Role of Shear-Wave Elastography in Achilles Tendon in Psoriatic Arthritis and Its Correlation with Disease Severity Score, Psoriasis Area and Severity Index

Purpose The aim of this study was to compare accuracy of shear-wave elastography (SWE) with gray scale (GS) ultrasound and power Doppler (pD) for diagnosing Achilles tendinopathy in psoriatic patients with and without arthritis and correlation with achillodynia and disease severity score, psoriasis area and severity index (PASI). Methods A total of 100 Achilles tendons were evaluated where 56% were cases of psoriatic arthritis with achillodynia; 44% were controls of psoriasis without arthritis in this prospective study. Evaluation was done with GS, pD, SWE at proximal, mid, and distal third of the tendon. Qualitative (color maps) and quantitative data, elastic modulus, kilopascal (kPa), were generated. Pearson's correlation was done to see association between kPa, PASI and clinical symptoms, achillodynia, scored using visual analog scale (VAS). Results Significant negative correlation was seen between duration of arthritis, VAS and PASI with SWE values with r = -0.34, -0.47, and -0.41, respectively. SWE could identify abnormal tendons in 71/100 (71%) in the overall study, 53/56 (94.6%) in cases, and 18/44 (40.9%) in control. The statistical significance was set at p <= 0.05. In comparison, conventional ultrasound, GS, and pD together could identify 13/56 (23.21%) in cases and no abnormal tendon was identified in the control group. Conclusion SWE is a reliable, noninvasive, and valuable tool to detect early tendinopathy and monitor progression of disease.