A Novel Approach for Imaging of Thoracic Outlet Syndrome Using Contrast-Enhanced Magnetic Resonance Angiography (CE-MRA), Short Inversion Time Inversion Recovery Sampling Perfection with Application-Optimized Contrasts Using Different Flip Angle Evolutions (T2-STIR-SPACE), and Volumetric Interpolated Breath-Hold Examination (VIBE)

Utility of contrast-enhanced 3D STIR FLAIR imaging for evaluating pituitary adenomas at 3 Tesla

Purpose

To assess the usefulness of contrast-enhanced 3D STIR FLAIR imaging for evaluation of pituitary adenomas.

Methods

Patients with pituitary adenomas underwent MR examinations including contrast-enhanced 3D STIR FLAIR and 2D T1-weighted (T1W) imaging. We subjectively compared the two techniques in terms of 10 categories. In addition, images were rated by side-by-side comparisons into three outcomes: 3D STIR FLAIR imaging superior, equal, or 2D T1W imaging superior. Additionally, the added value of 3D STIR FLAIR imaging for adenoma detection over conventional MR imaging was assessed.

Results

Twenty-one patients were included in this study. 3D STIR FLAIR imaging offered significantly better images than 2D T1W imaging in terms of three categories, including overall visualization of the cranial nerves in the cavernous sinus (mean 4.0 vs. 2.8, p < 0.0001), visualization of the optic nerves and chiasm (mean 4.0 vs. 2.6, p < 0.0001), and severity of susceptibility artifacts (mean 0.0 vs. 0.4, p = 0.004). In the side-by-side comparison, 3D STIR FLAIR imaging was judged to be significantly superior to 2D T1W imaging for overall lesion conspicuity (62% vs. 19%, p = 0.049) and border between the adenoma and the pituitary gland (67% vs. 19%, p = 0.031). The addition of 3D STIR FLAIR imaging significantly improved the adenoma detection of conventional MR imaging.

Conclusion

3D STIR FLAIR imaging improved overall lesion conspicuity compared to 2D T1W imaging. We suggest that 3D STIR FLAIR imaging is recommended as a supplemental technique when pituitary adenomas are invisible or equivocal on conventional imaging.

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.

Novel Diagnostic and Treatment Techniques for Neurogenic Thoracic Outlet Syndrome

Neurogenic thoracic outlet syndrome is a challenging condition to diagnose and treat, often precipitated by the triad of repetitive overhead activity, pectoralis minor contracture, and scapular dyskinesia. The resultant protracted scapular posture creates gradual repetitive traction injury of the suprascapular nerve via tethering at the suprascapular notch and decreases the volume of the brachial plexus cords and axillary vessels in the retropectoralis minor space. A stepwise and exhaustive diagnostic protocol is essential to exclude alternate pathologies and confirm the diagnosis of this dynamic pathologic process. Ultrasound-guided injections of local anesthetic or botulinum toxin are a key factor in confirming the diagnosis and prognosticating potential response from surgical release. In patients who fail over 6 months of supervised physical therapy aimed at correcting scapular posture and stretching of the pectoralis minor, arthroscopic surgical release is indicated. We present our diagnostic algorithm and technique for arthroscopic suprascapular neurolysis, pectoralis minor release, brachial plexus neurolysis, and infraclavicular thoracic outlet decompression.

Clinical Significance of Maximum Intensity Projection Method for Diagnostic Imaging of Thoracic Outlet Syndrome

The aim of this study was to use the magnetic resonance imaging maximum-intensity projection (MRI-MIP) method for diagnostic imaging of thoracic outlet syndrome (TOS) and to investigate the stricture ratios of the subclavian artery (SCA), subclavian vein (SCV), and brachial plexus bundle (BP). A total of 113 patients with clinically suspected TOS were evaluated. MRI was performed in a position similar to the Wright test. The stricture was classified into four grades. Then, the stricture ratios of the SCA, SCV, and BP in the sagittal view were calculated by dividing the minimum diameter by the maximum diameter of each structure. Patients were divided into two groups: surgical (n = 22) and conservative (n = 91). Statistical analysis was performed using the Mann-Whitney U test. The stricture level and ratio in the SCV were significantly higher in the surgical group, while the stricture level and the ratio of SCA to BP did not show significant differences between the two groups. The MRI-MIP method may be helpful for both subsidiary and severe diagnoses of TOS.

Modern Treatment of Neurogenic Thoracic Outlet Syndrome: Pathoanatomy, Diagnosis, and Arthroscopic Surgical Technique

Compressive pathology in the supraclavicular and infraclavicular fossae is broadly termed "thoracic outlet syndrome," with the large majority being neurogenic in nature. These are challenging conditions for patients and physicians and require robust knowledge of thoracic outlet anatomy and scapulothoracic kinematics to elucidate neurogenic versus vascular disorders. The combination of repetitive overhead activity and scapular dyskinesia leads to contracture of the scalene muscles, subclavius, and pectoralis minor, creating a chronically distalized and protracted scapular posture. This decreases the volume of the scalene triangle, costoclavicular space, and retropectoralis minor space, with resultant compression of the brachial plexus causing neurogenic thoracic outlet syndrome. This pathologic cascade leading to neurogenic thoracic outlet syndrome is termed pectoralis minor syndrome when primary symptoms localize to the infraclavicular area. Making the correct diagnosis is challenging and requires the combination of complete history, physical examination, advanced imaging, and ultrasound-guided injections. Most patients improve with nonsurgical treatment incorporating pectoralis minor stretching and periscapular and postural retraining. Surgical decompression of the thoracic outlet is reserved for compliant patients who fail nonsurgical management and respond favorably to targeted injections. In addition to prior exclusively open procedures with supraclavicular, infraclavicular, and/or transaxillary approaches, new minimally invasive and targeted endoscopic techniques have been developed over the past decade. They involve the endoscopic release of the pectoralis minor tendon, with additional suprascapular nerve release, brachial plexus neurolysis, and subclavius and interscalene release depending on the preoperative work-up.

Pectoralis minor syndrome - review of pathoanatomy, diagnosis, and management of the primary cause of neurogenic thoracic outlet syndrome

Thoracic outlet syndrome is an umbrella term for compressive pathologies in the supraclavicular and infraclavicular fossae, with the vast majority being neurogenic in nature. These compressive neuropathies, such as pectoralis minor syndrome, can be challenging problems for both patients and physicians. Robust understanding of thoracic outlet anatomy and scapulothoracic biomechanics are necessary to distinguish neurogenic vs. vascular disorders and properly diagnose affected patients. Repetitive overhead activity, particularly when combined with scapular dyskinesia, leads to pectoralis minor shortening, decreased volume of the retropectoralis minor space, and subsequent brachial plexus compression causing neurogenic thoracic outlet syndrome. Combining a thorough history, physical examination, and diagnostic modalities including ultrasound-guided injections are necessary to arrive at the correct diagnosis. Rigorous attention must be paid to rule out alternate etiologies such as peripheral neuropathies, vascular disorders, cervical radiculopathy, and space-occupying lesions. Initial nonoperative treatment with pectoralis minor stretching, as well as periscapular and postural retraining, is successful in the majority of patients. For patients that fail nonoperative management, surgical release of the pectoralis minor may be performed through a variety of approaches. Both open and arthroscopic pectoralis minor release may be performed safely with effective resolution of neurogenic symptoms. When further indicated by the preoperative workup, this can be combined with suprascapular nerve release and brachial plexus neurolysis for complete infraclavicular thoracic outlet decompression.

Concurrent Validity of Digital Vascular Auscultation for the Assessment of Blood Flow Obliteration on the Radial Artery in Healthy Subjects

This study aimed to determine the validity of digital vascular auscultation for the assessment of changes in the radial pulse in healthy subjects, using Doppler sonography as a validated test referent. Sixty-one non-symptomatic subjects (mean age of 52.5 ± 16.1 years) were assigned and evaluated under one of the following conditions: In condition 1, blood flow of the radial artery was not modified; for condition 2, blood flow of the radial artery was modified using a pressure sleeve around the humerus. The radial pulse was then measured three times with each diagnostic tool by three different blinded evaluators. Both instruments demonstrated a high association between the identification of blood flow modifications or not and the assigned condition (p < 0.001). A strong concordance between the two devices when detecting the “changes” or “no changes” in blood flow was demonstrated (k = 0.936, p < 0.001). Stethoscope sensitivity was 95%, and specificity was 99%. In conclusion, digital vascular auscultation seems to be a valid technique to examine blood flow changes of the radial artery in non-symptomatic subjects, and it could be useful for physical therapists when combined with provocative tests for the screening of possible thoracic outlet syndrome in patients.