Table 2 Studies found for shear-wave elastography (SWE) in the assessment of injured or pathologic tendons
Authorsyear [reference] | Subjects (symptomatic and asymptomatic; structures assessed) | Study design, comparison modality | Major findings | Diagnostic performance and correlations (including comparison with clinical examination, conventional US and MRI) |
|---|---|---|---|---|
Patellar, Achilles and epicondylar tendons | ||||
Dirrichs et al. 2016 [52] | 112 patients. Achilles tendon, 41 patients: 34 asymptomatic tendons, 48 symptomatic tendons. Patellar tendon, 38 patients: 25 asymptomatic tendons, 51 symptomatic tendons. Epicondylar tendon, 33 patients: 25 asymptomatic tendons, 41 symptomatic tendons. | Prospective cohort study. Comparison with conventional US using clinical examination as reference standard. | Decreased stiffness in symptomatic tendons. Mean elastic modulus/Vs values of symptomatic tendons: 60.3 kPa/4.48 m/s vs. healthy tendons 185 kPa/7.85 m/s (p = 0.0004). | Conventional imaging + SWE: Sv 94.3%, Sp: 69.1%, Ac 84.8%. USE increased the sensitivity of conventional US detecting tendinopathy. USE was strongly correlated with clinical symptoms (ρ = 0.81, p < 0.001). |
Coombes et al. 2018 [53] | 67 participants: 22 patients with Achilles tendinopathy, 17 patients with patellar tendinopathy, 28 healthy controls. | Cross-sectional, case–control study. Comparison with demographic and functional data. | Achilles tendinopathy: decreased stiffness at the distal insertion (p < 0.001). Patellar tendinopathy: increased stiffness in proximal and mid-patellar region (p = 0.005). | Achilles tendinopathy: Vs < 9.7 m/s, Sp: 81%, Sv: 79%. Patellar tendinopathy: Vs > 9.7 m/s, Sp: 82%, Sv: 77%. Lower proximal patellar Vs was correlated with age (r = − 0.368, p = 0.01). Lower Achilles Vs was associated with higher age (r = − 0.49, p < 0.001), greater BMI (r = − 0.53, p < 0.001), greater pain and disability (r = 0.49, p < 0.046) and fewer single leg calf raises before pain onset (r = 0.646, p = 0.001). |
Achilles tendon | ||||
Chen et al. 2013 [54] | 80 volunteers/36 normal tendons. 14 patients/14 ruptured tendons. | Cross-sectional, case–control study. | Lower and heterogeneous elasticity of torn tendons compared to normal ones, including throughout healing in the subacute stage (p = 0.006). Shear modulus of healthy tendons: 291.91 ± 4.38 kPa. Shear modulus of ruptured tendons: 56.48 ± 68.59 kPa. | |
Aubry et al. 2015 [12] | 80 volunteers/160 asymptomatic tendons. 25 patients/30 symptomatic tendons. | Cross-sectional, case–control study. | Symptomatic tendons were softer (p < 0.001). The presence of areas with no signal in the USE images was a sign of tendinous rupture. | Sagittal SWE with tendon in neutral position: Vs < 5.7 m/s for tendinopathy diagnosis, Sv 41.7%, Sp 81.8%. |
Zhang et al. 2016 [55] | 26 volunteers with rupture of the tendon treated surgically. | Prospective cohort study. Comparison to functional scores. | Tendon stiffness had increased over time (p < 0.05). | Positive correlation between functional scores and elasticity (p = 0.0003). |
Patellar tendon | ||||
Zhang et al. 2014 [56] | 20 volunteers/40 asymptomatic tendons. 13 patients with unilateral patellar tendinopathy/26 tendons. | Cross-sectional, case–control study. Comparison to functional scores. | Increased stiffness on tendons with tendinopathy (p < 0.05). | Significant correlation between increased stiffness in the painful tendon and the intensity of pain and degree of dysfunction. |
Rotator cuff tendons | ||||
Lin et al. 2015 [57] | 39 patients with calcifying tendinopathy/39 tendons. | Cross-sectional. | USE allowed predicting of calcifications that benefit from fine needle aspiration (p < 0.001). | |
Rosskopf et al. 2016 [58] | 22 asymptomatic volunteers. 44 patients with symptomatic shoulder due to tear or tendinopathy of the supraspinatus tendon. | Prospective cohort study. Comparison of Vs of the supraspinatus muscle with MRI characterisation (tendon integrity, tendon retraction, fatty muscle infiltration and muscle volume atrophy). | Mean total Vs in tendinopathy of 2.5 ± 0.5 m/s vs. Vs of 3.0 ± 0.5 m/s in asymptomatic shoulders (p < 0.001). Mean total Vs variable according to different grades of tendon retraction (p = 0.05). Vs decreased with higher fat content and increased in the final stage of fatty infiltration. | |
Capalbo et al. 2016 [59] | 17 asymptomatic volleyball players/17 upper trapezius on dominant side. 26 volleyball players with rotator cuff tendinopathy/26 upper trapezius on dominant side. | Cross-sectional, case–control study. Comparison of upper trapezius shear modulus between the two groups. | Upper trapezius shear modulus was higher in athletes with rotator cuff tendinopathy than the asymptomatic athletes (p = 0.002). | |
Hou et al. 2017 [60] | 35 patients: 21 symptomatic shoulder assessments, 55 asymptomatic shoulder assessments with B-mode US and SWE. | Retrospective and prospective cohort study. Comparison with morphologic grade of supraspinatus tendon on conventional US. | Proximal supraspinatus tendon (p = 0.049) and deltoid (p = 0.004) were softer in symptomatic shoulders. | Weak-to-moderate negative correlation between Vs of the deltoid muscle and morphologic grade of supraspinatus tendon on conventional US: proximal tendon: r = − 0.35; p = 0.004; distal tendon: r = − 20.32; p = 0.007. |
Hatta et al. 2017 [61] | 45 cadaveric shoulders: 25 shoulders with intact rotator cuff, 20 shoulders with rotator cuff tear. | Laboratory study. Comparison of the shear modulus with the extensibility of the supraspinatus muscle under 30- and 60-N loads. | Moderately significant positive correlation of SWE stiffness with stiffness of the supraspinatus muscle measured by a mechanical device. Significant correlation between the shear modulus of supraspinatus muscle and the experimentally measured extensibility in specimens with intact and torn rotator cuff tendons (p < 0.001): 30 N: r (intact) = 0.71, r (tear) = 0.77; 60 N: r (intact) = 0.72, r (tear) = 0.78. | |
Kreplin et al. 2017 [62] | 8 patients: 9 shoulders: 5 with full-thickness supraspinatus tendon tear, 2 with partial thickness supraspinatus tendon tear and 1 with tendinosis without tear. | Cross-sectional. Comparison of Vs with T2/T2* mapping (MRI) of the supraspinatus tendon. | Average Vs = 9.4 ± 2.6 m/s. | Significant negative correlation between T2* and Vs (r = − 0.86, p = 0.013). Significant negative correlation between Vs and tear size (r range 0.71–0.77, p range 0.016–0.034). |
Baumer et al. 2018 [63] | 19 asymptomatic subjects. 11 patients with full-thickness rotator cuff tear of the supraspinatus tendon. | Retrospective case–control study. Comparison of Vs between shoulders with rotator cuff tear and healthy, asymptomatic shoulders. Comparison of Vs with age in healthy, asymptomatic shoulders. | Shoulder with supraspinatus tendon tear had lower mean Vs in supraspinatus muscle and tendon under active conditions (~ 30° scapular plane active abduction) than healthy, asymptomatic shoulders: mean Vs = 3.3 ± 0.8 m/s vs. 4.0 ± 0.4 m/s, p = 0.0024. No difference in Vs between supraspinatus muscle and tendon under passive conditions. | Sv ≥ 0.67 and Sp ≥ 0.63 to distinguish between asymptomatic control subjects and patients with a rotator cuff tear. Mean Vs increased significantly with age in the supraspinatus muscle and tendon of healthy, asymptomatic shoulders (p < 0.05, R2 ≥ 0.23). |