Entheseal power Doppler ultrasonography: a comparison of psoriatic arthritis and fibromyalgia.

Objective: To compare the power Doppler ultrasonography (PDUS) pictures of peripheral entheses in patients with psoriatic arthritis (PsA) and fibromyalgia (FM).

Methods: Thirty patients with PsA and 30 with FM participating in a study aimed at identifying the clinical features that distinguish the 2 conditions underwent the PDUS assessment of 14 major peripheral entheses. All of the detected entheseal changes were recorded and scored, and the data were statistically analyzed by means of univariate analysis and receiver-operating characteristic curves.

Results: Four hundred twenty entheseal sites were assessed in each group of patients. At least 1 lesion was detected in each of the patients with PsA and in 80% of the patients with FM (p = 0.01), but inflammatory changes were present in respectively 70% and 23% (p = 0.001). A cutoff point of ≥ 3 involved sites had the greatest discriminating power in the patients with PsA, who were the only patients with bony erosions. PDUS signs of plantar fascia enthesopathy and Achilles tendon inflammation were highly specific of PsA.

Conclusion: PDUS assessment of the peripheral entheses distinguishes patients with PsA and patients with FM in terms of the number and distribution of the involved sites, and the presence of inflammatory changes.