Power Doppler ultrasonography assessment of entheses in spondyloarthropathies: response to therapy of entheseal abnormalities.

OBJECTIVE: To investigate the response to therapy of entheseal abnormalities assessed with power Doppler (PD) ultrasound (US) in spondyloarthropathies (SpA).

METHODS: A total of 327 patients with active SpA who were starting anti-tumor necrosis factor (TNF) therapy were prospectively recruited at 35 Spanish centers. A PDUS examination of 14 peripheral entheses was performed by the same investigator in each center at baseline and at 6 months. The following elementary lesions were assessed at each enthesis (presence/absence): morphologic abnormalities (hypoechogenicity and/or thickening), entheseal calcific deposits, cortical abnormalities (bone erosion and/or proliferation), adjacent bursitis and intraenthesis and perienthesis (tendon body and/or bursa) PD signal. Response to therapy of each elementary lesion was assessed by calculating change in the cumulative presence from baseline to 6 months. Intraobserver reliability of PDUS was evaluated by blindly assessing the stored baseline images 3 months after the real-time examination.

RESULTS: Complete data were obtained on 197 patients who received anti-TNF therapy for 6 months. In 91.4% of the patients there were gray-scale or PD elementary lesions at baseline and at 6 months. Cumulative entheseal morphologic abnormalities, intraenthesis PD, perienthesis PD, and bursitis showed a significant decrease from baseline to 6 months (p < 0.05). There was high intraobserver reliability for all elementary lesions (interclass correlation coefficient > 0.90, p < 0.0005).

CONCLUSION: Entheseal morphologic abnormalities, PD signal, and bursitis were US abnormalities that were responsive to anti-TNF therapy in SpA. PDUS can be a reproducible method for multicenter monitoring of therapeutic response in enthesitis of SpA.