MRI findings in thoracic outlet syndrome

Thoracic Outlet Syndrome

ABSTRACT

Thoracic outlet syndrome is a complex syndrome that manifests with symptoms based on the presumed injury or impairment of the neurovascular structures in the thoracic outlet space with its intricate anatomy and pathophysiology. The thoracic outlet is a specific anatomical region with three distinct anatomical spaces - interscalene triangle, the costoclavicular space, and the retro-pectoralis minor space. Thoracic outlet syndrome is classified into neurogenic, venous, and arterial thoracic outlet syndrome and often poses diagnostic challenge to implicate a specific condition or cause. Many cases of thoracic outlet syndrome can be effectively managed through conservative measures, but patients with refractory symptoms may warrant surgical intervention. Modalities such as intramuscular anesthetic and botulinum toxin injections hold promise as diagnostic, therapeutic, and prognostic procedures. Further research and collaboration are needed to develop algorithms for diagnosis and treatment of thoracic outlet syndrome symptoms. This review aims to explore our understanding of thoracic outlet syndrome, with a focus on current evidence and emerging trends.

The role of imaging in focal neuropathies

Electrodiagnostic testing (EDX) has been the diagnostic tool of choice in peripheral nerve disease for many years, but in recent years, peripheral nerve imaging has been used ever more frequently in daily clinical practice. Nerve ultrasound and magnetic resonance (MR) neurography are able to visualize nerve structures reliably. These techniques can aid in localizing nerve pathology and can reveal significant anatomical abnormalities underlying nerve pathology that may have been otherwise undetected by EDX. As such, nerve ultrasound and MR neurography can significantly improve diagnostic accuracy and can have a significant effect on treatment strategy. In this chapter, the basic principles and recent developments of these techniques will be discussed, as well as their potential application in several types of peripheral nerve disease, such as carpal tunnel syndrome (CTS), ulnar neuropathy at the elbow (UNE), radial neuropathy, brachial and lumbosacral plexopathy, neuralgic amyotrophy (NA), fibular, tibial, sciatic, femoral neuropathy, meralgia paresthetica, peripheral nerve trauma, tumors, and inflammatory neuropathies.

Magnetic resonance imaging for diagnosis of suspected neurogenic thoracic outlet syndrome-a systematic scoping review

Background: Neurogenic Thoracic Outlet Syndrome (nTOS) is a rare pathology caused by dynamic conditions or compression of neurovascular structures in the thoracic outlet region. nTOS can be difficult to diagnose due to nonspecific symptoms and magnetic resonance imaging (MRI) techniques are increasingly used to aid the diagnosis and surgical planning. This scoping systematic review explores how MRI is used for diagnosing nTOS and summarizes details of published MRI protocols. Methods: A systematic screening of PubMed, Cochrane, Web of Science, and CINAHL databases using PRISMA-IPD guidelines was conducted in September 2022 to include full-text English papers on MRI and nTOS. Inclusion criteria involved studies describing MRI protocols for the diagnosis of TOS, with a focus on the imaging sequences and protocols. Results: 6289 papers were screened to include 28 papers containing details of MRI protocols. The details of MRI protocols in the analyzed articles were incomplete in all studies. Most authors used 1.5T systems and included T1 and T2-weighted sequences. Most studies applied fat suppression, mainly with STIR. Positioning of the arm differed between studies, including neutral, hyperabducted and abducted and externally rotated positions. Conclusion: Our review highlights a prevalent lack of detailed MRI protocol documentation for brachial plexus. Authors primarily rely on conventional 1.5T systems, employing standard T1 and T2-weighted sequences. The adoption of novel MRI sequences is notably lacking, and fat suppression techniques predominantly adhere to older methods as STIR. There is a clear imperative for authors to provide more comprehensive reporting of the MRI protocols utilized in their studies, ultimately enhancing comparability and clinical applicability. Establishing clear protocol reporting guidelines is crucial to allow for comparison between studies.

Bakody's Test Positive Thoracic Outlet Syndrome Caused by Anomalous Muscle: A Case Report

Anomalous muscle causes thoracic outlet syndrome (TOS). A 40-year-old man presented with numbness of the left upper extremity, similar to cervical spondylotic radiculopathy. He presented with a positive Bakody's test. However, magnetic resonance imaging showed no significant changes in the cervical spine and revealed an anomalous muscle adjacent to the left brachial plexus. We diagnosed the muscle as the cause of TOS and performed a resection, which resulted in symptomatic improvement.

Comparison of duplex ultrasound and hemodynamic assessment with computed tomography angiography in patients with arterial thoracic outlet syndrome

Thoracic outlet syndrome (TOS) presents with a variety of neurovascular symptoms, and its diagnosis cannot be established purely on the basis of clinical assessments. Computed tomography angiography (CTA) is currently the most useful investigative modality for patients with suspected vascular TOS. However, CTA facilities are limited, and CTA itself is an expensive and a resource-intensive technique associated with risks such as radiation exposure and contrast toxicity. Therefore, a screening test to identify the need for CTA may facilitate clinical management of patients with suspected TOS. Data for patients with suspected arterial TOS who underwent duplex ultrasound with arterial hemodynamic assessment (HDA) (pulse-volume recording and Doppler arterial pressure measurement) at King Saud University Medical City Vascular Lab between 2009 and 2018 were collected. The sensitivity, specificity, positive and negative predictive values (NPV), and area under the curve for duplex ultrasound and arm arterial HDA with CTA were reviewed. The data for 49 patients (mean age, 31 ± 14 years) were reviewed, of which 71% were female. The sensitivity, specificity, positive predictive value, and NPV of duplex ultrasound were 86.7%, 49.3%, 26.5%, and 94.6%, respectively. For arm arterial HDA, these values were 73.3%, 78.9%, 42.3%, and 93.3%, respectively. The combination of arm arterial HDA with duplex ultrasound scores yielded sensitivity, specificity, positive predictive value, and NPV of 93.3%, 42.3%, 25.5%, and 96.8%, respectively. The combination of duplex ultrasound with arm arterial HDA showed higher sensitivity and NPV than either test alone. The specificity of arm arterial HDA was significantly higher than that of the other measurements. When suspected, arterial TOS could be ruled out using duplex ultrasound and arm arterial HDA. These 2 investigations may help determine the need for CTA.

Thoracic Outlet Syndrome Part I: Systematic Review of the Literature and Consensus on Anatomy, Diagnosis, and Classification of Thoracic Outlet Syndrome by the European Association of Neurosurgical Societies' Section of Peripheral Nerve Surgery

BACKGROUND

Although numerous articles have been published not only on the classification of thoracic outlet syndrome (TOS) but also on diagnostic standards, timing, and type of surgical intervention, there still remains some controversy because of the lack of level 1 evidence. So far, attempts to generate uniform reporting standards have not yielded conclusive results.

OBJECTIVE

To systematically review the body of evidence and reach a consensus among neurosurgeons experienced in TOS regarding anatomy, diagnosis, and classification.

METHODS

A systematic literature search on PubMed/MEDLINE was performed on February 13, 2021, yielding 2853 results. Abstracts were screened and classified. Recommendations were developed in a meeting held online on February 10, 2021, and refined according to the Delphi consensus method.

RESULTS

Six randomized controlled trials (on surgical, conservative, and injection therapies), 4 "guideline" articles (on imaging and reporting standards), 5 observational studies (on diagnostics, hierarchic designs of physiotherapy vs surgery, and quality of life outcomes), and 6 meta-analyses were identified. The European Association of Neurosurgical Societies' section of peripheral nerve surgery established 18 statements regarding anatomy, diagnosis, and classification of TOS with agreement levels of 98.4 % (±3.0).

CONCLUSION

Because of the lack of level 1 evidence, consensus statements on anatomy, diagnosis, and classification of TOS from experts of the section of peripheral nerve surgery of the European Association of Neurosurgical Societies were developed with the Delphi method. Further work on reporting standards, prospective data collections, therapy, and long-term outcome is necessary.

Combined nerve and vascular ultrasound in thoracic outlet syndrome: A sensitive method in identifying the site of neurovascular compression

We investigated the diagnostic utility of combined nerve and vascular ultrasound in thoracic outlet syndrome (TOS) in a retrospective cohort study on two sites, involving 167 consecutive patients with the clinical symptoms suggestive of neurogenic and/or vascular TOS, and an age- and sex-matched control group. All patients and control subjects underwent nerve ultrasound of the supraclavicular brachial plexus to look for fibromuscular anomalies / compression of the brachial plexus in the scalenic region, and vascular ultrasound of the infraclavicular subclavian artery with the arm in neutral and abducted position, serving as an indicator for costoclavicular compression of the neurovascular bundle. Based on clinical symptoms, neurogenic TOS (81%) was the most frequent type of TOS, followed by combined neurogenic and arterial TOS (8%). The frequency of abnormal nerve and/or vascular ultrasound findings differed significantly from the control group (P<0.00001). The pooled sensitivity was 48% for nerve ultrasound, 85% for vascular ultrasound, and 94% when combined. Among the findings, the fibromuscular ‘wedge-sickle sign’, indicating compression of the lower trunk in the scalenic region by a congenital fibromuscular anomaly (e.g. Roos ligaments), showed the highest specificity (100%). A bony ‘wedge-sickle sign’ was also delineated, where lower trunk compression is caused by the neck of the 1^st rib. As implied by the higher sensitivity of vascular ultrasound, the most common site of compression was the costoclavicular space, but multilevel compression was also frequently observed. In summary, combined nerve and vascular ultrasound is a sensitive and reliable method to support the diagnosis of TOS. It can also identify the site(s) of compression, with obvious therapeutic consequences.

Thoracic Outlet Syndrome: Single Center Experience on Robotic Assisted First Rib Resection and Literature Review

BACKGROUND

Thoracic outlet syndrome (TOS) is a pathological condition caused by a narrowing between the clavicle and first rib leading to a compression of the neurovascular bundle to the upper extremity. The incidence of TOS is probably nowadays underestimated because the diagnosis could be very challenging without a thorough clinical examination along with appropriate clinical testing. Beside traditional supra-, infraclavicular or transaxillary approaches, the robotic assisted first rib resection has been gaining importance in the last few years.

METHODS

We conducted a retrospective cohort analysis of all patients who underwent robotic assisted first rib resection due to TOS at Lucerne Cantonal Hospital and then we performed a narrative review of the English literature using PubMed, Cochrane Database of Systematic Reviews and Scopus.

RESULTS

Between June 2020 and November 2021, eleven robotic assisted first rib resections were performed due to TOS at Lucerne Cantonal Hospital. Median length of stay was 2 days (Standard Deviation: +/- 0.67 days). Median surgery time was 180 min (Standard Deviation: +/- 36.5). No intra-operative complications were reported.

CONCLUSIONS

Robotic assisted first rib resection could represent a safe and feasible option in expert hands for the treatment of thoracic outlet syndrome.

Novel Use of Ali Shahab Score as a Diagnostic Tool and Decision of Surgical Management in Scalenus Syndrome: A Case Series

BACKGROUND: Scalenus syndrome is a collection of symptoms as the consequences of nerve and vascular compression within the scalene triangle. However, the entity has long been forgotten in publications and is difficult to recognize. The diagnosis of scalenus syndrome is mainly based on clinical findings. The Ali Shahab score is a new scoring system, generated based on clinical symptoms of scalenus syndrome. AIM: In this study, we presented a case series of scalenus syndrome patients who were diagnosed and decide to be managed surgically based on Ali Shahab score. We also reported post-operative outcomes following scalenectomy in our series. METHODS: This was a case series including patients with scalenus syndrome in Gatot Soebroto Army Hospital, Indonesia, and Siloam Asri Hospital, Indonesia, between 2016 and 2021. The diagnosis of scalenus syndrome was made based on Ali Shahab score with a value of more than 7. All patients were performed scalenectomy to decompress the stenotic subclavian artery and brachial plexus from surrounding fibrotic tissue. Eligible subjects were assessed for sex, side of symptoms, pre-operative and post-operative Ali Shahab score, and post-operative outcome. RESULTS: We included 96 patients with scalenus syndrome in this case series. Most of the included patients were male (59.4%) and experienced scalenus syndrome on the right side (76%). The average pre-operative Ali Shahab score in our series was 7.12 ± 0.48 and the post-operative score was 0.11 ± 0. Regarding post-operative outcomes, more than half of the patients experienced symptoms reduction with 38.5% of patients experiencing complete resolution of symptoms following scalenectomy. CONCLUSION: The application of the Ali Shahab score may be used as a diagnostic tool and decision of surgical management for scalenus syndrome patients. Decompression of the subclavian artery and releasing brachial plexus from surrounding fibrotic tissue can improve clinical symptoms in scalenus syndrome patients.

Update on the thoracic outlet syndrome and plexus brachial syndrome: Specific clinical examination (for all) and rehabilitation protocol

The diagnosis of uncomplicated forms of thoracobrachial outlet syndrome (TOS) and brachial plexus stretching syndrome (BPSS) is imprecise due to the lack of clear differentiation between dynamic vascular or neurological compression and brachial plexus stretching without vascular compression. After a review of literature, we propose and describe a simple way for clinical assessment of TOS, BPSS or association of both comprising 1 clinical sign and 2 manoeuvres. This clinical assessment can be performed by the medical doctor, the physiotherapist and the surgeon. The clinical diagnosis is essential because it will dictate the rehabilitation treatment. We propose and describe also a rehabilitation protocol comprising 10 phases with modulation of exercises according to clinical form (TOS, BPSS or association) and/or severity of symptoms. The physiotherapist has a capital role and is the guarantor of the effectiveness of the medical treatment. In France, a training is now available thanks to personal continuous development for diagnosis and treatment of TOS and BPSS. This is essential in order to propose an optimal care to patients.

Evaluation and Management of Arterial Thoracic Outlet Syndrome

Arterial thoracic outlet syndrome is rare and may be associated with a bony anomaly. Patient presentation can range from mild arm discoloration and claudication to severe limb-threatening ischemia. For patients with subclavian artery dilation without secondary complications, thoracic outlet decompression and arterial surveillance is sufficient. Patients with subclavian artery aneurysms or distal embolization require decompression with reconstruction or thromboembolectomy and distal bypass respectively.

ACR Appropriateness Criteria® Thoracic Outlet Syndrome

Thoracic outlet syndrome (TOS) is the clinical entity that occurs with compression of the brachial plexus, subclavian artery, and/or subclavian vein at the superior thoracic outlet. Compression of each of these structures results in characteristic symptoms divided into three variants: neurogenic TOS, venous TOS, and arterial TOS, each arising from the specific structure that is compressed. The constellation of symptoms in each patient may vary, and patients may have more than one symptom simultaneously. Understanding the various anatomic spaces, causes of narrowing, and resulting neurovascular changes is important in choosing and interpreting radiological imaging performed to help diagnose TOS and plan for intervention. This publication has separated imaging appropriateness based on neurogenic, venous, or arterial symptoms, acknowledging that some patients may present with combined symptoms that may require more than one study to fully resolve. Additionally, in the postoperative setting, new symptoms may arise altering the need for specific imaging as compared to preoperative evaluation. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Thoracic Outlet Syndrome: Diagnostic Accuracy of MRI

BACKGROUND

Thoracic outlet syndrome (TOS) is challenging to diagnose, as the physical findings and investigations lack sensitivity and/or specificity. Magnetic resonance imaging (MRI) with dynamic manoeuvres can rule out a tumour and detect anatomical abnormalities potentially responsible for compression. The objective of this study was to assess the sensitivity and specificity of MRI for identifying anatomical structures responsible for compression in TOS, using intra-operative findings as the diagnostic reference standard.

HYPOTHESIS

MRI is effective in diagnosing the source of compression in TOS, notably within the scalene triangle and at the pleural apex.

METHODS

We retrospectively included 48 patients who underwent surgery for TOS after a work-up that included MRI (1.5-T, n=29 and 3-T, n=19). The MRI scans were reviewed for the study by a specialised radiologist who was unaware of the intra-operative findings. The sensitivity and specificity of MRI for diagnosing TOS were estimated using the intra-operative findings as the reference standard.

RESULTS

MRI identified a structure potentially responsible for TOS in 34 (71%) patients; thus, the false-negative rate was 14/48 (29%). The sensitivity of MRI was 28% for compression at the suspensory ligament of the pleural dome, 81% for hypertrophy of the anterior scalene muscle, and 50% for an accessory scalene muscle. For diagnosing a cervical rib, MRI had 100% sensitivity and 100% specificity.

CONCLUSION

MRI can contribute to the diagnosis of TOS. Specificity is sufficiently high to provide guidance for planning the surgical procedure. Sensitivity, however, is too low for MRI to be useful as a screening test. MRI should be used in combination with the clinical assessment and other investigations to assist in the diagnosis of TOS.

LEVEL OF EVIDENCE

IV, retrospective cohort study.

Improved functional outcome in NTOS patients following resection of the subclavius muscle with radiological signs of nerve impingement: indication of participation of the subclavius in brachial plexus compression

OBJECTIVE

Both clinical and radiological reports have suggested that the subclavius, a muscle in the costoclavicular space of the thoracic outlet, participates in neurogenic thoracic outlet syndrome (NTOS) in some instances, especially during movements narrowing the costoclavicular space. Magnetic resonance imaging can identify subclavius muscles with signs of nerve impingement, yet the impact of the subclavius in such situations remains unclear. Therefore, the authors investigated whether dividing or sparing the subclavius characterized by nerve impingement on MRI would affect surgical outcomes.

METHODS

In this retrospective nonrandomized study, authors analyzed all NTOS patients with a subclavius muscle characterized by nerve impingement on MRI (loss of normal fat planes surrounding the brachial plexus) in the period between March 2010 and November 2016. Patients were divided into two groups: the sparing group, in which patients had undergone conventional supraclavicular scalenectomy and first rib resection (FRR), and the dividing group, in which patients had undergone scalenectomy, FRR, and subclavius dividing using a modified supraclavicular incision. The Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire, a shoulder range of motion subscale (DASH items 6, 12-15, and 19) concerning overhead activities that can significantly narrow the costoclavicular space, postoperative MRI studies, and patient self-assessments were used to assess surgical outcomes. Univariate and multivariate analyses were conducted to identify independent factors associated with subscale scores.

RESULTS

From a total of 261 patients screened, 71 were eligible for study inclusion. Compared with the sparing group (33 patients), the dividing group (38 patients) had similar postoperative DASH scores and self-assessments but better subscale scores (9.50 ± 2.76 vs 11.94 ± 2.87, p = 0.0005). Postoperative MRI on hyperabduction showed that the brachial plexus became surrounded by normal fat tissue in the costoclavicular space in the diving group but still had signs of impingement from the untreated subclavius muscle in the sparing group. This observation agreed with a better functional recovery in terms of overhead activities in the dividing group, which was reflected by better subscale scores. Multivariate analyses indicated that the type of treatment and symptom duration prior to surgery influenced the subscale scores independently.

CONCLUSIONS

This study revealed that an untreated radiological nerve-compressing subclavius muscle could lead to a relatively lower degree of recovery in the ability to perform overhead activities for NTOS patients postoperatively, suggesting that such subclavius muscles may participate in positional brachial plexus compression during movements narrowing the costoclavicular space. Dividing the muscles could decompress the costoclavicular space more effectively and may lead to better functional recovery.

Diagnosing Thoracic Outlet Syndrome: Current Approaches and Future Directions

The diagnosis of thoracic outlet syndrome (TOS) has long been a controversial and challenging one. Despite common presentations with pain in the neck and upper extremity, there are a host of presenting patterns that can vary within and between the subdivisions of neurogenic, venous, and arterial TOS. Furthermore, there is a plethora of differential diagnoses, from peripheral compressive neuropathies, to intrinsic shoulder pathologies, to pathologies at the cervical spine. Depending on the subdivision of TOS suspected, diagnostic investigations are currently of varying importance, necessitating high dependence on good history taking and clinical examination. Investigations may add weight to a diagnosis suspected on clinical grounds and suggest an optimal management strategy, but in this changing field new developments may alter the role that diagnostic investigations play. In this article, we set out to summarise the diagnostic approach in cases of suspected TOS, including the importance of history taking, clinical examination, and the role of investigations at present, and highlight the developments in this field with respect to all subtypes. In the future, we hope that novel diagnostics may be able to stratify patients according to the exact compressive mechanism and thereby suggest more specific treatments and interventions.

Dynamic CT angiography for the diagnosis of patients with thoracic outlet syndrome: Correlation with patient symptoms

INTRODUCTION

Vasculo-nervous structures serving the upper limbs may be compressed as they pass through three areas: the inter-scalene triangle (IST), the costo-clavicular space (CCS) and the retropectoralis minor space (RMS). The diagnosis of thoracic outlet syndrome (TOS) is essentially clinical, but requires imaging to specify the site of compression, its grade and the existence of predisposing anatomical factors, in order to guide the treatment and eliminate the main differential diagnoses.

MATERIAL AND METHODS

Images from 141 patients who underwent dynamic CT angiography of the thoracic outlets from June 2008 to January 2015 were analyzed retrospectively. Patients had unilateral or bilateral vascular, neurological, mixed or atypical symptoms. We studied the degree of stenosis of the subclavian artery with the following grading system: 1 (0-<25%), 2 (25-<50%), 3 (50-<75%), 4 (75-100%). The site of stenosis and the presence of underlying anatomical predisposing factors were also taken in account.

RESULTS

A total of 221 thoracic outlets were analyzed. Symptoms were neurological, mixed, vascular and atypical in 30%, 28%, 13% and 12%, respectively. Among patients with bilateral acquisitions, 38 outlets were asymptomatic; 40% of symptomatic outlets and only 5% of asymptomatic ones had grade 3 or 4 stenosis. 63% of the stenosis were in the CCS and 37% in the IST; 21% had a predisposing anatomical factor most often a costo-clavicular anomaly, associated with significant stenosis in 50% of cases.

CONCLUSION

Vascular stenosis of more than 50% on dynamic CT angiography is strongly associated with TOS. Predisposing factors were present in 21% of cases, causing significant vascular stenosis in half, underscoring the need for functional evaluation.

MRI of thoracic outlet syndrome in children

Thoracic outlet syndrome is caused by compression of the neurovascular bundle as it passes from the upper thorax to the axilla. The neurovascular bundle can be compressed by bony structures such as the first rib, cervical ribs or bone tubercles, or from soft-tissue abnormalities like a fibrous band, muscle hypertrophy or space-occupying lesion. Thoracic outlet syndrome commonly affects young adults but can be seen in the pediatric age group, especially in older children. Diagnosis is based on a holistic approach encompassing clinical features, physical examination findings including those triggered by various maneuvers, electromyography, nerve conduction studies and imaging. Imaging is performed to confirm the diagnosis, exclude mimics and classify thoracic outlet syndrome into neurogenic, arterial, venous or mixed causes. MRI and MR angiography are useful in this process. A complete MRI examination for suspected thoracic outlet syndrome should include the assessment of anatomy and any abnormalities using routine sequences, vessel assessment with the arms in adduction by MR angiography and assessment of dynamic compression of vessels with abduction of the arms. The purpose of this paper is to describe the anatomy of the thoracic outlet, causes of thoracic outlet syndrome, the MR imaging techniques used in its diagnosis and the principles of image interpretation.

Use of blood pool agents with steady-state MRI to assess the vascular system

Over the past two decades there have been significant advances in the use of magnetic resonance imaging (MRI) to assess the vascular system. New imaging sequences and improvements in magnet design have enabled the creation of higher spatial resolution images. MRI is now a viable alternative imaging modality when compared to both invasive angiography and computed tomographic angiography. The use of blood pool agents has further facilitated the use of MR angiography (MRA); their high molecular weight allows for lower doses of contrast medium administration while their prolonged presence in the blood stream allows for repeated high-quality volumetric imaging of both the arterial and venous circulation. As such, MRA is now no longer constrained by the tight windows for first-pass arterial and venous enhancement, which has resulted in the ability to assess and diagnose a large range of vascular pathologies in both arterial and venous systems. The intent of this review is to highlight MRI findings in common vascular pathologies including peripheral arterial disease (PAD), abnormalities of the abdominal aortic branches, postendovascular aortic aneurysm repair (EVAR) endoleak assessment, popliteal artery entrapment syndrome (PAES), deep venous thrombosis (DVT), vascular thoracic outlet syndrome (TOS), and vascular malformations. In addition, the latest MRI techniques currently used to optimally assess each of these pathologies will be discussed.

LEVEL OF EVIDENCE

5 Technical Efficacy: Stage 3 J. MAGN. RESON. IMAGING 2017;45:1559-1572.

Ultrasonographic Identification of Fibromuscular Bands Associated with Neurogenic Thoracic Outlet Syndrome: The "Wedge-Sickle" Sign

Thoracic outlet syndrome (TOS) is a disorder characterized by compression of the lower trunk of the brachial plexus, most often in association with anomalous congenital fibromuscular bands in the scalenic region. Early diagnosis is important, because the neurologic deficit associated with TOS may be irreversible. Using high-resolution ultrasound, we investigated 20 consecutive patients with clinical signs suggestive of TOS (all females, average age: 40.4 ± 14.9 y) and 25 control patients. In 19 patients, we identified a hyper-echoic fibromuscular structure at the medial edge of the middle scalene muscle, which indented the lower trunk of the brachial plexus ("wedge-sickle sign"). It was associated with the significant enlargement (p < 0.0001) and hypo-echogenicity of the lower trunk. This novel and distinctive ultrasonographic sign allows pre-surgical identification of anomalous fibromuscular bands causing TOS. It is especially useful in patients without neurologic deficit, in whom the diagnosis may not be as straightforward.

Magnetic Resonance Angiography of the Upper Extremity

The magnetic resonance angiography (MRA) toolbox includes a wide array of versatile methods for diagnosis and therapy planning in patients with a variety of upper extremity vascular pathologies. MRA can provide excellent image quality with high spatial and high temporal resolution without the disadvantages of ionizing radiation, iodinated contrast, and operator dependency. Contrast-enhanced techniques are preferred for their robustness, image quality, and shorter scan times. This article provides an overview of the available MRA techniques and a description of the clinical entities that are well suited for evaluation with contrast-enhanced MRA.

Pediatric Chest MR Imaging: Sedation, Techniques, and Extracardiac Vessels

Thoracic MR imaging in the pediatric population provides unique challenges requiring tailored protocols and a practical approach to pediatric issues, such as patient motion and sedation. Concern regarding the use of ionizing radiation in the pediatric population has continued to advance the use of MR imaging despite these challenges. This article provides a practical approach to thoracic vascular MR imaging with special attention paid to pediatric-specific issues such as sedation. Thoracic vascular anatomy and pathology are discussed with an emphasis on protocols that can facilitate accurate diagnosis.

Reference Values for the Scalene Interval Width During Varying Degrees of Glenohumeral Abduction Using Ultrasonography

OBJECTIVE

The aim of this study was to establish reference values for the width of the interval between the anterior and middle scalene muscles using ultrasonography during varying degrees of glenohumeral joint (GH) abduction. Reliability and body mass index (BMI) data were also assessed.

METHODS

Interscalene triangles of asymptomatic participants were scanned bilaterally in the transverse plane. Images were obtained at 0°, 90°, and 150° of GH abduction with the participant seated. Width measurements were taken between the anterior and middle scalene muscle borders by bisecting the C6 nerve root as it passed superficial to the posterior tubercle of the C7 transverse process. Intra- and interexaminer reliability and BMI correlation were studied. Statistical significance was defined as P ≤ .05.

RESULTS

Images of 42 scalene intervals were included from 21 participants (11 female). Mean participant age was 25.3 ± 3.9 years; mean BMI was 25.4 ± 2.7 kg/m². Scalene interval measurements at 0°, 90°, and 150° of GH abduction were 4.5 ± 0.5 mm, 4.6 ± 0.5 mm, and 4.4 ± 0.7 mm, respectively, without a significant difference (P = .07). Intraexaminer reliability was excellent (0°: intraclass correlation coefficient [ICC] = 0.82; 90°: ICC = 0.89; 150°: ICC = 0.90). Interexaminer reliability was good to excellent (0°: ICC = 0.59; 90°: ICC = 0.85; 150°: ICC = 0.89). Body mass index was positively correlated only at 0° of GH abduction.

CONCLUSIONS

This study establishes previously unreported reference ultrasonography values for the width of the scalene interval. Intraexaminer reliability was excellent at all glenohumeral positions, and interexaminer reliability was determined to be good to excellent. Body mass index was positively correlated only at 0° of GH abduction.

Thoracic outlet syndrome

Thoracic outlet syndrome is a well-described disorder caused by thoracic outlet compression of the brachial plexus and/or the subclavian vessels. Neurogenic thoracic outlet syndrome is the most common manifestation, presenting with pain, numbness, tingling, weakness, and vasomotor changes of the upper extremity. Vascular complications of thoracic outlet syndrome are uncommon and include thromboembolic phenomena and swelling. The clinical presentation is highly variable, and no reproducible study exists to confirm the diagnosis; instead, the diagnosis is based on a physician's judgment after a meticulous history and physical examination. Both nonsurgical and surgical treatment methods are available for thoracic outlet syndrome. Whereas nonsurgical management appears to be effective in some persons, surgical treatment has been shown to provide predictable long-term cure rates for carefully selected patients. In addition, physicians who do not regularly treat patients with thoracic outlet syndrome may not have an accurate view of this disorder, its treatment, or the possible success rate of treatment.

Neurologic thoracic outlet syndrome: summarizing a complex history and evolution

Thoracic outlet syndrome (TOS) is a blanket term encapsulating many different clinical entities. Neurologic or neurogenic TOS (NTOS) is its main contributor, but it remains a complicated and sometimes controversial entity. NTOS incorporates numerous types, etiologies, clinical presentations, diagnostic findings, and therapeutic modalities. This article reviews the spectrum of disease within the thoracic outlet that affects the brachial plexus, with a special emphasis on the commonly afflicted sports medicine patient.

A content analysis of cognitive and affective uses of patient support groups for rare and uncommon vascular diseases: comparisons of may thurner, thoracic outlet, and superior mesenteric artery syndrome

Rare disease patients are the predominant group of patients who are now connecting online to patient support groups, yet research on their uses of support groups has received little attention. This is a content analysis of three vascular diseases of differing degrees of rarity. Wall posts from Facebook patient support groups for May Thurner syndrome, thoracic outlet syndrome, and superior mesenteric artery syndrome were analyzed over a period of two years. Using Uses and Gratifications as the theoretical framework, the study purpose was to assess how variations in health condition and rarity of condition affect online support group user needs. Results indicated common main cognitive and affective uses across conditions, indicating a consistent pattern of needs communicated by all patients. However, there were nuanced differences in subcategories of cognitive and affective uses between the most and least rare disorders, which inform areas for tailored support mechanisms. Additionally, these vascular patients used their respective support groups primarily for cognitive reasons, especially for the rarest conditions, which informs of basic medical informational needs these patients face related to tests, treatment, surgery, and diagnoses.

NTOS symptoms and mobility: a case study on neurogenic thoracic outlet syndrome involving massage therapy

Neurogenic thoracic outlet syndrome (NTOS) is a neuromuscular condition affecting brachial plexus functionality. NTOS is characterized by paresthesia, pain, muscle fatigue, and restricted mobility in the upper extremity. This study quantified massage therapy's possible contribution to treatment of NTOS. A 24-year-old female with NTOS received eight treatments over 35 days. Treatment included myofascial release, trigger point therapy, cross fiber friction, muscle stripping, and gentle passive stretching. Abduction and lateral rotation at the glenohumeral (GH joint) assessments measured range of motion (ROM). A resisted muscle test evaluated upper extremity strength. The client rated symptoms daily via a visual analog scale (VAS). Findings showed improvement in ROM at the GH joint. VAS ratings revealed a reduction in muscle weakness, pain, numbness, and 'paresthesia'. Results suggest massage may be useful as part of a broad approach to managing NTOS symptoms and improving mobility.