The Value Of Real-time Sonoelastography On Achilles Tendon In Patients With Ankylosing Spondylitis

Objective:Real-time sonoelastography(SE) was performed in 30 healthy volunteers(HV)and 30 patients with ankylosing spondylitis(AS) and the results were contrasted. We investigate the efficacy of SE for assessing Achilles tendon abnormalities. Methods:B-mode ultrasound and SE was longitudinally and transversely performed in Achilles tendons of 30 asymptomatic healthy volunteers and patients with AS. Tendon was divided into proximal(musculotendinous junction), middle(2-6 cm above insertion at the calcaneus) and distal(insertion at the calcaneus) segments. B-mode examinations included tendon thicknesses, widths, echotextures, and enthesopathic findings. Ultrasound images were graded into three grades: grade 1, normal-appearing tendon(parallel margins, homogeneous echotexture); grade 2, enlarged tendon(bowed margins, homogeneous echotexture); grade 3, hypoechoic area with or without tendon enlargement. SE images were evaluated by the following experimentally proven color grading system: grade 1, blue(hardest tissue) to green(hard tissue); grade 2, yellow(intermediate tissue); grade 3, red(soft tissue). Results:B-mode recorded the thickness and width of every segment of Achilles tendon, then calculated the thickness and width ratio. No significant differences was observed in proximal segment between the 2 groups(P=0.495), meanwhile patients with AS performed significant differences with HV at distal and middle segment(P<0.001、P=0.001).The number of abnormal cases of each segment detected by B-mode is not statistically significant between the 2 groups( Pdis=0.298 、 Pmid=0.464 、Ppro=0.315),neither in proximal and middle segment between 2 groups examined by SE(Pdis=0.298、 Pmid=0.464、Ppro=0.315).There is significant differences in distal part between 2 groups examined by SE(Pdis=0.001).B-mode and SE were moderately to well correlated with regard to assessing Achilles tendon abnormalities(Κpro =1.000、 Κmid =0.674、Κdis=0.574). Interesting, SE abnormalities were more common in the middle third of the Achilles tendon in the HV group and in the distal third of the Achilles tendon in the AS group. Conclusions:SE and B-mode were moderately to well correlated with regard to assessing Achilles tendon abnormalities and SE has superior sensitivity in assessing Achilles lesions compared with B-mode. SE may be a new valuable method for detecting AS activity or treatment effect and assessing other inflammatory rheumatic disorders.