Unusual, but important, peri- and extra-articular manifestations of rheumatoid arthritis: a pictorial essay

Role of Imaging in Nondegenerative Arthritis in Low- and Middle-Income Countries

Arthritis is an important cause of disability globally, with high prevalence in low- and middle-income countries. Although osteoarthritis is the most common type of arthritis, various types of nondegenerative arthritis are prevalent in low- and middle-income countries. Multiple imaging modalities, such as radiography, ultrasound, computed tomography, and magnetic resonance imaging, are helpful in diagnosing and prognosticating arthritis. Although imaging appearances can overlap between types of arthritis, specific imaging findings have been described for the different etiologies. Knowing these imaging findings, especially on radiographs and ultrasound in resource-constrained areas, can be helpful in managing arthritis effectively.

Pivotal role of the synovioentheseal complex in the imaging of arthritis and rheumatic diseases

Imaging plays a key role in the diagnosis and management of rheumatic diseases. Although joints and periarticular tissue are commonly involved in rheumatic diseases, entheses further away from joints, such as in the Achilles tendon or plantar fascia insertion onto the calcaneus, as well as skin and subcutaneous tissue, are among other -sometimes overlooked- targets. The link of enthesitis, which describes inflammation at the insertions of ligaments, tendons, or joint capsules, with spondyloarthritis (SpA) was established just before the turn of the century as a characteristic feature based on imaging studies with histopathological correspondence. To highlight the association between enthesitis and synovitis in SpA, the anatomical unit of the “synovioentheseal complex” (SEC) and the concepts of “functional enthesis” and “articular enthesis,” apart from the better known “insertional enthesis,” were introduced to encompass other inflammatory lesions associated with SpA. Studies from the last two decades revealed the involvement of the SEC in rheumatic and non-rheumatic disorders with different pathogeneses. Although such involvement is sometimes distinctive, it does not necessarily point to a specific diagnosis at other times. Nevertheless, the potential of SEC inflammation in the differentiation of SpA from other forms of arthritis remains important. The purpose of this review was to provide essential information concerning the involvement of the SEC in the diagnosis of rheumatic diseases and arthritis, focusing on imaging characteristics.

Rare Occurrence of Scapulothoracic and Ischiogluteal Bursitis Signifying Poorly Controlled Rheumatoid Arthritis

ABSTRACT

A 74-year-old man with poorly controlled seropositive rheumatoid arthritis was referred for 18F-FDG PET/CT for follow-up of lung cancer, which demonstrated intense FDG activity in atlantoaxial, sternoclavicular, glenohumeral, and hip joints consistent with active rheumatoid arthritis. There was also unexpected intense uptake at scapulothoracic, ischiogluteal, and trochanteric bursae signifying active bursitis.

A problem-based approach in musculoskeletal ultrasonography: central metatarsalgia

Ultrasonography (US) is a useful diagnostic method that can be easily applied to identify the cause of metatarsalgia. The superficial location of structures in the foot, dynamic capability of US, and the ability to perform direct real-time evaluations of the pain site are also strong advantages of US as a modality for examining the foot. Moreover, knowing the possible pain sources to investigate when a patient has a specific site of pain will enhance the diagnostic quality of US, and will help radiologists to perform US efficiently and effectively. The purpose of this article is to review the common etiologies of metatarsalgia including Morton’s neuroma, plantar plate injury, synovitis, tenosynovitis, bursitis, and metatarsal fractures, and to discuss their US features.