Enthesitis in psoriatic arthritis (Part 2): imaging

Area of Science:

• Rheumatology and Musculoskeletal Imaging

Background:

• Enthesitis is a key feature of psoriatic arthritis (PsA), potentially preceding synovitis.
• Clinical assessment of enthesitis lacks structural detail, sensitivity, and specificity.
• Soft tissue imaging offers superior visualization of entheseal changes compared to clinical exams.

Purpose of the Study:

• To review contemporary concepts of entheses in imaging.
• To discuss confounders in assessing entheseal alterations.
• To evaluate the role and limitations of imaging techniques in PsA.

Main Methods:

• Review of musculoskeletal ultrasound (MSKUS) and magnetic resonance imaging (MRI) for enthesitis.
• Discussion of Doppler ultrasound for vascularity assessment.
• Consideration of biomechanical factors and development of imaging entheseal indices.

Main Results:

• MSKUS provides high-fidelity imaging of superficial entheses and vascularity but not bone.
• MRI visualizes bone marrow and soft tissue edema but struggles with entheseal structure differentiation.
• Biomechanical factors like body weight can confound imaging assessments.

Conclusions:

• Ultrasound and MRI are complementary tools for evaluating enthesitis in PsA.
• Awareness of imaging limitations and biomechanical confounders is crucial for accurate assessment.
• Further development of imaging indices is needed to refine enthesitis evaluation.