Musculoskeletal Imaging for Dermatologists: Techniques in the Diagnosis and Management of Psoriatic Arthritis

Abstract

Psoriatic arthritis is an inflammatory condition affecting up to 30% of patients with psoriasis. Patients may experience irreversible joint damage if not treated early, and diagnostic delays of even 6 months are associated with radiographic progression and impaired function. Therefore, early detection and intervention are of critical importance in patients with psoriatic arthritis. Given that psoriasis often precedes symptoms of psoriatic arthritis, dermatologists are uniquely positioned to identify patients with psoriatic arthritis early in their disease course, before permanent damage has occurred. Several screening tools have been developed to help dermatologists identify patients who may have psoriatic arthritis, but these tools may not capture patients with subclinical disease or quantify the type and severity of the underlying tissue insult, which is often the presenting sign of psoriatic arthritis. In these cases, a combination of clinical assessment and musculoskeletal imaging (e.g., ultrasound) is required. This review summarizes three common musculoskeletal imaging techniques used in the diagnosis and management of patients with psoriatic arthritis: conventional radiography, ultrasound, and magnetic resonance imaging. Further understanding of musculoskeletal imaging will assist dermatologists in making treatment decisions and allow them to have a more active role in the detection of psoriatic arthritis.

Development of a Predictive Model for Screening Patients with Psoriasis at Increased Risk of Psoriatic Arthritis

“…When conducting clinical and imaging examinations for patients with psoriasis, clinicians should pay more attention to these anatomical sites. Additionally, in patients with psoriasis without clinically confirmed arthritis, several subclinical ultrasound abnormalities including joint effusion, joint synovial thickening, joint PD signals, joint osteophytes, entheses hypoechogenicity, and tendon sheath effusion were detected, which is consistent with a number of previous studies showing that subclinical synovitis and enthesopathy exist in patients with psoriasis with no musculoskeletal symptoms and signs [ 21 , 30 – 33 ]. In addition, in this study, we found no statistically significant difference between the PsA and non-PsA groups for nail dystrophy.…”

“…Among all the variables included in the model, hand joint PD signals, which are indicative of active inflammation [ 21 ], had the greatest contribution to the model. Consistent with this conclusion, a few previous studies showed that the inflammation at metacarpophalangeal joints and proximal interphalangeal joints could be commonly detected in early PsA by ultrasound [ 22 ]; another research study concluded that patients with psoriasis in whom hand synovitis was detected had a 55.5% probability of developing PsA within 1 year [ 16 ].…”

MRI Findings in Axial Psoriatic Spondylarthritis

“…In axial disease, the best imaging modality for both inflammatory (bone marrow edema (BME), osteitis) and structural damage, such as erosions or fat deposits, remains MRI investigation [ 52 ]. Nevertheless, MRI has limitations in characterizing bone remodeling, the morphology of syndesmophytes, or appreciating sclerosis [ 15 ], and it is contraindicated in patients with pacemakers or ferromagnetic metal implants [ 16 ].…”

“…Collaboration between dermatologists and rheumatologists is essential, as they have an important role in diagnosing PsA, since psoriasis might precede arthritis by 7–12 years [ 16 ]. Screening patients with psoriasis without initial articular rheumatic features and identifying the early signs is fundamental for preventing irreversible evolution, joint damage, and function loss.…”

“…MRI allows for the assessment of morphological details in axial and peripheral articulations without ionizing radiation. Its main limitations are high costs and the fact that it is a time-consuming procedure [ 16 ].…”