Introduction
Compression elastography (CE)
Shear-wave elastography (SWE)
Materials and methods
Results
Authors year [reference] | Subjects (symptomatic and asymptomatic; structures assessed) | Study design, comparison modality | Major findings | Diagnostic performance and correlations (including comparison with clinical examination, functional scores, conventional US and MRI) |
---|---|---|---|---|
Achilles tendon | ||||
De Zordo et al. 2010 [27] | 25 volunteers/50 asymptomatic tendons. 25 patients/25 tendons. | Cross-sectional, case–control study. Comparison of USE with conventional US using clinical examination as reference standard. | Symptomatic tendons were softer. The distal and middle third were more frequently involved than the proximal third of Achilles tendon. | USE detected more alterations in contralateral asymptomatic tendons than conventional US. USE has comparable accuracy to conventional US and clinical examination. USE showed good correlation with conventional US (κ = 0.89, p < 0.001), being greater for lesions of the distal third compared to the middle and proximal parts. Ac: 97%, Sp: 99.2%, Sv: 93.7% compared to standard clinical findings. Ac: 99%, Sp: 100%, Sv: 93% compared to conventional US. |
Sconfienza et al. 2010 [28] | 18 volunteers/36 asymptomatic tendons. 12 patients/12 tendons. | Cross-sectional, case–control study. Comparison of USE with conventional US/MRI using clinical symptoms as reference standard. | Symptomatic tendons were harder. No difference between symptomatic and control tendons at the enthesis and myotendinous junction. | USE showed good correlation with conventional US and MRI. |
Tan et al. 2012 [29] | 20 volunteers/40 asymptomatic tendons. 16 patients in post-operative period for tendon rupture correction/19 tendons. | Cross-sectional, case–control study. | Healing tendons demonstrated a harder and heterogeneous texture compared to the healthy ones. | |
Gehmert et al. 2012 [30] | 9 rabbits: 12 ruptured tendons, 6 tendons treated with stem cells, 6 ruptured tendons not treated, 6 healthy tendons. | Laboratory study with New Zealand white rabbits. | Treated tendons with stem cells had higher elasticity compared with those not treated. Stem cells restored the elastic properties of Achilles tendon. | |
Klauser et al. 2013 [31] | 10 cadavers/13 tendons. | Laboratory study using cadaveric models. Comparison with conventional US using clinical histology as reference standard. | Injured tendons were softer than asymptomatic tendons. | USE showed perfect agreement with histology results and moderate agreement with conventional US (κ = 0.52, p < 0.001). Sv: 100%, Sp: 100% (histologic findings as the reference standard). |
Turan et al. 2013 [32] | 41 patients with ankylosing spondylitis (AE)/82 tendons. 32 healthy volunteers/64 tendons. | Cross-sectional, case–control study. Comparison with conventional US using clinical examination as reference standard. | Distal third of Achilles tendon was softer on patients with AE compared with healthy individuals (p = 0.001) and it was associated with enthesopathy findings (p = 0.07). The intensity of achillodynia tended to be higher in patients with abnormal USE examination findings (p = 0.07). | USE had moderate to good correlation with conventional US (κ = 0.80 for proximal third, κ = 0.58 for middle third, κ = 0.39 for distal third). |
Evranos et al. 2015 [33] | 78 patients with diabetes: 35 patients with foot ulcers, 43 patients without foot ulcers, 33 healthy individuals | Cross-sectional, case–control study. | The Achilles tendon was softer in diabetic patients with foot ulcers than in patients without ulcers (p < 0.001) or in non-diabetics (p = 0.03). A softer medial third of the Achilles tendon was related to longer duration of diabetes, use of insulin, foot ulcers and presence of neuropathy or peripheral arterial disease. | |
Ooi et al. 2015 [34] | 120 patients/120 symptomatic tendons 120 volunteers/120 asymptomatic tendons | Cross-sectional, case–control study. Comparison with conventional US and functional scores using clinical examination as reference standard. | Symptomatic tendons were softer than asymptomatic tendons (SR = 1.70 ± 0.84 vs. 0.76 ± 0.30, p < 0.001). | USE had excellent sensitivity, specificity and diagnostic accuracy (Sv: 97.5%, Sp: 94.5%, Ac: 97.8%). USE had excellent correlation with clinical findings (k = 0.91, p < 0.05). USE showed good to excellent agreement with B-mode US (k = 0.81, p < 0.001). SR had moderate correlation with functional scores (ρ = − 0.62, p < 0.001). |
Busilacchi et al. 2016 [17] | 30 volunteers/60 asymptomatic tendons. 25 patients in post-operative period of tendon rupture correction/50 tendons. | Prospective cohort study. Comparison of USE with functional score. | After surgery, the tendons were harder and achieved a peak thickness 6 months after, compared to contralateral and control group tendons. Contralateral tendons were stiffer than control group tendons (p < 0.001). | SR had a negative correlation with functional score (ρ = − 0.42, p = 0.03). |
Onal et al. 2016 [35] | 42 acromegaly patients/84 tendons. 42 healthy volunteers/84 tendons. | Cross-sectional, case–control study. Comparison of USE with biological markers. | Achilles tendons in patients with acromegaly were softer than the healthy ones (p = 0.0001). | No significant correlation between USE and biological markers of the disease. |
Yamamoto et al. 2017 [36] | 24 New Zealand rabbits with Achilles tendon transection. | Laboratory study. SR calculation and mechanical testing of ultimate load, ultimate stress, elastic modulus and linear stiffness and histological analysis at weeks 2, 4, 8 and 12. | Mean SR at the healing site after Achilles tendon rupture gradually decreased and the Achilles tendon became significantly harder over time (p < 0.001). | SR showed correlation with all mechanical evaluations [ultimate stress (ρ = 0.68, p < 0.001), elastic modulus (ρ = 0.78, p < 0.001) and histologic evaluation of the healing site (ρ = 0.87, p < 0.001)]. |
Patellar tendon | ||||
Rist and Mauch 2012 [37] | 75 athletes: 37 asymptomatic tendons, 38 symptomatic tendons. | Cross-sectional, case–control study. | Symptomatic tendons showed higher strain scores than asymptomatic ones in longitudinal and cross-section. | |
Ooi et al. 2016 [38] | 35 volleyball athletes: 40 symptomatic tendons, 30 asymptomatic tendons. | Cross-sectional, case–control study. Comparison with conventional US using clinical examination as reference standard. | Symptomatic tendons were softer than asymptomatic tendons. | USE alone: Ac: 62.9%, Sv: 70%; Sp: 53.3%. USE + B-mode US: Ac: 61.4%, Sv: 82.5%, Sp: 33.3%. USE + power Doppler US: Ac: 60.0%, Sv: 72.5%, Sp: 43.3%. Specificity of USE alone and combined with conventional US were low. USE may increase conventional US sensitivity and accuracy in the diagnosis of patellar tendinopathy. Softening of symptomatic patellar tendons were better related with functional scores (p = 0.004) than conventional US (p = 0.10). |
Epicondylar tendons | ||||
De Zordo et al. 2009 [39] | 28 volunteers/44 asymptomatic tendons. 32 patients with lateral epicondylitis/38 symptomatic tendons. | Cross-sectional, case–control study. Comparison with conventional US using clinical examination as reference standard. | Symptomatic tendons were softer than asymptomatic tendons (p < 0.001). | Sv: 100%, Sp: 89%, Ac: 94%. USE had higher sensitivity and accuracy than conventional US in detecting clinically symptomatic epicondylar tendinopathy. USE had higher sensitivity than conventional US in detecting intratendinous and peritendinous lesions. Good correlation with conventional US findings (ρ ≥ 0.900, p < 0.001). |
Ahn et al. 2014 [40] | 79 patients and 14 healthy volunteers. 97 symptomatic tendons. 89 asymptomatic tendons. | Cross-sectional, case–control study. Comparison with conventional US and clinical parameters using clinical examination as reference standard. | Symptomatic tendons were softer (mean SR = 1.45 ± 0.45) than asymptomatic tendons (mean SR = 2.07 ± 0.70) (p < 0.001). | Significant correlation with conventional US (p < 0.001). |
Park et al. 2014 [41] | 28 patients with unilateral lateral epicondylitis: 14 symptomatic tendons, 14 asymptomatic tendons. | Cross-sectional, case–control study. Comparison with conventional US using clinical examination as reference standard. | Symptomatic tendons were softer than asymptomatic tendons. | USE alone: Sv: 96.4%, Sp: 96.4%, Ac: 96.4% (p < 0.01). USE had greater diagnostic accuracy compared to conventional echography (Ac: 96.4% vs. 89.5%, p < 0.01). USE was correlated with severity of tendon pathology estimated by conventional US (p < 0.01). USE was correlated with cortical irregularities around the lateral epicondyle, history of steroid injection and symptom duration (p < 0.05). USE findings had correlation with pain during resistive middle finger extension on physical examination (p < 0.05). |
Kocyigit et al. 2016 [42] | 17 volunteers with lateral epicondylitis/34 tendons. | Cross-sectional, case–control study. Comparison with conventional US using clinical examination as reference standard. | Symptomatic tendons were softer than asymptomatic tendons (p < 0.001). Mean SR: medial portion = 0.45 ± 0.12, middle portion = 0.44 ± 0.8, lateral portion = 0.47 ± 0.19. | USE was superior to conventional US distinguishing healthy tendons from those with tendinopathy. The SR of medial portion of the extensor tendon correlates with night pain (ρ = − 0.522, p = 0.03) and duration of symptoms (ρ = − 0.61, p = 0.01). |
Klauser et al. 2017 [43] | 16 cadavers/25 common flexor tendons. | Laboratory study using cadaveric models. Agreement comparison of conventional US and USE with histological evaluation. | Tendons with tendinopathy were softer than normal tendons. | USE combined with conventional US had better correlation (k = 0.84) with histology compared with the use of B-mode US (k = 0.57) or USE alone (k = 0.68) (p < 0.02). |
Klauser et al. 2017 [44] | 17 cadavers/26 common flexor tendons. | Laboratory study using cadaveric models. Agreement comparison of conventional US and USE with histological evaluation. | Tendons with tendinopathy were softer than normal tendons. | USE alone: Sv: 85%, Sp: 86%, Ac: 86%. USE + B-mode US: Sv: 95%, Sp: 81%, Ac: 92%. USE in combination with conventional US provided improved sensitivity (p < 0.02) without loss of specificity and had correlation with histology evaluation (κ = 0.78, p < 0.02). |
Rotator cuff tendons | ||||
Seo et al. 2014 [45] | 98 patients/101 shoulders with lesions (cuff tears, tendinopathies, adhesive capsulitis, calcific tendinitis, labral lesions). | Cross-sectional. Comparison of USE with conventional US/MRI using MRI findings as reference standard. | USE allowed quantification of the severity of adipose involution on the supraspinatus muscle tendon. | Sv: 95.6%, Sp: 87.5%, Ac: 91.1%. USE had excellent correlation with MRI (ρ = 0.855, p < 0.001) and conventional US (ρ = 0.793, p < 0.001). |
Seo et al. 2014 [46] | 118 patients/118 shoulders with supraspinatus tendinopathy. | Cross-sectional. Comparison of USE with conventional US/MRI using MRI findings as reference standard. | Tendons with tendinopathy had focal areas of softness. | Positive correlation between grades of MRI and USE (ρ = 0.829, p = < 0.001). Positive correlation between grades of US and USE (ρ = 0.723, p = < 0.001). |
Tudisco et al. 2015 [47] | 100 shoulders: 50 with supraspinatus tear, 50 healthy contralateral shoulders. | Cross-sectional, case–control study. Comparison of USE (SR) of the tendons between the two groups. Comparison of USE (SR) with demographic data and functional scores. | Mean SR in the affected shoulder (0.75 ± 0.08) was lower than the contralateral healthy shoulder (1.01 ± 0.07) (p < 0.0001). | Negative correlation between SR and VAS (Visual Analogue Scale) score for pain (r = − 0.76). Strong positive correlation between SR and functional scores. |
Kocyigit et al. 2016 [48] | 50 shoulders: 25 patients diagnosed with unilateral subacromial impingement, 25 healthy shoulders. | Cross-sectional, case–control study. Comparison of USE (including SR) of the tendons between the two groups. Comparison of SR of the tendons with demographic data and functional scores. | Decreased stiffness of the supraspinatus tendon of the affected shoulder compared to healthy shoulder (p < 0.001). | There was no correlation between the findings in USE and functional scores, gender and age. |
Lee et al. 2016 [49] | 39 patients with chronic supraspinatus tendinopathy. | Cross-sectional. Comparison of the supraspinatus tendon SR with the degree of tendinosis on MRI. | Positive correlation of SR with degree of tendinosis in MRI (p < 0.001). | |
Long head of biceps tendon (LHBT) | ||||
Seo et al. 2014 [50] | 34 patients/38 shoulders with tendinopathy of LHBT. 98 patients/114 shoulders without tendinopathy of LHBT. | Cross-sectional, case–control study. Comparison of USE between the two groups. Comparison with conventional US using clinical examination as reference standard. | Focal areas of softening in affected tendons. | Positive correlation between USE and conventional ultrasound (ρ = 0.585, p < 0.001). |
Quadriceps tendon | ||||
Teber et al. 2015 [51] | 53 patients with chronic renal failure undergoing dialysis/106 quadriceps tendons. 25 healthy individuals/50 quadriceps tendons. | Cross-sectional, case–control study. Comparison of USE of the quadriceps tendon between the two groups. | Quadriceps tendons in patients with chronic renal failure were softer (right knee, p = 0.03; left knee, p = 0.02) compared to controls. |
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). |