Comparison of diagnostic image modalities for detection of Achilles tendon tendinopathy using ankle magnetic resonance imaging

Joohyun Lee¹Jee Young Lee²Keum Nae Kang³Soyoon Park⁴Jae Ni Jang⁵Sukhee Park⁵YOUNG UK KIM^4*

• ¹Department of Anesthesia and Pain Medicine, CHA Ilsan Medical Center, CHA University, Ilsan, Republic of Korea
• ²Department of Korean Medicine, Integrative Cancer Center, CHA Ilsan Medical Center, CHA University, Ilsan, Republic of Korea
• ³Department of Anesthesiology and Pain Medicine, National Police Hospital, Seoul, Republic of Korea, Seoul, Republic of Korea
• ⁴Department of Internal Medicine, Incheon St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
• ⁵Department of Anesthesia and Pain Medicine, International St. Mary’s Hospital, Incheon, Incheon, Republic of Korea

Background: A thickened AT (Achilles tendon) is one of the important morphological change of tendinopathy of the Achilles tendon (ATTP). Previous researches have demonstrated that the both achilles tendon thickness (ATT) and achilles tendon CSA (ATCSA) is correlated with ATTP in subjects. However, the comparative value of ATT and ATCSA according to ATTP is not clear and no studies have calculated the clinical best threshold values of ATT and ATCSA. The goal of this research was to assess ATT and ATCSA that which parameter is more sensitive to predict ATTP.Methods: AT lesions were enrolled from 31 subjects with ATTP and from 36 asymptomatic subjects who performed ankle-magnetic resonance imaging (A-MRI) and revealed no diagnosis of ATTP. Axial A-MRI T1-weighted images were performed at the AT level. We measured the ATT and ATCSA at the junction of the soleus and gastrocnemius aponeurosis on the A-MRI using an image analysis program. The ATT was measured as the thickest point at the AT margin. The ATCSA was measured as the cross-sectional ligament whole area of the AT that was most inflamed lesions. In addition, a subgroup analysis by sex was performed to evaluate gender-specific diagnostic performance of ATT and ATCSA.The average ATT was 3.83 ± 0.76 mm in the normal group and 5.42 ± 0.97 mm in the ATTP group. The average ATCSA was 46.49 ± 7.12 mm 2 in the normal group and 82.59 ± 29.71 mm 2 in the ATTP group. ATTP subjects had significantly higher ATT (p<0.001) and ATCSA (p<0.001) than the control subjects. A ROC curve analysis showed that the best threshold value of the ATCSA was 57.20 mm2. The responsiveness of ATCSA was 87.1% and its precision was 88.9%. The optimal threshold value of the ATT was 4.64 mm. The responsiveness of ATT was 80.6% and its precision was 80.6%. We compared area-under-the-curve (AUC) for two analyzed diagnostic methods. The ATCSA`s AUC is 0.95 (95% CI, 088-1.00), and the ATT`s AUC is 0.91 (95% CI, 0.84-0.97).Even though the ATCSA and ATT were both significantly correlated with ATTP, the ATCSA was a more sensitive measurement parameter.