Diagnosing Thoracic Outlet Syndrome (TOS) can be challenging because symptoms such as arm pain, numbness, tingling, weakness, swelling, and discoloration can overlap with many other conditions.

Many patients ask, “what is the best test for Thoracic Outlet Syndrome?”

No single test replaces evaluation by an experienced TOS specialist. However, specialized imaging provides critical information about the anatomy of the thoracic outlet and proves compression or tension involving the brachial plexus, subclavian artery, subclavian vein, muscles, ribs, and surrounding structures. This information is critical in the hands of a TOS specialist.

NeoVista® MRI is a Unique and highly specialized MRI examination developed specifically for patients with the suspected or confirmed clinical diagnosis of Thoracic Outlet Syndrome. Unlike a standard MRI, NeoVista® clearly demonstrates the multiple anatomical and dynamic factors that can cause TOS.

What Is Thoracic Outlet Syndrome?

The thoracic outlet is the highly complex space on each side between the base of the neck, the upper chest, and the shoulder. You can feel your own thoracic outlet on each side by placing your fingers just behind your collar bone. There are multiple tunnels in each thoracic outlet through which pass critical nerves and blood vessels. When there is symptomatic compression or stretching of these nerves or vessels, thoracic outlet syndrome is present.

Three basic types of thoracic outlet syndrome (TOS) have been classically defined:

• Neurogenic Thoracic Outlet Syndrome (nTOS) – compression or stretching of the nerves of the brachial plexus.
• Venous Thoracic Outlet Syndrome (vTOS) – compression and damage to the subclavian vein, with blood clots.
• Arterial Thoracic Outlet Syndrome (aTOS) – compression and damage to the subclavian artery, with aneurysm, stricture, and possible blood clots.

Neurogenic TOS makes up 90 to 95% of all cases of TOS and unfortunately remains the most difficult type to diagnose. In addition, more than one type of TOS may occur in the same patient at the same time.

Determining what is being compressed—and why—is critically important because different anatomical problems can require very different treatment strategies.

How Is Thoracic Outlet Syndrome Diagnosed?

A doctor typically begins the investigation for TOS with a detailed medical history and physical examination.

The diagnostic process may include:

• Physical examination
• Provocative maneuvers
• X-rays
• Ultrasound
• CT or CT angiography
• MRI
• MR angiography or venography
• Electrodiagnostic testing (EMG and NCV) in selected patients
• Specialized TOS imaging

Each test provides information about a different element of TOS. The standard neurologic examination is almost always negative in TOS patients, requiring an experienced TOS specialist to perform unique TOS provocative maneuvers. Unfortunately, these provocative tests range in accuracy between 30% and 50% and are not specific. The contribution of dedicated TOS imaging is, therefore, incredibly valuable in these patients. Imaging results are typically combined with the clinical findings above to produce the highest accuracy in diagnosis of TOS.

Why Can Thoracic Outlet Syndrome Be Difficult to Diagnose?

The diagnosis of Neurogenic TOS remains extremely challenging due to several factors:

• The thoracic outlet defines a series of confined tunnels in a highly complex anatomic area of the body.
• The thoracic outlet in each person is unique, with many known variants of the muscles, nerves and bones.
• The size and shape of the tunnels of each thoracic outlet change with arm motion.
• Different parts of the brachial plexus are involved in different patients.
• Symptoms frequently occur in certain arm positions but not in others.
• Symptoms may overlap with other conditions such as cervical spine disease or shoulder disease.

A standard neurologic examination is often unremarkable, while provocative TOS tests involving arm motion can elicit symptoms that are not otherwise present. Arm position matters.

What Is a Thoracic Outlet Syndrome MRI?

A Thoracic Outlet Syndrome MRI uses magnetic resonance imaging to visualize structures within and surrounding the thoracic outlet.

MRI is particularly useful for evaluating soft tissues.

Depending on the imaging protocol, MRI may help visualize:

• Brachial plexus
• Scalene muscles
• Subclavian arteries
• Subclavian veins
• Fibrous bands
• Clavicle
• First ribs
• Cervical ribs
• Cervical spine
• Upper thoracic spine
• Other surrounding structures

Unlike CT and X-ray examinations, MRI does not use ionizing radiation.

Can a Standard MRI Diagnose Thoracic Outlet Syndrome?

Many clinical TOS doctors turn to their radiology colleagues to request imaging for Thoracic Outlet Syndrome. In most cases, the radiologist will recommend a standard MRI of the brachial plexus. We have seen many of these images and accompanying reports, and they almost never find the critical structures causing the symptoms. These traditional MRI protocols may be excellent for evaluating a particular body region but they fall short when investigating the complex combination of nerve, vascular, muscular, skeletal, and positional abnormalities associated with TOS. The NeoVista® MRI has been designed to overcome these limitations.

What Is NeoVista® MRI for Thoracic Outlet Syndrome?

The NeoVista® MRI is a specialized MRI examination developed specifically for patients with Thoracic Outlet Syndrome.

The first NeoVista examination was performed in San Francisco in 2004. Since then, thousands of TOS patients and hundreds of physicians have sought out this unique and valuable examination.

Each NeoVista® examination provides a comprehensive evaluation of the structures and dynamic arm changes that cause neurogenic thoracic outlet syndrome:

• Anatomic tunnels of each thoracic outlet
• Brachial plexuses
• Subclavian arteries and their major branches
• Subclavian veins and other relevant veins
• Scalene muscles
• Muscle variations
• Fibrous bands
• Cervical ribs
• First rib abnormalities
• Changes occurring with arm movement
• Shoulder girdle movement
• Cervical spine
• Upper thoracic spine

This allows the patient‘s physician to understand detailed anatomical information that must be considered alongside information from the specialized clinical examination.

How Is NeoVista Different From a Standard MRI?

NeoVista® was specifically developed around the diagnostic challenges associated with Thoracic Outlet Syndrome.

Rather than simply producing static images of one brachial plexus, the examination is designed to investigate multiple potential causes and components of TOS, including nerves, blood vessels, critical anatomic structures, cervical spine, and arm motion.

One particularly important distinction is the demonstration and measurement of arm motion.

Compression or tension of the nerves and blood vessels frequently changes as the arms move. NeoVista® demonstrates these changes, and we perform our proprietary measurement system on the critical bones of the shoulder and neck. This is critical information is not available in any standard MRI of the brachial plexus.

Dr. Scott Werden, the leading figure in this field, interprets every NeoVista® MRI examination. Dr. Werden has interpreted thousands of these studies.

What Can a TOS MRI Show?

The NeoVista® Thoracic Outlet Syndrome MRI identifies normal anatomy and abnormal findings:

Brachial Plexus Compression

The brachial plexus is the network of nerves traveling from the neck into the shoulder and arm.

Compression or tension of these nerves causes a unique pattern of symptoms in patients with neurogenic TOS.

Abnormal Scalene Muscles

Variations or abnormalities involving the scalene muscles cause narrowing or compression within the thoracic outlet.

Fibrous Bands

Fibrous bands are present in some patients with Neurogenic TOS and are difficult to evaluate through physical examination alone

Cervical Ribs or Abnormal First Ribs

Some patients have an extra cervical rib above the first rib, or an abnormal first rib that causes narrowing of the thoracic outlet.

Subclavian Artery Compression

The NeoVista® MRI examination also demonstrates the arteries that pass through each thoracic outlet. It may identify compression, narrowing, an aneurysm, or a blood clot.

Subclavian Vein Compression

The NeoVista® MRI examination can rule out blood clots and assess for compression or abnormality of the subclavian veins in each thoracic outlet.

Changes With Arm Movement

Each NeoVista® MRI examination includes our proprietary method of measuring the positions of the shoulder blades, collar bones, first ribs, and neck, a unique critical service.

MRI vs. Ultrasound for Thoracic Outlet Syndrome

Some TOS specialists utilize ultrasound for limited purposes. Ultrasound can assess real-time blood flow as well as dynamic changes in this blood flow on arm motion. Ultrasound visualizes portions of the brachial plexus, but not as well as MRI. Ultrasound has gradually become more useful over the years as practitioners recognize some of the same brachial plexus abnormalities we see on MRI. Additionally, ultrasound is the best modality for guiding selective muscle blocks and hydrodissection, among other procedures.

However, ultrasound has limitations. Ultrasound does not penetrate bone easily, and the critical costoclavicular interval on each side is obscured. This costoclavicular interval is one of the more common areas where the brachial plexus becomes compressed on arm motion. MRI provides more comprehensive visualization than ultrasound of many soft-tissue structures, including the brachial plexus, muscles, fibrous bands, and surrounding anatomy.

The appropriate choice of test depends on the type of TOS suspected and the clinical questions the physician needs answered.

MRI vs. CT for Thoracic Outlet Syndrome

CT provides excellent visualization of bone and can be particularly useful when evaluating skeletal abnormalities.

CTA (CT angiography) requires the injection of intravenous contrast material. CTA provides detailed information about the arteries and veins as they pass through the thoracic outlet.

However, CT and CT angiography suffer from limitations in patients with neurogenic TOS. CT or CTA requires ionizing radiation. Physicians always try to limit ionizing radiation, especially when other tests are available that provide the same or more information. MRI and ultrasound do not utilize ionizing radiation. CT shows significantly less soft tissue contrast than does MRI, which limits evaluation of the brachial plexus, fibrous bands, and muscles in each thoracic outlet. MRI provides detailed soft-tissue imaging without ionizing radiation.

In a limited number of cases, CT or CT angiography can provide complementary information when used in conjunction with MRI, but should not be a first-line test in patients with the diagnosis of neurogenic TOS.

Why Does Identifying the Cause of TOS Matter?

Two people can suffer from neurogenic thoracic outlet syndrome while having very different underlying anatomical problems.

For example, one patient might suffer from nerve compression symptoms caused by brachial plexus compression due to abnormal scalene muscles, while another patient suffers from brachial plexus and arterial compression caused by a cervical rib.

Those differences matter.

A TOS specialist would quite likely make very different treatment decisions based on these two different scenarios if that information was available.

Treatment decisions like these must be individualized according to the patient’s clinical diagnosis, anatomy, symptoms, and other medical factors.

Detailed imaging can help the treating specialist better understand where compression occurs, what structures are involved, and what anatomical factors may be contributing to it. In this way, the TOS specialist can make the best decision for each patient.

Who Interprets the NeoVista® MRI?

Every NeoVista® MRI examination receives a full and detailed interpretation by Dr. Scott Werden.Dr. Scott Werden achieved board certification in both internal medicine and diagnostic radiology. He has spent the past 25 years studying thoracic outlet syndrome and developing and refining the NeoVista MRI protocol for patients with thoracic outlet syndrome. He is widely regarded throughout the TOS community, both nationally and internationally.

Dr. Werden developed the NeoVista MRI protocol to address limitations he identified in conventional approaches to TOS imaging. His program has continued to evolve through experience with thousands of TOS examinations, collaboration with TOS specialists, surgical correlation, clinical follow-up, and ongoing refinement of the imaging protocol.

For a condition as complex as TOS, both the imaging protocol and the experience of the physician interpreting the examination are vitally important.

Frequently Asked Questions About TOS MRI

What is the best test for Thoracic Outlet Syndrome?

At present, there is no single test that diagnoses neurogenic thoracic outlet syndrome perfectly. Clinical tests, even provocative clinical tests designed for the diagnosis of neurogenic thoracic outlet syndrome, are limited to a maximum of approximately 50% accuracy. Specialized Imaging is critical for understanding the numerous underlying anomalies and causes of neurogenic TOS, and MRI is, in our opinion, the best test for this purpose. Ultrasound has some very useful but limited capabilities, and CT/CT angiography are valuable adjuncts in a limited number of cases. Imaging should always be used in conjunction with the TOS specialist’s clinical examination.

Can MRI detect Thoracic Outlet Syndrome?

MRI can provide detailed images of anatomical abnormalities and compression involving structures associated with TOS. Imaging findings should be interpreted together with the patient’s symptoms, physical examination, and clinical evaluation.

What is the best MRI for Thoracic Outlet Syndrome?

The NeoVista® MRI/MRA/MRV examination was developed specifically for patients with Thoracic Outlet Syndrome. This study evaluates every critical structure of the thoracic outlet, with propietary measurement of arm motion not offered by any other provider. Dr. Scott Werden, who interprets every NeoVista MRI examination, has dedicated himself to diagnosing TOS over several decades and is widely regarded as the go-to expert in this field.

What is NeoVista MRI?

NeoVista® is a specialized MRI examination specifically designed for patients with a clinical diagnosis of Thoracic Outlet Syndrome. The examination combines detailed evaluation of neurological, vascular, musculoskeletal, and dynamic components of the thoracic outlet. The NeoVista MRI examination is available at multiple providers nationwide, and each examination is completed within 45 minutes.

Does NeoVista evaluate neurogenic TOS?

Yes. NeoVista includes detailed evaluation of the brachial plexus and surrounding anatomical structures that may contribute to neurogenic Thoracic Outlet Syndrome.

Can NeoVista evaluate vascular TOS?

NeoVista includes evaluation of the subclavian arteries and veins and demonstrates compression of blood vessels, damage to blood vessels, and blood clots.

Can an MRI show brachial plexus compression?

When performed properly, MRI provides Detail pictures of the brachial plexus and its relationship with surrounding structures. Specialized imaging can also evaluate how those anatomical relationships change with arm position.

Does MRI use radiation?

MRI does not use ionizing radiation. It uses a magnetic field and radiofrequency energy to produce images.

How long does a NeoVista MRI take?

The NeoVista® examination is designed to gather its comprehensive TOS imaging information in approximately 45 minutes.

Who reads a NeoVista MRI?

Every NeoVista® examination is interpreted by Dr. Scott Werden, a diagnostic radiologist specializing in Thoracic Outlet Syndrome imaging.

How many patients have received a NeoVista MRI?

More than 3,000 patients have undergone NeoVista TOS examinations after referrals from more than 300 TOS specialists nationwide, according to TOSMRI.com.

Learn More About Specialized MRI for Thoracic Outlet Syndrome

Most physicians, even experienced TOS specialists, find the diagnosis of Neurogenic Thoracic Outlet Syndrome extremely challenging. The underlying anatomy of the thoracic outlet can differ considerably from one patient to another. Dynamic changes Dementia associated with arm motion are difficult to predict.

Every patient with the potential diagnosis of neurogenic thoracic outlet syndrome should see an experienced TOS specialist. A full clinical evaluation is a critical part of the diagnosis, but after that evaluation, specialized MRI, like the NeoVista® examination, provides critical information that cannot be obtained from the clinical examination alone.

NeoVista® MRI was developed specifically for this purpose: providing comprehensive, specialized imaging for patients with Thoracic Outlet Syndrome.

If you have been diagnosed with TOS or your physician is evaluating you for the condition, talk with your healthcare provider about which imaging tests are appropriate for your individual situation.

TOSMRI.com | NeoVista® MRI for Thoracic Outlet Syndrome

Learn more about specialized TOS imaging, diagnosis, treatment, and Thoracic Outlet Syndrome specialists atTOSMRI.com.