The association of achilles sonoelastography findings with disease activity, functional status and enthesitis index in patients with axial spondyloarthritis

Abstract

Background Sonoelastography (SE) is a new ultrasound (US)-based technique able to assess tissue elasticity. Using conventional US, it is sometimes difficult or even impossible to distinguish pathologic tissue because it often presents with the same echogenicity as the surrounding healthy tissue. This study aimed to evaluate SE findings in Achilles tendons of patients with axial spondyloarthritis (axSpA) and to assess how these findings are associated with disease-related parameters.

Material and Methods Sixty-four consecutive patients (37 men, 27 women; mean age 39.7 years; range 20-65 years) with axSpA and 30 sex and age-matched healthy controls were enrolled in the study. Disease activity was evaluated using the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), whereas functional capacity was evaluated using the Bath Ankylosing Spondylitis Functional Index (BASFI). Erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) and the Spondyloarthritis Research Consortium of Canada (SPARCC) enthesitis index were recorded. All participants underwent an SE examination of the Achilles tendon and measurement of the strain index (SI).

Results The mean right and left SI were significantly higher in axSpA patients than in controls (2.96 +/- 0.94 vs. 1.90 +/- 0.45; p<0.001; 2.95 +/- 0.95 vs. 1.92 +/- 0.48, p<0.001, respectively). In axSpA patients, both right and left SI were significantly correlated with the BASDAI, BASFI and SPARCC enthesitis indices, but not with ESR or CRP.

Conclusion AxSpA patients had an increased SI compared with healthy subjects and these values were associated with disease activity, functional capacity and the enthesitis index. SE may be a useful tool for the evaluation of Achilles tendons in patients with axSpA.