Magnetic resonance neurography of the brachial plexus

The guiding value of the cinematic volume rendering technique in the preoperative diagnosis of brachial plexus schwannoma

This study aimed to explore and compare the guiding value of Maximum Intensity Projection (MIP) and Cinematic Volume Rendering Technique (cVRT) in the preoperative diagnosis of brachial plexus schwannomas. We retrospectively analyzed the clinical and imaging data of 45 patients diagnosed with brachial plexus schwannomas at the First Affiliated Hospital of Zhengzhou University between January 2020 and December 2022. The enhanced three-dimensional short recovery time inversion-recovery fast spin-echo imaging (3D-STIR-SPACE) sequence served as source data for the reconstruction of MIP and cVRT. Two independent observers scored the image quality and evaluated the location of the tumor and the relationship between the tumor and the brachial plexus. The image quality scores of the two reconstruction methods were compared using the nonparametric Wilcoxon signed-rank test, and the consistency between the image and surgical results was assessed using the weighted kappa. Compared to MIP images, cVRT images had a better performance of overall image quality (p < 0.001), nerve and lump visualization (p < 0.001), spatial positional relationship conspicuity (p < 0.001), and diagnostic confidence (p < 0.001). Additionally, the consistency between the cVRT image results and surgical results (kappa =0.913, P<0.001) was higher than that of the MIP images (kappa =0.829, P<0.001). cVRT provides a high guiding value in the preoperative diagnosis of brachial plexus schwannomas and is an important basis for formulating surgical plans.

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.

A Decade of Imaging Patients with Traumatic Brachial Plexopathy: What have We Learned?

Aim  In this paper, the authors share their experience of imaging patients with traumatic brachial plexopathy by magnetic resonance neurography (MRN) spanning over a period of nearly 10 years. Setting and Design  This was a single-institution, prospective, observational study conducted between August 2012 and March 2022. Materials and Methods  Children and adults presenting to the plastic surgery outpatient department with features of traumatic brachial plexopathy were included in the study. The MRN study was performed in a 1.5T scanner (Magnetom Essenza, Siemens, Erlangen, Germany). The area scanned extended from C3 level to T3 level. Statistical Analysis Descriptive statistics (percentages, mean, median, and mode). Results  A total of 134 patients ( n  = 134) were included in the study. The age of our patients ranged from 6 months to 65 years. The mean age was 24.95 ± 12.10 years, with a median of 23 years. All patients had unilateral injury, and the right side was more commonly involved. Road traffic accident was the most common mode of injury, and blunt crush-avulsion was the most common mechanism of injury. Involvement of shoulder, elbow, and hand together (panplexopathy) was the most common clinical presentation. Conclusion  This study of patients with traumatic brachial plexopathy imaged by MRN, spanning nearly a decade, has led to several interesting observations. The majority of these injuries occur in young men from urban areas who usually present with panplexopathy. The most common mode of injury is road traffic accident, and blunt crush-avulsion is the most common mechanism of injury.

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.

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

Background

Management 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.

Results

MRN 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).

Conclusion

MRN 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.

Magnetic Resonance Neurography for Evaluation of Peripheral Nerves

Peripheral nerve injuries (PNIs) continue to present both diagnostic and treatment challenges. While nerve transections are typically a straightforward diagnosis, other types of PNIs, such as chronic or traumatic nerve compression, may be more difficult to evaluate due to their varied presentation and limitations of current diagnostic tools. As a result, diagnosis may be delayed, and these patients may go on to develop progressive symptoms, impeding normal activity. In the past, PNIs were diagnosed by history and clinical examination alone or techniques that raised concerns regarding accuracy, invasiveness, or operator dependency. Magnetic resonance neurography (MRN) has been increasingly utilized in clinical settings due to its ability to visualize complex nerve structures along their entire pathway and distinguish nerves from surrounding vasculature and tissue in a noninvasive manner. In this review, we discuss the clinical applications of MRN in the diagnosis, as well as pre- and postsurgical assessments of patients with peripheral neuropathies.

MR neurography in Parsonage-Turner syndrome

Background and Aims:

Parsonage Turner Syndrome is a well known clinical entity. Several excellent articles have succinctly described Magnetic Resonance Imaging (MRI) findings in PTS. However, these articles have inferred neural involvement in PTS based on the patterns of denervation of muscles in the shoulder region. The aim of this study is to directly visualize the distribution and extent of abnormality in MR Neurography (MRN) of the brachial plexus in known cases of brachial plexus neuritis or Parsonage-Turner Syndrome (PTS).

Methods:

15 patients who were diagnosed with PTS based on clinical and electrophysiological findings participated in the study. MRN of the brachial plexus was done in a 1.5T system using a combination of T1W (T1-weighted), T2W (T2-weighted) fat-saturated, STIR (Short Tau Inversion Recovery), 3D STIR SPACE (Sampling Perfection with Application Optimized Contrasts) and 3D T2W SPACE sequences. Findings were recorded and assessed.

Results:

The age range of our patients was 7-65 years (mean 37.87 years). Most of the patients had unilateral symptoms. All patients had weakness in shoulder abduction. Other common associated complaints included pain in the shoulder/neck/arm and preceding fever. MRN revealed the percentage of involvement of roots, trunks, cords and terminal branches was 53.3%, 46.7%, 40% and 13.3% respectively. Evidence of muscle denervation in the form of edema, fatty infiltration and atrophy was noted in 8 (53.3%) patients.

Conclusion:

Most of the patients in this study had unilateral involvement on MRN. The roots were the commonest site of involvement followed by the trunks, cords and terminal branches. C5 was the most commonly involved root.

MR neurography in traumatic, non-obstetric paediatric brachial plexopathy

OBJECTIVES

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.

METHODS

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.

RESULTS

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%).

CONCLUSIONS

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.

KEY POINTS

• 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.