Imaging features and diagnosis of early psoriatic arthritis with lower limb entheseal abnormalities in psoriasis patients under high frequency ultrasonography

Psoriatic arthritis (PsA) is a musculoskeletal inflammatory disease, which is always derived from psoriasis. Among psoriasis patients, about 3-8% display several similar articular symptoms with early psoriatic arthritis (ePsA). Studies have shown that ultrasound performs remarkably well in checking the effusion, soft tissue inflammation, tendon injury, etc. It is also reported that high frequency ultrasound can be used to differentially diagnose PsA and rheumatoid arthritis (RA) by examining finger joint soft tissue lesions. Thus, ultrasound is thought to be effective for the early diagnosis of PsA and the differential diagnosis of ePsA and psoriasis. However, this hypothesis remains unclear and unexplored. In our experiments, to investigate lower limb entheseal abnormalities in patients with early psoriatic arthritis (ePsA) and psoriasis, sixty patients with ePsA, one hundred patients with psoriasis and twenty healthy controls were divided into groups. High frequency ultrasound was performed to examine the entheses (quadriceps, patellar, Achilles tendons and plantar fascia) of the lower limbs and the Glasgow Ultrasound Enthesitis Scoring System (GUESS) scores and a clinical assessment were conducted. The results showed that the mean GUESS scores were significantly higher in patients with ePsA (7.8 +/- 1.7) and psoriasis (7.4 +/- 0.9) compared to the controls (2.4 +/- 0.4) (P<0.01). The enthesophytes and bursitis of the Achilles tendon and the bony erosions and the PD signal of the ePsA group were higher than the psoriasis group (P<0.05). The GUESS scores did not correlate with the psoriasis course, morning stiffness, the Psoriasis Area and Severity Index (PSAI), the Maastricht Ankylosing Spondylitis Enthesitis Index (MASES) or the Health Assessment Questionnaire modified for SpA (SHAQ). In conclusion, entheseal abnormalities are common in patients with psoriasis and ePsA. Regular screening of patients with psoriasis via high frequency ultrasound can help to detect ePsA.