MR imaging of brachial plexus

Follow-up imaging of anal cancer after treatment

Anal cancer treatment response assessment can be challenging with both magnetic resonance imaging (MRI) and clinical evaluation considered essential. MRI, in particular, has shown to be useful for the assessment of treatment response, the detection of recurrent disease in follow up and surveillance, and the evaluation of possible post-treatment complications as well as complications from the tumor itself. In this review, we focus on the role of imaging, mainly MRI, in anal cancer treatment response assessment. We also describe the treatment complications that can occur, and the imaging findings associated with those complications.

Diagnostic Accuracy of Magnetic Resonance Imaging With 3-Dimensional T2-SPACE Techniques for Preganglionic Injury of the Brachial Plexus

PURPOSE

An accurate diagnosis of the site and severity of a brachial plexus injury is imperative for selecting the appropriate management. Conventional magnetic resonance imaging (MRI) does not allow for the precise interpretation of preganglionic injuries (pre-GIs), especially intravertebral canal injuries. We developed 4 MRI sequences of conventional 1.5-tesla 3-dimensional T2-weighted turbo spin echo sampling perfection with the application of optimized contrasts using different flip angles evolution (T2-SPACE) images to clearly visualize each component of the brachial plexus. The purpose of this study was to introduce basic normal and pathologic findings of our current MRI approach, focusing on its diagnostic accuracy for pre-GIs.

METHODS

We initially examined 119 patients with brachial plexus injuries who underwent surgical exploration by MRI using 4 sequences of the 1.5-tesla 3-dimensional T2-SPACE technique. We obtained coronal, transverse, coronal oblique, and coronal cuts of T2 short time inversion recovery. The images of 595 roots were interpreted by multiple-image synchronizing techniques of the 4 views to precisely interpret the presence of spinal cord edema, numbers of anterior and posterior rootlets, sites of ganglions, meningeal cysts, and the "black line sign" (displaced ruptured dura or bundles of ruptured rootlets). We assessed the accuracy, sensitivity, and specificity of these abnormal findings with regard to diagnosing pre-GIs by comparing surgical exploration.

RESULTS

The absence or decreased numbers of anterior and posterior rootlets and displacement of ganglions were definitive evidence of pre-GIs and the other findings, like spinal cord edema, meningeal cysts, and black line signs, were predictive signs.

CONCLUSIONS

The synchronizing techniques of the four 1.5-tesla 3-dimensional T2-SPACE images provided high diagnostic accuracy of pre-GIs.

TYPE OF STUDY/LEVEL OF EVIDENCE

Diagnostic II.

Diagnostic Function of 3-Tesla Magnetic Resonance Imaging for the Assessment of Brachial Plexus Injury

Background:

This study aimed to evaluate the diagnostic function of 3-Tesla (T) magnetic resonance imaging (MRI) during the assessment of brachial plexus injury (BPI), in comparison with intraoperative findings.

Methods:

A retrospective study was performed on 60 patients (47 men and 13 women), who had clinical manifestations of BPI, underwent 3T MRI of the brachial plexus, and were surgically treated at the Viet Duc and Vinmec Times City hospitals, in Hanoi, Vietnam, from March 2016 to December 2019. Preganglionic and postganglionic lesion features were identified on MRI. The diagnostic function of MRI features for the determination of BPI was evaluated and correlated with intraoperative findings.

Results:

The root avulsion and pseudomeningocele preganglionic injuries were observed in 57% and 43% of MRIs, respectively, and were commonly observed at the C7 and C8 roots. Nerve disruption and never edema were observed in 47.56% and 33.53% of MRIs, respectively, and were commonly observed at the C5 and C6 roots. The sensitivity, specificity, accuracy, positive prognostic value, and negative prognostic value of 3T MRI were 64.12%, 92.90%, 80.33%, 87.50%, and 76.96%, respectively, for the diagnosis of total avulsion, and 68.52%, 83.33%, 80.67%, 47.44%, and 92.34%, respectively, for the diagnosis of nerve disruption.

Conclusion:

MRI offers valuable details regarding the location, morphology, and severity of both preganglionic and postganglionic injuries during the preoperative diagnosis of BPI. However, this modality played a moderate diagnostic role. Therefore, 3T MRI should be used as a supplemental evaluation, coupled with clinical tests and electromyography, to determine the most appropriate treatment strategies for BPI patients.

Volumetric Modulated Arc (Radio) Therapy in Pets Treatment: The "La Cittadina Fondazione" Experience

Volumetric Modulated Arc Therapy (VMAT) is a modern technique, widely used in human radiotherapy, which allows a high dose to be delivered to tumor volumes and low doses to the surrounding organs at risk (OAR). Veterinary clinics takes advantage of this feature due to the small target volumes and distances between the target and the OAR. Sparing the OAR permits dose escalation, and hypofractionation regimens reduce the number of treatment sessions with a simpler manageability in the veterinary field. Multimodal volumes definition is mandatory for the small volumes involved and a positioning device precisely reproducible with a setup confirmation is needed before each session for avoiding missing the target. Additionally, the elaborate treatment plan must pursue hard constraints and objectives, and its feasibility must be evaluated with a per patient quality control. The aim of this work is to report results with regard to brain meningiomas and gliomas, trigeminal nerve tumors, brachial plexus tumors, adrenal tumors with vascular invasion and rabbit thymomas, in comparison with literature to determine if VMAT is a safe and viable alternative to surgery or chemotherapy alone, or as an adjuvant therapy in pets.

Sciatic neuropathy: findings on magnetic resonance neurography

Injuries of the sciatic nerve are common causes of pain and limitation in the lower limbs. Due to its particular anatomy and its long course, the sciatic nerve is often involved in diseases of the pelvis or leg. In recent years, magnetic resonance neurography has become established as an important tool for the study of peripheral nerves and can be widely applied to the study of the sciatic nerve. Therefore, detailed knowledge of its anatomy and of the most prevalent diseases affecting it is essential to maximizing the accuracy of diagnostic imaging.

Frameless stereotactic volumetric modulated arc radiotherapy of brachial plexus tumours in dogs: 10 cases

OBJECTIVE

Treatment of canine peripheral nerve sheath tumours (PNSTs) is challenging and prognosis after surgical resection is considered poor. The aim of this study was to evaluate the feasibility and effectiveness of stereotactic radiotherapy (RT) of these tumours.

METHODS

10 dogs with clinical symptoms and MRI findings consistent with PNSTs of the brachial plexus, branches and nerve roots were treated with linear accelerator-based volumetric-modulated arc radiotherapy (VMAT) with a dose of 35 Gy/5 fractions. Clinical and MRI follow-up examinations were planned and radiotoxicity and survival times were investigated.

RESULTS

Tumours involved the plexus and proximal nerves in three dogs, the plexus, proximal nerves and nerve roots in five dogs and the nerve roots and proximal nerves in two dogs. Partial response and partial or complete reductions of neurological deficits were observed in all the treated dogs. Local recurrence was observed in 9/10 of treated dogs. No symptom directly referable to radiotoxicity was observed. Mean overall survival of 371 ± 30 days [95% confidence interval (CI) of (315-427)] and mean progression-free survival of 240 ± 30 days (95% CI of 188-291) from this work are comparable with surgical literature data regarding the plexus and proximal nerve localization, but are superior in comparison with nerve root localization.

CONCLUSION

VMAT can be a safe and viable alternative to surgery in cases of canine brachial plexus PNSTs involving the proximal nerves and nerve roots. Advances in knowledge: To our knowledge, this is the first prospective observational clinical study regarding VMAT stereotactic RT treatment for canine brachial plexus PNSTs and suggests that VMAT may achieve at least similar clinical outcome than surgery in a safer way.

Magnetic resonance imaging in brachial plexus injury

Brachial plexus injury represents the most severe nerve injury of the extremities. While obstetric brachial plexus injury has showed a reduction in the number of cases due to the improvements in obstetric care, brachial plexus injury in the adult is an increasingly common clinical problem. The therapeutic measures depend on the pathologic condition and the location of the injury: Preganglionic avulsions are usually not amenable to surgical repair; function of some denervated muscles can be restored with nerve transfers from intercostals or accessory nerves and contralateral C7 transfer. Postganglionic avulsions are repaired with excision of the damaged segment and nerve autograft between nerve ends or followed up conservatively. Magnetic resonance imaging is the modality of choice for depicting the anatomy and pathology of the brachial plexus: It demonstrates the location of the nerve damage (crucial for optimal treatment planning), depicts the nerve continuity (with or without neuroma formation), or may show a completely disrupted/avulsed nerve, thereby aiding in nerve-injury grading for preoperative planning. Computed tomography myelography has the advantage of a higher spatial resolution in demonstration of nerve roots compared with MR myelography; however, it is invasive and shows some difficulties in the depiction of some pseudomeningoceles with little or no communication with the dural sac.

Brachial plexopathy

Brachial plexus injury can occur as a result of trauma, inflammation or malignancies, and associated complications. The current topic is concerned with various forms of brachial plexopathy, its clinical features, pathophysiology, imaging findings, and management. Idiopathic brachial neuritis (IBN), often preceded with antecedent events such as infection, commonly present with abruptonset painful asymmetric upper limb weakness with associated wasting around the shoulder girdle and arm muscles. Idiopathic hypertrophic brachial neuritis, a rare condition, is usually painless to begin with, unlike IBN. Hereditary neuralgic amyotrophy is an autosomal-dominant disorder characterized by repeated episodes of paralysis and sensory disturbances in an affected limb, which is preceded by severe pain. While the frequency of the episodes tends to decrease with age, affected individuals suffer from residual deficits. Neurogenic thoracic outlet syndrome affects the lower trunk of the brachial plexus. It is diagnosed on the basis of electrophysiology and is amenable to surgical intervention. Cancer-related brachial plexopathy may occur secondary to metastatic infiltration or radiation therapy. Traumatic brachial plexus injury is commonly encountered in neurology, orthopedic, and plastic surgery set-ups. Trauma may be a direct blow or traction or stretch injury. The prognosis depends on the extent and site of injury as well as the surgical expertise.

Diagnostic performance of ultrasound in patients with suspected brachial plexus lesions in adults: a multicenter retrospective study with MRI, surgical findings and clinical follow-up as reference standard

PURPOSE

To evaluate brachial plexus ultrasound (US) performance in a large multicenter study.

MATERIALS AND METHODS

The research was approved by the Institutional Review Boards, and all patients gave written informed consent. A multicenter retrospective trial including three centers was performed between March, 2006 and April, 2011. A total of 204 patients who received a brachial plexus ultrasound requested by the referring physician were enrolled: magnetic resonance imaging, surgical findings and clinical follow-up of at least 12 months were used as the reference standard. Sensitivity, specificity with 95 % confidence intervals (CIs), positive predictive value (PPV), pre-test-probability (the prevalence), negative predictive value (NPV), pre- and post- test odds (OR), likelihood ratio for positive results (LH+), likelihood ratio for negative results (LH-), accuracy and post-test probability (post-P) were reported on a per-patient basis.

RESULTS

The overall sensitivity and specificity with 95 % CIs were: 0.76 (0.75-0.97); 0.96 (0.77-0.89). Overall PPV, pre-test probability, NPV, pre-OR, post-OR, LH+, LH-, Accuracy and post-P were: 0.93/0.43/0.84/0.75/0.75/13.4/17.6/0.25/0.88/0.93, respectively.

CONCLUSIONS

The specificity of brachial plexus US in patients suspected of having a brachial plexus lesion is very high.

Magnetic resonance imaging in bilateral brachial neuritis with pure sensory involvement

Brachial neuritis is characterized by shoulder and arm pain followed by weakness and atrophy of affected muscles and sensory loss in the arm. Isolated sensory involvement of the brachial plexus is very rare. Diagnosis of brachial neuritis is usually based on clinical history and examination, with the confirmation by electrodiagnostic tests. A 72-year-old woman presented with numbness and tingling in the bilateral upper extremities. While nerve conduction examination revealed only sensory abnormalities of the bilateral upper extremities, magnetic resonance imaging (MRI) showed thickening and hyperintensity of the bilateral brachial plexus. We report a case of bilateral brachial neuritis with clinical and electrophysiological pure sensory involvement diagnosed using brachial plexus MRI. Although electrophysiological examination is thought to be the best diagnostic technique in the diagnosis of brachial neuritis, its findings sometimes indicate a distal lesion, while the involvement of the whole brachial plexus can be seen in MRI.

Malignant brachial plexopathy: A pictorial essay of MRI findings

For imaging, the brachial plexus is a technically and anatomically challenging region of the peripheral nervous system. MRI has a central role in the identification and accurate characterization of malignant lesions arising here, as also in defining their extent and the status of the adjacent structures. The purpose of this pictorial essay is to describe the MRI features of primary and secondary malignant brachial plexopathies and radiation-induced brachial nerve damage.

MR imaging of the brachial plexus: comparison between 1.5-T and 3-T MR imaging: preliminary experience

OBJECTIVE

To compare 1.5-T and 3-T magnetic resonance (MR) imaging of the brachial plexus.

MATERIALS AND METHODS

Institutional review board approval and informed consent were obtained from 30 healthy volunteers and 30 consecutive patients with brachial plexus disturbances. MR was prospectively performed with comparable sequence parameters and coils with a 1.5-T and a 3-T system. Imaging protocols at both field strengths included T1-weighted turbo spin-echo (tSE) sequences and T2-weighed turbo spin-echo (tSE) sequences with fat saturation. The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) between muscle and nerve were calculated for both field strengths. The visibility of brachial plexus nerve at various anatomic levels (roots, interscalene area, costoclavicular space, and axillary level) was analyzed with a four-point grading scale by two radiologists. MR imaging diagnoses and pathological findings were also compared qualitatively.

RESULTS

SNR and CNRs were significantly higher on 3-T MR images than on 1.5-T MR images (Friedman test) for all sequences. Nerve visibility was significantly better on 3-T MR images than on 1.5-T MR images (paired sign test). Pathological findings (n = 30/30) were seen equally well with both field strengths. MR imaging diagnoses did not differ for the 1.5- and 3-T protocols.

CONCLUSIONS

High-quality MR images of the brachial plexus can be obtained with 3-T MR imaging by using sequences similar to those used at 1.5-T MR imaging. In patients and healthy volunteers, the visibility of nerve trunks and cords at 3-T MR imaging appears to be superior to that at 1.5-T MR imaging.

Brachial plexus assessment with three-dimensional isotropic resolution fast spin echo MRI: comparison with conventional MRI at 3.0 T

OBJECTIVE

The purpose of our study was to determine whether a three-dimensional (3D) isotropic resolution fast spin echo sequence (FSE-cube) has similar image quality and diagnostic performance to a routine MRI protocol for brachial plexus evaluation in volunteers and symptomatic patients at 3.0 T. Institutional review board approval and written informed consent were guaranteed.

METHODS

In this prospective study FSE-cube was added to the standard brachial plexus examination protocol in eight patients (mean age, 50.2 years) with brachial plexus pathologies and in six volunteers (mean age, 54 years). Nerve visibility, tissue contrast, edge sharpness, image blurring, motion artefact and acquisition time were calculated for FSE-cube sequences and for the standard protocol on a standardised five-point scale. The visibility of brachial plexus nerve and surrounding tissues at four levels (roots, interscalene area, costoclavicular space and axillary level) was assessed.

RESULTS

Image quality and nerve visibility did not significantly differ between FSE-cube and the standard protocol (p>0.05). Acquisition time was statistically and clinically significantly shorter with FSE-cube (p<0.05). Pathological findings were seen equally well with FSE-cube and the standard protocol.

CONCLUSION

3D FSE-cube provided similar image quality in a shorter acquisition time and enabled excellent visualisation of brachial plexus anatomy and pathology in any orientation, regardless of the original scanning plane.

Obstetric brachial plexus lesions: CT myelography

PURPOSE

To evaluate the value of computed tomographic (CT) myelography in the detection of root damage and differentiation of root avulsions from neurotmesis in a large cohort of patients with an obstetric brachial plexus lesion (OBPL).

MATERIALS AND METHODS

Institutional review board approval was obtained. Informed consent was waived by the medical ethics committee. One hundred eighteen patients with OBPL born in the cephalic position and six patients born in the breech position were selected for surgery by two neurosurgeons in a multidisciplinary team. Functional loss of the C5 through T1 innervated muscles was noted. All patients underwent preoperative CT myelography at an average age of 19 weeks. CT myelographic examination results were reviewed by two radiologists, who were blinded to the clinical findings, for the presence of root avulsions and pseudocysts. Interobserver agreement was assessed by calculating κ values.

RESULTS

CT myelographic results showed root avulsions in at least one level in 66 (56%) of 118 patients born in the cephalic position and in six (100%) of six patients born in the breech position. Levels C7 and C8 showed the most root avulsions, even if not expected from clinical examination results. A large number of root avulsions showed pseudocysts (73 [68%] of 107 levels in patients born in the cephalic position and 11 [73%] of 15 levels in patients born in the breech position).

CONCLUSION

CT myelographic results showed root avulsions in more than half of patients with OBPL. Root avulsions were even detected at levels that were not expected at clinical examination. Because root avulsions require specific reconstructive techniques, CT myelography is recommended for every preoperative patient with OBPL.

A valuable non-invasive diagnostic investigation for paediatric idiopathic brachial neuritis

Idiopathic brachial neuritis (idiopathic neuralgic amyotrophy) in children is a well-recognized but rare condition. Although the precise aetiology is unknown, its usual occurrence after an infection suggests an immunological process. There is no specific test for brachial neuritis, and the diagnosis is one of exclusion with supportive evidence from nerve conduction studies, electromyography (EMG), and, in adults, changes in affected muscles on magnetic resonance imaging. Young children are often unable to tolerate EMG.

Brachial plexopathy after chemoradiotherapy for head and neck squamous cell carcinoma

PURPOSE

To evaluate late brachial plexopathy after primary chemoradiotherapy for locally advanced head and neck squamous cell carcinoma.

PATIENTS AND METHODS

Consecutive 43 disease-free patients were evaluated by a specifically developed 26-item questionnaire. Retrospectively, the brachial plexus was delineated and the dose-volume histograms were calculated.

RESULTS

After a median follow-up of 24 months, no radiation-induced brachial plexopathy was reported in these 43 patients.

CONCLUSION

No radiation-induced brachial plexopathy was seen in the patient group, although 72.1% of the brachial plexuses received doses > 60 Gy. These findings should prompt further prospective studies and also stress the importance of trying to keep the doses to the brachial plexus as low as possible while covering the target volumes well.

MRI of the brachial plexus: a pictorial review

Magnetic resonance imaging (MRI) of the brachial plexus is the imaging modality of first choice for depicting anatomy and pathology of the brachial plexus. The anatomy of the roots, trunks, divisions and cords is very well depicted due to the inherent contrast differences between the nerves and the surrounding fat. In this pictorial review the technique and the anatomy will be discussed. The following pathology will be addressed: neurogenic tumors of the brachial plexus and sympathetic chain, superior sulcus tumors, other tumors in the vicinity of the brachial plexus, the differentiation between radiation and metastatic plexopathy, trauma, neurogenic thoracic outlet syndrome and immune-mediated neuropathies.

MR imaging findings in brachial plexopathy with thoracic outlet syndrome

The BPL is a part of the peripheral nervous system. Many disease processes affect the BPL. In this article, on the basis of 60 patients, we reviewed MR imaging findings of subjects with brachial plexopathy. Different varieties of BPL lesions are discussed.

Brachial plexopathy following herpes zoster infection: two cases with MRI findings

There are few reports of brachial plexopathy following the onset of a herpes zoster skin rash. Moreover, the MRI findings of zoster-induced brachial plexopathy have rarely been described. In the present study, we describe two cases of zoster brachial plexopathy and their MRI findings. MRI of the brachial plexus demonstrated T2 hyperintensity and contrast enhancement in the part of the brachial plexus that was compatible with both the clinical symptoms and the electrophysiological findings. Especially, MR imaging reflected the functional impairments more accurately than electrophysiological studies in the acute phase, during which MRI showed more extensive inflammatory involvement of the brachial plexus. MRI findings in the present cases suggest that, in addition to electrophysiological studies, MRI of the brachial plexus could provide valuable information for evaluating the location and extent of lesions and for understanding the pathophysiological mechanisms of zoster brachial plexopathy.

Acute painless shoulder weakness during high-intensity athletic training

BACKGROUND

High-intensity repetitive athletic activities may predispose the brachial plexus to repetitive stretch, compression, and subsequent injury, although painless shoulder weakness is a rare event.

PURPOSE

The physical examination and electrodiagnostic findings in a series of United States Navy special warfare trainees who presented with acute painless shoulder weakness are presented, along with subsequent treatment and return-to-duty timeline.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

From August 2005 to August 2006, a total of 11 of 212 (5%) Navy Basic Underwater Demolition School trainees were identified with acute onset (<3 weeks) painless shoulder weakness without any prior shoulder injury. In all shoulders, symptoms began during a telephone pole lift-carry drill. All trainees underwent serial examinations, electrodiagnostic testing, and a comprehensive rehabilitation program.

RESULTS

Physical examination revealed universal weakness in flexion and abduction and electrodiagnostic studies confirmed injury to the C5-6 area of the brachial plexus (axillary, suprascapular, and musculocutaneous). All 11 patients were removed from training and started on a physical therapy program until functional recovery at a mean of 21 weeks after onset of symptoms (range, 12-24). All 11 resumed military activities; however, only 6 completed the Navy Basic Underwater Demolition School program.

CONCLUSION

In physically intense training or athletic environments, injuries to the upper brachial plexus may present with various forms of upper extremity dysfunction, including painless shoulder weakness. This information provides insight into a potentially debilitating shoulder problem and offers guidance on future training principles.

MR imaging evaluation of disorders of the chest wall

Chest wall lesions constitute a diverse group of thoracic diseases, including those of soft tissue and osseous origin. MR imaging, with its superior tissue-resolving capability and multiplanar image acquisition, is an important tool for assessing chest wall lesions. In this article, the authors review common and uncommon diseases of the chest wall, with an emphasis on the MR imaging characteristics of these diseases. Among the diseases they discuss are diseases of the soft tissue including lipoma, hibernoma, liposarcoma, hemangioma, and lymphoma. They also examine diseases of the osseous thorax, including benign osseous tumors, fibrous dysplasia, and aneurysmal bone cyst. In addition, they discuss such malignant osseous tumors as osteosarcoma and Ewing's sarcoma.

Development and validation of a standardized method for contouring the brachial plexus: preliminary dosimetric analysis among patients treated with IMRT for head-and-neck cancer

PURPOSE

Although Radiation Therapy Oncology Group protocols have proposed a limiting dose to the brachial plexus for patients undergoing intensity-modulated radiotherapy for head-and-neck cancer, essentially no recommendations exist for the delineation of this structure for treatment planning.

METHODS AND MATERIALS

Using anatomic texts, radiologic data, and magnetic resonance imaging, a standardized method for delineating the brachial plexus on 3-mm axial computed tomography images was devised. A neuroradiologist assisted with identification of the brachial plexus and adjacent structures. This organ at risk was then contoured on 10 consecutive patients undergoing intensity-modulated radiotherapy for head-and-neck cancer. Dose-volume histogram curves were generated by applying the proposed brachial plexus contour to the initial treatment plan.

RESULTS

The total dose to the planning target volume ranged from 60 to 70 Gy (median, 70). The mean brachial plexus volume was 33 +/- 4 cm(3) (range, 25.1-39.4). The mean irradiated volumes of the brachial plexus were 50 Gy (17 +/- 3 cm(3)), 60 Gy (6 +/- 3 cm(3)), 66 Gy (2 +/- 1 cm(3)), 70 Gy (0 +/- 1 cm(3)). The maximal dose to the brachial plexus was 69.9 Gy (range, 62.3-76.9) and was >/=60 Gy, >/=66 Gy, and >/=70 Gy in 100%, 70%, and 30% of patients, respectively.

CONCLUSIONS

This technique provides a precise and accurate method for delineating the brachial plexus organ at risk on treatment planning computed tomography scans. Our dosimetric analysis suggest that for patients undergoing intensity-modulated radiotherapy for head-and-neck cancer, brachial plexus routinely receives doses in excess of historic and Radiation Therapy Oncology Group limits.

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

BACKGROUND

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.

OBJECTIVE

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.

MATERIALS AND METHODS

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.

RESULTS

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).

CONCLUSION

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.

Diagnostic value and surgical implications of the magnetic resonance imaging in the management of adult patients with brachial plexus pathologies

The imaging of the brachial plexus (BP) cannot easily be achieved because of the extension of the region to be studied, the different tissue compositions of the adjacent anatomic structures and the necessity to work with thin tissue slices. Here is a description of the brachial plexus MRI (bpMRI) protocol that we use for the pre-operative evaluation of patients affected by the following brachial plexus (BP) pathologies: neoplastic, post-traumatic, inflammatory. The surgical implications are discussed. A survey was done on 115 patients (66 males; 49 females; mean age 46.4 years old), which underwent a bpMRI over a 32-month period (32 post-traumatic, 26 neoplastic, 25 affected by inflammatory diseases). Our bpMRI protocol is evaluated according to each mechanism of disease. The bpMRI provides a topographic localization of the tumour showing the nerve dislocations or infiltration by the neoplasm. In traumatic patients we suggest that the bpMRI could be useful to detect the degree of axonal damage when the nerve lesion is in continuity. We also consider the diagnosis and the possible surgical implications for the inflammatory plexopathies. In conclusion, a standardized bpMRI protocol has an invaluable diagnostic value for the surgeons and neurologists. It is only limited by its duration (at least 45 min).

The clinical applications of peripheral nerve imaging in the upper extremity

Use of different imaging modalities in the diagnosis of peripheral nerve pathology has been growing steadily. This review attempts to summarize their use, particularly with regard to ultrasound and magnetic resonance imaging, and their practical applications in the clinical setting.

Bilateral Neuralgic Amyotrophy Presenting with Left Vocal Cord and Phrenic Nerve Paralysis

This article reports the difference between neuralgic amyotrophy and neuropathy caused by chemotherapy and radiation treatment which manifested with severe shoulder pain followed by marked weakness of bilateral upper arms and involvement of cranial nerves. A 62-year-old man presented with acute severe neuropathic pain at the left shoulder, bilateral shoulder weakness, hoarseness of voice from vocal cord palsy, and respiratory insufficiency from left diaphragm palsy, which all occurred sequentially over a 1-month period. The diagnosis of neuralgic amyotrophy was supported and differentiated from tumor-induced and radiation-induced neuropathy by clinical presentation, electrophysiologic and imaging studies. Unlike previous reports of the onset of neuralgic amyotrophy being associated with initiation of radiation treatment in cancer patients, this report demonstrates that neuralgic amyotrophy can occur at any point of the malignant disease process after radiation and chemotherapy.

Non-traumatic brachial plexopathies, clinical, radiological and neurophysiological findings from a tertiary centre

OBJECTIVE

To establish the clinical characteristics, aetiology, neuro-physiological characteristics, imaging findings and other investigations in a cohort of patients with non-traumatic brachial plexopathy (BP).

METHODS

A 3-year retrospective study of patients with non-traumatic BP identified by electromyography (EMG) and nerve conduction studies (NCS). Clinical information was retrieved from patients' medical charts.

RESULTS

Twenty-five patients were identified. Causes of BP included neuralgic amyotrophy (NA) (48%), neoplastic (16%), radiation (8%), post infectious (12%), obstetric (4%), rucksack injury (4%), thoracic outlet syndrome (4%) and iatrogenic (4%). Patients with NA presented acutely in 50%. The onset was subacute in all others. Outcome was better for patients with NA. All patients with neoplastic disease had a previous history of cancer. MRI was abnormal in 3/16 patients (18.8%). PET scanning diagnosed metastatic plexopathy in two cases.

CONCLUSIONS

NA was the most common cause of BP in our cohort and was associated with a more favourable outcome. The authors note potentially discriminating clinical characteristics in our population that aid in the assessment of patients with brachial plexopathies. We advise NCS and EMG be performed in all patients with suspected plexopathy. Imaging studies are useful in selected patients.

Magnetic resonance imaging characteristics of peripheral nerve sheath tumors of the canine brachial plexus in 18 dogs

Magnetic resonance imaging (MRI) examinations from 18 dogs with a histologically confirmed peripheral nerve sheath tumor (PNST) of the brachial plexus were assessed retrospectively. Almost half (8/18) had a diffuse thickening of the brachial plexus nerve(s), six of which extended into the vertebral canal. The other 10/18 dogs had a nodule or mass in the axilla (1.2-338 cm3). Seven of those 10 masses also had diffuse nerve sheath thickening, three of which extended into the vertebral canal. The majority of tumors were hyperintense to muscle on T2-weighted images and isointense on T1-weighted images. Eight of 18 PNSTs had only minimal to mild contrast enhancement and many (13/18) enhanced heterogeneously following gadolinium DTPA administration. Transverse plane images with a large enough field of view (FOV) to include both axillae and the vertebral canal were essential, allowing in-slice comparison to detect lesions by asymmetry of structures. Higher resolution, smaller FOV, multiplanar examination of the cervicothoracic spine was important for appreciating nerve root and foraminal involvement. Short tau inversion recovery, T2-weighted, pre and postcontrast T1-weighted pulse sequences were all useful. Contrast enhancement was critical to detecting subtle diffuse nerve sheath involvement or small isointense nodules, and for accurately identifying the full extent of disease. Some canine brachial plexus tumors can be challenging to detect, requiring a rigorous multiplanar multi-pulse sequence MRI examination.

Brachial Plexus Injury: Clinical Manifestations, Conventional Imaging Findings, and the Latest Imaging Techniques

Brachial plexus injury (BPI) is a severe neurologic injury that causes functional impairment of the affected upper limb. Imaging studies play an essential role in differentiating between preganglionic and postganglionic injuries, a distinction that is crucial for optimal treatment planning. Findings at standard myelography, computed tomographic (CT) myelography, and conventional magnetic resonance (MR) imaging help determine the location and severity of injuries. MR imaging sometimes demonstrates signal intensity changes in the spinal cord, and enhancement of nerve roots and paraspinal muscles at MR imaging indicates the presence of root avulsion injuries. New techniques including MR myelography, diffusion-weighted neurography, and Bezier surface reformation can also be useful in the evaluation and management of BPI. MR myelography with state-of-the-art technology yields remarkably high-quality images, although it cannot replace CT myelography entirely. Diffusion-weighted neurography is a cutting-edge technique for visualizing postganglionic nerve roots. Bezier surface reformation allows the depiction of entire intradural nerve roots on a single image. CT myelography appears to be the preferred initial imaging modality, with standard myelography and contrast material-enhanced MR imaging being recommended as additional studies. Work-up will vary depending on the equipment used, the management policy of peripheral nerve surgeons, and, most important, the individual patient.

T1- and T2-weighted fast spin-echo imaging of the brachial plexus and cervical spine with IDEAL water–fat separation

PURPOSE

To compare the iterative decomposition of water and fat with echo asymmetry and least-squares estimation (IDEAL) method with fat-saturated T1-weighted (T1W) and T2W fast spin-echo (FSE) and short-TI inversion recovery (STIR) imaging of the brachial plexus and cervical spine.

MATERIALS AND METHODS

Images acquired at 1.5T in five volunteers using fat-saturated T1W and T2W FSE imaging and STIR were compared with T1W and T2W IDEAL-FSE images. Examples of T1W and T2W IDEAL-FSE images acquired in patients are also shown.

RESULTS

T1W and T2W IDEAL-FSE demonstrated superior fat suppression (P<0.05) and image quality (P<0.05), compared to T1W and T2W fat-saturated FSE, respectively. SNR performance of T1W-IDEAL-FSE was similar to T1W FSE in the spinal cord (P=0.250) and paraspinous muscles (P=0.78), while T2W IDEAL-FSE had superior SNR in muscle (P=0.02) and CSF (P=0.02), and marginally higher cord SNR (P=0.09). Compared to STIR, T2W IDEAL-FSE demonstrated superior image quality (P<0.05), comparable fat suppression (excellent, P=1.0), and higher SNR performance (P<0.001).

CONCLUSION

IDEAL-FSE is a promising method for T1W and T2W imaging of the brachial plexus and cervical spine.

Imaging the anatomy of the brachial plexus: review and self-assessment module

OBJECTIVE

The educational objectives of this continuing medical education activity are to describe the normal anatomy of the brachial plexus, to name the most common symptoms associated with a brachial plexopathy, to describe the most common imaging findings resulting from trauma to the brachial plexus, to describe the imaging manifestations of common neoplasias affecting the brachial plexus, and to also describe the imaging findings and symptoms related to irradiation-induced brachial plexopathies.

CONCLUSION

In this article, I have illustrated and described the normal anatomy of the brachial plexus; the most common symptoms related to brachial plexopathy; and imaging findings related to trauma, tumors, and irradiation affecting the brachial plexus.