Introduction to Rheumatic and Musculoskeletal Diseases (RMDs)

The rheumatic diseases, also called the musculoskeletal disorders, can be characterized by both pain and a subsequent reduction in the range of both motion and function in various areas of the musculoskeletal system; in certain diseases, there are several signs of inflammation which include swelling, redness, and warmth in the affected areas. The immune system attacks the joints, muscles, bones, and organs in rheumatic disorders, which are autoimmune and inflammatory diseases. Rheumatic disorders are sometimes lumped together under the umbrella term “arthritis,” which encompasses over 100 diseases and symptoms. The conditions commonly affect the joints, tendons, ligaments, bones, even muscles, and related organs in certain cases.

There are about 200 different types of rheumatic and musculoskeletal diseases (RMDs) that affect both children as well as adults. The group of diseases is usually caused owing to a compromised immune system or by inflammation, infections, and gradual deterioration caused in the joints, muscles, and bones. Many rheumatic and musculoskeletal diseases are chronic and tend to worsen over time, and they are painful and limit functioning. In severe cases, these disorders can result in a significant disability, deeply impacting the quality of life and life expectancy.

Major Types of Musculoskeletal Disorders:

Chronic Musculoskeletal Pain

Chronic musculoskeletal pain (CMP) is classified as a musculoskeletal pain condition with no identifiable underlying, serious, or specific disorder and is not resolved in less than 3–6 months.

Connective tissue disease

Connective tissue diseases comprise a group of conditions that are characterized by multi-organ inflammation and autoimmunity. The condition is generally uncommon, but when active acutely, it can be life-threatening and might require immediate access to a healthcare provider to prevent multi-system damage.

Juvenile Idiopathic Arthritis

The condition involves inflammation, pain, and swelling in one or more joints for at least 6 weeks. It is often referred to as juvenile arthritis. For instance, according to Versus Arthritis (2018), in 2018, over 12,000 children in the UK suffered from the condition under the age of 16 years.

The most common forms of juvenile idiopathic arthritis comprise oligoarticular JIA, polyarticular JIA, and systemic-onset JIA.

Osteoarthritis

It is the most common form of arthritis and refers to a clinical syndrome of joint pain that is accompanied by several degrees of functional limitation and reduced quality of life. The knee, hip, and joint regions are frequently affected.

Osteoporotic Fracture

Osteoporosis is a condition characterized by reduced bone mass density and deterioration of bone tissue which results in increased bone fragility and susceptibility to fracture. The most substantial single risk factor for osteoporotic fracture is falling and not osteoporosis, and the incidence of bone fracture is increased as bones become weak due to hormonal changes.

Psoriatic Arthritis

Inflammatory arthritis conditions cause inflammation in the joints, and symptoms can include severe pain, stiffness, fatigue, deformity, and reduced joint function. Joints and organs can be affected, and severe inflammatory arthritis can significantly shorten life expectancy.

Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a chronic, progressive and disabling disease where the immune system attacks the synovial lining of the joints and other organs. If left untreated, the joint can lose its shape and alignment, cause bone erosion and ultimately lead to the destruction of the joint and permanent disability. It typically affects the small joints of the hands and the feet, and usually both sides equally in a symmetrical distribution, though any synovial joint can be affected.

Soft Tissue Rheumatism (STR)

Soft tissue rheumatism is a condition affecting tissue surrounding a joint, such as ligaments and tendons, and includes conditions such as tendonitis, bursitis, fasciitis, and fibromyalgia. STR forms a broad spectrum of health problems, most of them poorly defined according to diagnostic criteria and case definitions.

Patient Burden Statistics of Musculoskeletal Disorders

The latest estimates from The Health and Safety Executive (HSE, 2021) indicate the following:

• The total number of work-related musculoskeletal disorder cases in the United Kingdom from 2020 to 2021 was 470,000 (28%), with a prevalence rate of 1,420 per 100,000 workers.. It comprised about 2,12,000 cases in the UK wherein the upper limbs or the neck area was affected; about 1,82,000 where the back was severely affected, and about 76,000 cases where the lower limbs were deeply affected.
• Before the coronavirus pandemic, the rate of self-reported work-related musculoskeletal disorders had shown a generally downward trend. In 2020/2021, the rate was broadly similar to that of the 2018/2019 pre-coronavirus levels
• The number of new musculoskeletal disorder cases was observed to be 162,000, with an incidence rate of about 490 per 100,000 workers.
• Work-related musculoskeletal disorders in Great Britain, by age and gender per 100,000 workers averaged for 2018/19–2020/21 (HSE, 2021).

Musculoskeletal Imaging Tools and Techniques

Musculoskeletal imaging is a sub-specialty of radiology. The imaging of the body’s bones, cartilage, connective tissue, joints, ligaments, muscles, and tendons are referred to as musculoskeletal imaging, which involves the interpretation of the medical images of bones, joints, and associated soft tissues and diagnosis of injuries and diseases. No such modality is expected to be the all-in-one device for musculoskeletal diagnosis. Rather, every modality is a specific tool in a toolbox that performs specific functions and helps solve specific diagnostic problems. For instance, while radiographs or “X-ray films” are useful as a screening tool for the appendicular (extremity fractures), magnetic resonance imaging or MRI will be more useful in diagnosing meniscal tears in the knee region. They can be readily used in various combinations, and thereby, the different modalities can be used in the diagnosis and in characterizing a wide range of musculoskeletal pathology. Musculoskeletal imaging concentrates on the skeleton, ligaments, muscles, and joints by using CT, MRI, X-ray, and ultrasound.

The imaging modalities which are used for the diagnosis of musculoskeletal disorders comprise the following:

X-Ray

Musculoskeletal injuries are challenging to diagnose with a traditional X-ray because it only reveals the static image of a single moment in time. A better X-ray version that can be readily used in diagnosing and treating musculoskeletal conditions involves dynamic digital radiology (DDR). It is an enhanced version of the standard digital radiographic system, which can acquire up to about 15 sequential radiographs per second, resulting in about 20 seconds of both motion and multiple individual radiographic images. It tends to readily improve on the traditional X-ray by capturing a series of individual digital images at a lower dose and higher speed.

The DDR system can perform all the standard X-rays; thereby, the images can be taken with the patient standing, seated, or on the table.

The radiation of a typical DDR is equivalent to two standard X-rays. X-Rays comprise high-energy photons transmitted through a patient at a specific angle (the view) toward a cassette comprising the photographic film. The X-Rays lead to the darkening of the film. The relative density of the structures which are imaged tends to modulate the number of photons that have reached the film, and the dark areas on the completed radiograph also indicate the areas of low density (such as air), and the lighter areas tend to indicate a high-density structure (such as bone). They are not very great at visualizing the soft tissues as they appear in the form of shades of grey, which are difficult to analyze.

Advantages of X-rays

• X-rays are not only inexpensive but they are widely used to provide an excellent initial evaluation of the bone detail and anatomic relationships. They can be considered the most specific type of imaging modality.

Disadvantages of X-Rays

• X-rays are not very sensitive: they are less sensitive to bone marrow pathology than bone scans or MRI and are comparatively less sensitive to cortical bone pathology than the CT scans.
• X-rays are not optimal for the evaluation of the soft tissues. Certain X-ray views (for instance, the pelvis, lumbar, and the spine) lead to a relatively large radiation exposure amongst the patients.
• The associated use of contrast agents along with X-Rays leads to additional risk, including allergic reactions.

Ultrasounds

Ultrasounds are safe and painless equipment that uses sound waves for analyzing different parts of the human anatomy. The technology tends to work on a principle that is similar to that of the sonar that will, in turn, help the submarines in navigation and echolocation. Ultrasounds have several applications, from diagnosing injuries such as muscle tears and chronic conditions, comprising rheumatoid arthritis, tendonitis, carpal tunnel syndrome, bursitis, rotator cuff tears, and joint problems to guiding caregivers through diagnostic and therapeutic procedures. The technique allows the physician to visualize a person’s muscles, tendons, ligaments, nerves, and joints in high resolution.

A hand-held scanning device known as a transducer during a musculoskeletal ultrasound is usually pressed onto the skin. The transducer sends out inaudible and high-pitched sound waves, which tend to travel across the whole body. Also, the denser substances such as the bone reflect the waves while the liquid, including water, tends to allow the waves to pass through. The transducer converts the wave activity into accurate pictures of muscles, tendons, and other structures.

Advantages of Ultrasounds

The use of ultrasounds in diagnosing and managing musculoskeletal diseases has several advantages:

• The ultrasound technique is less expensive than other imaging techniques, such as computed tomography (CT) and magnetic resonance imaging (MRI). It does not expose the patients to any kind of ionizing radiations and does not require contrast for the imaging of inflammation, thereby avoiding potential problems with the contrast-induced allergic reactions, contrast-induced nephropathy, and in the case of gadolinium (on patients with renal insufficiency), nephrogenic systemic fibrosis.
• The musculoskeletal ultrasound is a bedside procedure that allows the clinician to clinically evaluate the patient and perform the diagnostic test at the point of care.
• It also helps in effectively diminishing the time between the initial evaluation, diagnostic imaging, and the initiation of the directed treatment.

Disadvantages of Ultrasound

• The ultrasound system is considered to be an operator-dependent technology comprising poor repeatability.
• Despite the advancements in the resolution of the transducers, the deeper structures are difficult to visualize as the higher-frequency transducers have a much lower tissue penetration.
• The restricted access in terms of visualizing certain joints such as the 4th metacarpophalangeal (MCP) that are difficult to image using an ultrasound probe system is also a disadvantage.

Computed Tomography (CT)

A computed tomography scan is used in the scanning of joints and the spine, thereby helping produce high-resolution images. The high-resolution CT scan of the chest, also known as the HRCT Thorax, is helpful in patients that tend to develop chest complications from chronic rheumatological disorders. Also, the 3D CT scan is beneficial as a preoperative investigation for those patients that require surgery. The cross-sectional imaging techniques that include computed tomography and the PET will more specifically determine conditions such as pneumonitis, dissection, pulmonary embolism, coronary arterial disease, etc., that will not be easily assessed in the case of chest radiographs. Although both the chest X-Rays and CT scans are used to evaluate the initial thoracic manifestations, the high-resolution computed tomography is widely preferred to more accurately analyze the spatial extent of the disease.

High-resolution peripheral quantitative computed tomography (HR-pQCT) is a 3-dimensional imaging modality comprising superior sensitivity for bone changes and abnormalities. The high-resolution peripheral quantitative tomography is used increasingly in inflammatory arthritis to detect the quantitative volumetric measures of bone density, microstructures, local anabolic (such as osteophytes and enthesophytes), and catabolic (such as erosions) bone changes, and the joint space width. The features might be used for monitoring the disease progression in response to therapy and are responsive to differentiating between those with inflammatory arthritis conditions and healthy controls.

Advantages of CT

• Along with the combination of advancements in both image processing and image registration, individual changes can be easily tracked with higher sensitivity and reliability.
• Like MRI, the CT can offer 3D imaging of a joint when compared with the traditional 2D imaging provided by X-Rays.
• CT has several advantages as they are cheaper and have much faster scan acquisition times.      
• When the CT is used in imaging the peripheral joints such as the hand or the knee, the radiation dose is much lower than the background annual radiation dose.
• It has a role in confirming the diagnosis of the osteoarthritis of the hip if the clinical picture or the X-ray is non-diagnostic, specifically as the inferoposterior and the posterolateral hip joint will frequently demonstrate the osteophytes and the loss of joint space, and the region is not visualized on a standard X-ray.

Disadvantages of CT

• Limited availability of scanners
• Lesser resolution of the device, along with the lessened field of view
• Versatility in the measurement of tissues other than bones

Magnetic Resonance Imaging (MRI)

Magnetic resonance imaging (MRI) is frequently used in providing a specific diagnosis of the early course of the rheumatological disease when clinical examination findings might be vague, the radiographs are normal, and the laboratory values seem to be inconclusive. The high contrast and the spatial resolution of the MRI tend to allow detailed evaluation of the bone marrow, articular cartilage, and the periarticular soft tissues. They are highly specific and sensitive in the detection of the common findings of active inflammation in rheumatological diseases, comprising bone marrow edema (BMO), joint effusions, and synovitis, as well as the associated chronic structural lesions, including bone erosions, enthesitis, and cartilage damage in the appendicular skeleton, as well as enthesitis, sacroiliac joint inflammation, and vertebral body involvement of the axial skeleton.

MRI allows the visualization of the bone and the soft tissues in three dimensions as it employs the multiplanar tomography and therefore tends to offer a much better definition of the bony detail than the plain radiography in complex regions such as the carpus.

Advantages of MRI

• The MRI has a clear advantage over other imaging modalities, comprising the plain X-ray imaging and the CT, in the ability to image the soft tissues and fluid within the joint. It involves using contrast agents such as gadolinium, a heavy metal that exerts a paramagnetic effect on the nearby water protons, thereby causing them to relax more rapidly on the T1‐weighted sequences. The signal intensity increases proportionately to the Gd‐DTPA, which distributes rapidly to vascular tissues. Therefore, the highly vascular inflamed synovium will enhance brightly.
• Unlike the X-rays, wherein the individual is exposed to the radiation waves, an MRI does not omit the ionizing radiation waves, thereby protecting an individual from risk. There are a lot of grave consequences that arise after being exposed to the ionizing radiation, and it includes nausea and vomiting, and burns reaching deep within the body tissues, among others.
• The MRI devices are noninvasive. It will thus allow the patients to relax throughout the MRI process.
• A major benefit of the MRI device is that it can be readily used to take pictures of multiple sections of the body at once.

Disadvantages of MRI

• MRI scans are much more expensive than CT scans to diagnose musculoskeletal disorders.
• The MRI scans tend to significantly take a longer time to acquire than the CT, thereby making patient comfort an issue.
• The MR image acquisition is noisy in contradiction to CT.
• MRI scans are not safe for patients that comprise metal implants and foreign bodies.

PET-CT and PET-MRI

PET-CT scanners have been in clinical medicine use since the early 2000s and allow the combination of molecular information from the PET with a high-resolution CT. PET-CT offers detailed images of the bone and the associated molecular information that can be useful in musculoskeletal disorders. The radiotracer tends to provide information on glucose and bone metabolism, and the CT helps to provide the anatomic localization and the detailed bony structures.

The PET-MRI systems have also been introduced recently and attempt to combine the advantages that all the single imaging modalities will allow the musculoskeletal imaging, much like the PET-CT scanners. The PET-MRI tends to utilize much lower radiation doses in contrast to the PET-CT since the CT exposure parameter is removed, which is important when considering how the modalities can be applied to the patient populations. Moreover, MRI is a favorable modality when it is compared to the CT for numerous musculoskeletal disorders because of the superior soft-tissue contrast of the MRI and how prominent the soft tissues are in the case of musculoskeletal disorders.

Advantages of PET-CT/MRI

• The PET-CT/PET-MRI scanning devices are non-invasive, painless, and take about 30 min.
• The devices provide better imaging data and notably increase patient comfort and patient convenience after reducing the number of scanning sessions that a patient must undergo.
• Furthermore, the primary advantage of the PET-CT scan is its ability to correlate findings from two concurrent imaging modalities in a comprehensive examination that combines anatomic data with functional and metabolic information.

Disadvantages of PET-CT/MRI

• The PET-CT/PET-MRI scans can sometimes show areas of high activity that might be mistaken for cancers. Inflammatory conditions such as rheumatoid arthritis or tuberculosis tend to absorb a lot of tracers, thereby generating confusing results.
• It generates less accurate results in various situations comprising slow-growing, less active tumors which might not absorb much tracer.
• Certain small tumors (less than 7mm) might not be detectable.

Recent Developments Associated With the Musculoskeletal Imaging Devices

• On April 28, 2022, the Nano-X-Imaging Ltd., an innovative medical imaging technology company, received the US FDA clearance for the HealthOST device, an AI software that provides qualitative and quantitative analysis of the spine from CT to support clinicians in the evaluation and assessment of musculoskeletal disease.
• On February 10, 2022, Esaote North America Inc. announced the US FDA approval of the Magnifico Open MRI, a new open whole-body MRI system that is commercialized in the United States.
• On October 06, 2021, Wipro and GE Healthcare inaugurated the first digital PET MR, also known as SIGNA™ PET/MR 2.0, in India. It is powered by the simultaneous image acquisition from GE’s latest 3.0 Tesla MR Technology and PET technology.
• On October 01, 2021, the US FDA approved the Siemen’s Naeotom Alpha Device, which uses the photon-counting detectors to measure every X-ray that passes through the patient’s body that can provide more useful information to the clinicians than the detectors which measure the total energy in several X-Ray units at once.
• On November 08, 2021, the digital X-Ray Company, Nanox, completed its merger with the Zebra Medical Vision, which is now rebranded as the Nanox.AI, for approximately USD 110 million in the stock, along with an ability to earn an additional USD 84 million in stock.
• On September 01, 2021, GE Healthcare introduced the AMX Navigate, a new portable, digital X-Ray system designed with a first-of-its-kind power-assisted free-motion telescoping column that aims to cause a reduction of the lift force by up to 70% and a decrease in the technologist injury.
• On August 19, 2021, the EchonOus point of care was approved by the Food and Drug Administration for an ultrasound platform for the full-body probe.
• On November 29, 2019, EOS Imaging received the US FDA 510 (k) clearance for the EOSedge, its new generation innovative imaging system.

Competitive Assessment of MSK Imaging Devices

Analyst’s Perspective on the Musculoskeletal Imaging Devices Market

Early diagnosis is a key to successful analysis and treatment across the globe for most chronic disorders. Due to the increasing awareness of the early-stage diagnosis, the demand for diagnostic imaging is expected to grow higher in volume across the X-Ray, CT, and MRI modalities. With the rise observed in the aging demographics, there will be a higher demand for disease diagnosis; as people age, they become more susceptible to disease and disability, which will drive the diagnostic imaging services. Additionally, there will be an enhanced role of Artificial Intelligence (AI) in the medical image diagnosis by the aiding radiologists to spot anomalies in the human tissues, improvising a patient experience that will include the use of bedside imaging and the rise in-home care and diagnosis and the growth of the diagnostic wearable devices. The demand for both values, mid-tier and premium offerings of musculoskeletal imaging devices is spiraling to meet the fundamental layered nature of the global market. The industry continually evolves by introducing affordable product solutions and technological advancements worldwide, allowing clinicians to solve complex problems.

Furthermore, the rising awareness regarding musculoskeletal disorders in people is one of the key driving factors that is expected to boost the global musculoskeletal imaging system market growth. Moreover, the increasing prevalence of musculoskeletal disorders due to the rising incidence of rheumatoid arthritis, sarcopenia, osteoporosis, and psoriatic arthritis is expected to cause a surge in the growing demand for musculoskeletal imaging devices, which will ultimately drive the market growth. An increase in the demand for X-rays in the healthcare industry will increase the diagnosis of musculoskeletal diseases among individuals, thereby impacting the musculoskeletal imaging system market positively. Certain technologies such as musculoskeletal ultrasound will continue to evolve further into a tool for minimally invasive surgeries. The current advancements in the field of musculoskeletal ultrasound will also bring an era of ultrasound-guided surgery. Also, the arthroscopic surgery might be superseded by ultrasound-guided surgery, allowing the musculoskeletal ultrasound to perform more minimally invasive therapeutic procedures.

Conclusion

The emergence of musculoskeletal imaging techniques earlier was essentially in the form of plain X-rays. However, it possessed several limitations in the visualization of many soft-tissue pathologies. After that, the introduction of ultrasound as a diagnostic tool marked the beginning of the ultimate age of non-radiation investigation. The newer forms of diagnostic imaging modalities that comprised computed tomography (CT) and magnetic resonance imaging (MRI) were invented consequently, thereby allowing the delineation of multidirectional and high-resolution information regarding various other pathological conditions. Today, musculoskeletal imaging devices have become an indispensable diagnostic imaging modality in various clinical settings. The evaluation and the characterization of the skeletal muscles pathology are found to be a more frequently encountered indication of musculoskeletal imaging. The causes of the muscular pathology are found to be versatile and comprise traumatic, autoimmune, infectious, inflammatory, neurologic, and neoplastic. Every etiology that was dramatically different in pathophysiology might be present with several imaging features. The understanding of the subtle differences in the imaging features between the pathologic conditions will allow for both the guidance of diagnosis and treatment of MSK disorders.