurography of the brachial plexus (BP) is challenging owing to its complex anatomy and technical obstacles around this anatomic region. Magnetic resonance techniques to improve image quality center around increasing nerve-to-background contrast ratio and mitigating imaging artifacts. General considerations include unilateral imaging of the BP at 3.0 T, appropriate selection and placement of surface coils, and optimization of pulse sequences. Technical considerations to improve nerve conspicuity include fat, vascular, and respiratory artifact suppression techniques; metal artifact reduction techniques; and 3-dimensional sequences. Specific optimization of these techniques for BP magnetic resonance neurography greatly improves image quality and diagnostic confidence to help guide nonoperative and operative management.

Isolated Primary Neurolymphomatosis in the Right Brachial Plexus Proven by Partial Nerve Biopsy.

INTRODUCTION: Isolated primary neurolymphomatosis is a rare manifestation of lymphoma, which is challenging to diagnose as there is only involvement of the nervous system, and nerve biopsy is not frequently pursued due to the high risk of irreversible complications. CASE REPORT: We present a case of isolated primary neurolymphomatosis of diffuse large B-cell lymphoma restricted to only the right brachial plexus and right axillary nerve. The clinical course has been indolent for several years. The initial examination, including MRI and the cerebrospinal fluid study, did not yield any evidence of malignancy. Eventually, due to the patient's symptom progression and the follow-up imaging findings, we conducted a partial nerve biopsy of the brachial plexus to confirm the malignancy. His neurological symptoms did not further deteriorate post-biopsy. CONCLUSION: Isolated primary neurolymphomatosis with an indolent course is rare and challenging to diagnose. Serial MRI and fluorodeoxyglucose-positron emission tomography reveal clues for tumor involvement. Partial nerve biopsy or targeted fascicular nerve biopsy could be an alternative for achieving a pathologic diagnosis.

Diagnostic value of F wave changes in patients with Charcot-Marie-Tooth1A and chronic inflammatory demyelinating polyneuropathy / 北京大学学报(医学版)

OBJECTIVE@#To analyze and compare the characteristics and causes of F wave changes in patients with Charcot-Marie-Tooth1A (CMT1A) and chronic inflammatory demyelinating polyneuropathy (CIDP).@*METHODS@#Thirty patients with CMT1A and 30 patients with CIDP were enrolled in Peking University Third Hospital from January 2012 to December 2018. Their clinical data, electrophysiological data(nerve conduction velocity, F wave and H reflex) and neurological function scores were recorded. Some patients underwent magnetic resonance imaging of brachial plexus and lumbar plexus, and the results were analyzed and compared.@*RESULTS@#The average motor conduction velocity (MCV) of median nerve was (21.10±10.60) m/s in CMT1A and (31.52±12.46) m/s in CIDP. There was a significant difference between the two groups (t=-6.75, P < 0.001). About 43.3% (13/30) of the patients with CMT1A did not elicit F wave in ulnar nerve, which was significantly higher than that of the patients with CIDP (4/30, 13.3%), χ2=6.65, P=0.010. Among the patients who could elicit F wave, the latency of F wave in CMT1A group was (52.40±17.56) ms and that in CIDP group was (42.20±12.73) ms. There was a significant difference between the two groups (t=2.96, P=0.006). The occurrence rate of F wave in CMT1A group was 34.6%±39%, and that in CIDP group was 70.7%±15.2%. There was a significant difference between the two groups (t=-5.13, P < 0.001). The MCV of median nerve in a patient with anti neurofascin 155 (NF155) was 23.22 m/s, the latency of F wave was 62.9-70.7 ms, and the occurrence rate was 85%-95%. The proportion of brachial plexus and lumbar plexus thickening in CMT1A was 83.3% (5/6) and 85.7% (6/7), respectively. The proportion of brachial plexus and lumbar plexus thickening in the CIDP patients was only 25.0% (1/4, 2/8). The nerve roots of brachial plexus and lumbar plexus were significantly thickened in a patient with anti NF155 antibody.@*CONCLUSION@#The prolonged latency of F wave in patients with CMT1A reflects the homogenous changes in both proximal and distal peripheral nerves, which can be used as a method to differentiate the CIDP patients characterized by focal demyelinating pathology. Moreover, attention should be paid to differentiate it from the peripheral neuropathy caused by anti NF155 CIDP. Although F wave is often used as an indicator of proximal nerve injury, motor neuron excitability, anterior horn cells, and motor nerve myelin sheath lesions can affect its latency and occurrence rate. F wave abnormalities need to be comprehensively analyzed in combination with the etiology, other electrophysiological results, and MRI imaging.

Natural History of Brachial Plexus, Peripheral Nerve, and Spinal Schwannomas.

BACKGROUND: Management of sporadic schwannomas is often dictated by a patient's clinical presentation and the tumor's behavior. For patients who are managed nonsurgically, there are little data available about the expected natural history. OBJECTIVE: To evaluate the natural history and growth patterns of extracranial schwannomas including tumors of the distal peripheral nerves, spine, and brachial plexus. METHODS: A retrospective review was performed to identify patients with nonsyndromic extracranial schwannomas at a single tertiary care institution diagnosed between 2002 and 2019. Patient data and tumor characteristics including volume were recorded. RESULTS: Two hundred twenty-seven patients were identified (mean age 51 years, 42% male, average of 27.8-month follow-up). Tumor location was distal peripheral nerve in 82, brachial plexus in 36, and paraspinal in 109. At the time of diagnosis, peripheral lesions were significantly larger than spinal (59 m 3 vs 13 cm 3 ) and brachial plexus lesions (15 cm 3 ). Distinct growth patterns were seen with both distal peripheral nerve and spinal lesions; 34/82 peripheral nerve lesions had fast growth (ß = 0.176%/day), and 48 had slow growth (ß = 0.021%/day; P < .01). Spinal schwannomas similarly had 30 fast-growing (ß = 0.229%/day), 16 moderate-growing (ß = 0.071%/day), and 63 slow-growing (ß = 0.022%/day; P = .03) subtypes. The brachial plexus had relatively homogeneous growth patterns (ß = 0.065%/day). Females had 2.9 times greater odds of having the fast-growing subtype. CONCLUSION: Distinct growth patterns were seen in extracranial sporadic schwannomas based on tumor location and patient demographics. Fast (>80% volume change per year) vs slow (5%-10% per year) tumor growth can often be ascertained within 2 follow-up images. Awareness of these patterns might have implications for patient counseling and therapeutic decision-making.

An Uncommon, Extensive Involvement of Hydatid Cyst-Cervical Spine to Brachial Plexus.

Introduction: Hydatid cyst usually involves liver and lung. But it has been reported in uncommon locations like the spine and brain. There are few reports of cervical spine to brachial plexus. This report is about such extensively involved hydatid cyst management. Case Report: A 32-year-old male had complaints of neck pain, left-hand weakness, and atrophy. MRI of cervical spine and thorax revealed a multicystic lesion involving the cervical spine, vertebrae, brachial plexus, and lung apex. The lesion was removed in two stages. Discussion: Due to scarcity of literature, dense adhesions with dura and surroundings, risk of rupture, anaphylactic shock, and its management require proper planning. Excision of cervical, followed by plexus lesion, might help. Long-term use of albendazole prevents recurrence as suggested by other reports. Conclusion: Extensive spinal hydatid cyst is exceptionally challenging. These behave like malignant lesions. To get the best results, surgical planning is as essential as medical management.

CLINICAL AND NEUROPHYSIOLOGICAL PARALLELS OF THE BRACHIAL PLEXOPATHY IN THE STRUCTURE OF NEUROGENIC THORACIC OUTLET SYNDROME.

OBJECTIVE: The aim: Was assessment of the neurophysiological data and features of clinical picture in patients with neurogenic thoracic outlet syndrome (TOS). PATIENTS AND METHODS: Materials and methods: 103 patients with upper extremity pain and/or paresthesia or hypotrophy, or a combination of these symptoms were examined. The examination algorithm included: cervical spine radiography, cervical spine and brachial plexuses magnetic resonance imaging (MRI), upper extremity soft tissues and vessels ultrasonic examination, stimulation electroneuromiography with F-waves registration. RESULTS: Results: Neurogenic TOS was diagnosed in 29 patients. A significant relationship between the following complaints and neurophysiological parameters was observed: pain, numbness during physical activity and decreased medial anrebrachial cutaneous nerve response amplitude by ≥25% compared to the contralateral side; hypothenar hypotrophy and decrease of ulnar nerve motor/sensory response amplitude; the 4-5th fingers hypoesthesia and decrease of ulnar nerve sensory response amplitude. CONCLUSION: Conclusions: Medial antebrachial cutaneous nerve amplitudes asymmetry indices of ≥25% or lack of response may be considered to be a marker of true neurogenic TOS.

Axial T2-DRIVE MRI myelography is highly accurate in diagnosing preganglionic traumatic brachial plexus injuries: why pseudomeningoceles should not be used as a primary diagnostic sign.

AIM: To evaluate the accuracy of brachial plexus magnetic resonance imaging (MRI) utilising the three-dimensional (3D)-T2-turbo spin echo (TSE) with 90° flip-back pulse ("DRIVE") myelography in detecting nerve root avulsions in patients with traumatic brachial plexus injuries. MATERIALS AND METHODS: A prospective study of 24 patients planned for brachial plexus reconstructive surgery following trauma from April 2019 to October 2021. Preoperative 1.5 T MRI of the brachial plexus was performed utilising axial T2-DRIVE, looking for signs of avulsions (absent dural rootlets, pauci-rootlet appearance and thickened rootlets; the presence of pseudomeningoceles was noted only as an ancillary sign). Comparison against the reference standard of extra-dural brachial plexus exploration was performed. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy were calculated. RESULTS: Eighteen patients had at least one root avulsion at surgery, five showed isolated post-ganglionic injuries, and one had normal brachial plexus exploration. Thirty-nine avulsed roots were found at surgery (out of 108 explored in 24 patients). Preoperative MRI identified the specific avulsed roots accurately in each patient. Two false-positive diagnoses of C5 and C6 avulsions were made in one patient. On MRI, absence of the rootlets was seen in 73.2% (n=30) of avulsions, pauci-rootlet appearance in 24.4% (n=10) and thickening of the rootlets in 2.4% (n=1). Pseudomeningoceles were found only in 68.3% (n=28) of avulsions. The overall sensitivity, specificity, PPV, NPV, and accuracy of MRI were 100%, 97.1%, 95.1%, 100% and 98.1%, respectively. CONCLUSION: 3D-T2-DRIVE is highly accurate in evaluating pre-ganglionic traumatic brachial plexus injuries. Pseudomeningoceles can be considered an ancillary feature of avulsion given the clarity of rootlet visualisation by this sequence.

Stereotactic Body Radiation Therapy for Apical Lung Tumors: Dosimetric Analysis of the Brachial Plexus and Preliminary Clinical Outcomes.

PURPOSE: Dosimetric constraints of the brachial plexus have not yet been well-established for patients undergoing stereotactic body radiation therapy (SBRT). This study evaluated long-term experience with the treatment of early-stage apical lung tumors with SBRT and reports on dosimetric correlates of outcome. METHODS AND MATERIALS: Between 2009 and 2018, a total of 78 consecutive patients with 81 apical lung tumors underwent SBRT for T1-3N0 non-small cell lung cancer. Apical tumors were those with tumor epicenter superior to the aortic arch. The brachial plexus (BP) was anatomically contoured according to the Radiation Therapy Oncology Group atlas. Patient medical records were reviewed retrospectively to determine incidence of brachial plexus injury (BPI) and a normal tissue complication probability model was applied to the dosimetric data. RESULTS: Five patients (6.4%) reported neuropathic symptoms consistent with BPI and occurred a median 11.9 months after treatment (range, 5.2-28.1 months). Most common dose and fractionation in those developing BPI were 50 Gy in 5 fractions (4 patients). Symptoms consisted of pain in 2 patients (40.0%), numbness in the hand or axilla in 4 patients (80.0%), and ipsilateral hand weakness in 1 patient (20.0%). In the overall cohort the median BP Dmax (EQD23 Gy) was 5.13 Gy (range, 0.18-217.2 Gy) and in patients with BPI the median BP Dmax (EQD23 Gy) was 32.14 Gy (range, 13.4-99.9 Gy). The normal tissue complication probability model gave good fit with an area under the curve of 0.75 (odds ratio, 7.3; 95% confidence interval, 0.8-68.3) for BP Dmax (EQD23 Gy) threshold of 20 Gy. CONCLUSIONS: Significant variation exists in the dose delivered to the brachial plexus for patients treated by SBRT for apical lung tumors. The incidence of neuropathic symptoms in the post-SBRT setting was appreciable and prospective clinical correlation with dosimetric information should be used to develop evidence-based dose constraints.

Diagnostic performance of diffusion-weighted MR neurography as an adjunct to conventional MRI for the assessment of brachial plexus pathology.

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/mm2) 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%).

Nerve Hypertrophy and Altered Diffusion in Anti-Myelin-Associated Glycoprotein Neuropathy Detected by Brachial Plexus Magnetic Resonance Neurography.

INTRODUCTION: This study assessed the morphological changes and diffusion tensor imaging (DTI)-derived parameters of the brachial plexus using magnetic resonance neurography (MRN) in patients with anti-myelin-associated glycoprotein (anti-MAG) neuropathy. METHODS: Eight patients with anti-MAG neuropathy underwent MRN of the brachial plexus with 3-dimensional (3D) short tau inversion recovery (STIR) and DTI sequences. Two neuroradiologists and a neurologist qualitatively assessed nerve hypertrophy on 3D STIR MRN. The cross-sectional area (CSA) of the nerve roots was measured. Quantitative analyses of fractional anisotropy (FA) and axial, radial, and mean diffusivity (AD, RD, and MD) were obtained after postprocessing on DTI and manual segmentation. RESULTS: There was nerve hypertrophy in 37.5% of the patients with anti-MAG neuropathy. All patients with anti-MAG neuropathy with nerve hypertrophy were refractory to rituximab therapy. The CSA of the nerve roots was inversely correlated with FA and positively correlated with MD and RD. FA decreased in the nerve roots and inversely correlated with disease duration. CONCLUSIONS: Nerve hypertrophy appears in the proximal portion of peripheral nerves, such as the brachial plexus, in patients with anti-MAG neuropathy. Altered diffusion in the nerve roots might be associated with the loss of myelin integrity due to the demyelination process in anti-MAG neuropathy.

Imaging of non-specific complaints of the arm, neck, and/or shoulder (CANS): role of the scalene muscles and piercing variants in neurogenic thoracic outlet syndrome.

Complaints of the arm, neck and/or shoulder (CANS) are common in the general population (40%) and workers (30%) and have significant economic impact. Twenty-three conditions have been designated as specific CANS. Cases where no cause is identified are reported as non-specific CANS; these cases make up the majority of CANS. Non-specific CANS presentations overlap with clinical entities including cervicobrachial and scalene myofascial syndromes that are associated with neurogenic thoracic outlet syndrome (NTOS). The scalene muscles have been identified as the commonest site of NTOS, although this has been reported to be functional and in conjunction with cervicothoracic junction variants that compromise the brachial plexus lower trunk. Anatomical variants in relation to both the scalene muscles and brachial plexus are not widely recognised in the clinical and imaging literature; however, pass-through and pass-over (or "piercing") variants of the brachial plexus upper trunk and scalene muscles have been well described in the anatomical and anaesthetic literature. In this review, we demonstrate the presence and describe the imaging of scalene muscle pathology and variant muscle-brachial plexus anatomy affecting the upper trunk that are underdiagnosed causes of non-specific CANS presentations and NTOS.