Discriminative and convergent validity of strain elastography for detecting tendinopathy within the supraspinatus tendon: a cross-sectional study.

BACKGROUND: We aimed to explore the discriminative validity of ultrasound strain elastography (SEL) between patients with painful supraspinatus tendinopathy and healthy control shoulders, as well as the associations between SEL and magnetic resonance imaging (MRI), conventional ultrasound (tendon thickness), and the Disabilities of the Arm, Shoulder and Hand questionnaire (DASH). METHODS: Thirty patients with shoulder pain and MRI-verified supraspinatus tendinopathy and 30 healthy control shoulders (no pain) were examined using SEL, MRI, and conventional ultrasound of the supraspinatus tendon. SEL variables included raw data, ratios between the deltoid muscle and supraspinatus tendon (deltoid ratio), color rating, and presence of red/yellow lesions (middle, worst part, and total tendon). RESULTS: Statistically significant increases in odds ratios for being symptomatic (increased softening) were seen for all raw data variables, corresponding to 3.978 (95% confidence interval [CI], 1.414-11.197) for middle, 4.602 (95% CI, 1.536-13.788) for worst, and 4.865 (95% CI, 1.406-16.836) for total tendon, and 1.260 (95% CI, 1.027-1.545) for the deltoid ratio (worst), adjusted for sex and body mass index (BMI). Tendon thickness was not associated with SEL; however, significantly positive associations were found between raw data variables and MRI (ß ≥ 0.58, P < .01), and positive associations were found between raw data variables and the DASH score (ß = 0.01, P ≤ .04), adjusted for sex and BMI. CONCLUSIONS: Raw data variables and the deltoid ratio (worst) discriminated between patients with painful supraspinatus tendinopathy and healthy control shoulders when adjusted for sex and BMI. Associations were statistically significant for raw data variables and MRI or DASH score when adjusted for sex and BMI. Further studies are needed to understand SEL and the role of sex and BMI, including the responsiveness of SEL.

Strain Elastography and Tendon Response to an Exercise Program in Patients With Supraspinatus Tendinopathy: An Exploratory Study.

BACKGROUND: Shoulder pain is common, with a lifetime prevalence of up to 67%. Evidence is conflicting in relation to imaging findings and pain in the shoulder. Sonoelastography can be used to estimate tissue stiffness and may be a clinically relevant technique for diagnosing and monitoring tendon healing. PURPOSE: To evaluate changes in supraspinatus tendon stiffness using strain elastography (SEL) and associations with changes in patient-reported outcomes, supraspinatus tendon thickness, and grade of tendinopathy after 12 weeks of unilateral shoulder exercises in patients with supraspinatus tendinopathy. STUDY DESIGN: Controlled laboratory study. METHODS: A total of 23 patients with unilateral clinical supraspinatus tendinopathy performed 12 weeks of "standard care" exercises. At baseline and follow-up, supraspinatus tendon stiffness was measured bilaterally using SEL and compared with tendinopathy grading on magnetic resonance imaging scans and tendon thickness measured using conventional ultrasound. Patient-reported outcome measures included physical function and symptoms from the Disabilities of the Arm, Shoulder and Hand questionnaire and pain rating (visual analog scale). RESULTS: No significant changes in SEL within or between groups (asymptomatic vs symptomatic tendon) were seen. All patient-reported outcomes showed significant improvement from baseline to follow-up, but with no change in tendinopathy grading and tendon thickness. No significant differences in the proportion of patients changing above the minimal detectable change in SEL and PROM were seen, except for discomfort while sleeping. CONCLUSION: Despite no significant within-group or between-group changes in SEL, significant improvements were found in patient-reported outcomes. An acceptable agreement between patients changing above the minimal detectable change in SEL and patient-reported outcome measure was seen. Further studies should explore the use of SEL to detect changes after tendon repair and long-term training potentially in subgroups of different tendinopathy phases. CLINICAL RELEVANCE: In the short term, structural changes in supraspinatus tendons could not be visualized using SEL, indicating that a longer time span should be expected in order to observe structural changes, which should be considered before return to sports. Subgrouping based on stage of tendinopathy may also be important in order to evaluate changes over time with SEL among patients with supraspinatus tendinopathy. REGISTRATION: NCT03425357 (ClinicalTrials.gov identifier).

Musculoskeletal application and validation of speckle-tracking ultrasonography.

BACKGROUND: Diseased, injured, or dysfunctional skeletal muscles may demonstrate abnormal function and contractility. Currently, only few in vivo imaging techniques are able to characterize the contractile properties of muscle tissue. This study aimed to test the hypothesis that muscle strain can be tracked in two upper extremity skeletal muscles by speckle-tracking ultrasonography (STU) and correlates with isometric muscle contractions. METHODS: A convenience sample of 10 healthy, adult volunteers with normal shoulder function were tested. The 5 women and 5 men had a mean age of 45 years (range: 39-59 years) and BMI < 30. STU was applied to the supraspinatus (SS) and biceps brachii (BB) muscles using a M11 L-MHz linear transducer (frequency 8-15 MHz) hooked to a Vivid E 9TM ultrasound machine. Strain validation was performed by correlating peak strain against standardized sub-maximal, isometric load conditions of the two muscles (20-80% of maximal voluntary contraction) using a custom-built muscle dynamometer based on strain-gauge technique. Data were analyzed offline using the EchoPac speckle-tracking software and were blinded to the examiner. RESULTS: Intramuscular strain measured by STU in the SS and BB muscles showed moderate to strong correlations with external muscle load (SS: r = - 0.76, p < 0.0001 and BB: r = - 0.60, p < 0.0001). We found strain to vary from approximately 10-20% during increasing submaximal, isometric conditions. CONCLUSIONS: We demonstrate that STU can be applied on healthy skeletal musculature (SS and BB muscles). The observed correlations between strain and isometric contractions suggest a valid technique. However, the concept of measuring muscle strain non-invasively needs further investigation for validity, accuracy, responsiveness, and reliability before its therapeutic and research potential can be realized.

Ultrasonic strain elastography for detecting abnormalities in the supraspinatus tendon: an intra- and inter-rater reliability study.

OBJECTIVES: The reliability of ultrasonic strain elastography (SEL) used to detect abnormalities in the supraspinatus tendon is unclear. Thus, the aim of this study was to investigate the reliability of SEL in the supraspinatus tendon. DESIGN: An intra-rater and inter-rater reliability study. SETTING: A single-centre study conducted at the University of Southern Denmark. PARTICIPANTS: Twenty participants with shoulder pain and MRI-verified supraspinatus tendinosis and 20 asymptomatic participants (no MRI). PRIMARY AND SECONDARY OUTCOME MEASURES: Raw values (RAW) and ratios (deltoid muscle (DELT) and gel pad (GEL) as reference tissues) were calculated and mean values of measurements from three regions of the supraspinatus tendon were reported. Colour scale ratings and number of yellow/red lesions from the three areas were also included. RESULTS: Intra-rater reliability showed intraclass correlation coefficients (ICCs) for RAW, DELT and GEL: 0.97 (minimal detectable change (MDC): 0.28 (6.36% of the mean)), 0.89 (MDC: 2.91 (20.37%)) and 0.73 (MDC: 1.61 (58.82%)), respectively. The ICCs for inter-rater reliability were 0.89 (MDC: 0.47 (10.53%)), 0.78 (MDC: 3.69 (25.51%)) and 0.70 (MDC: 1.75 (62.63%)), respectively.For colour scale ratings, intra-rater reliability (linear weighted kappa) ranged from 0.76 to 0.79, with the inter-rater reliability from 0.71 to 0.81. For the number of lesions, intra-rater reliability ranged from 0.40 to 0.82 and inter-rater reliability from 0.24 to 0.67. CONCLUSIONS: Intra-rater and inter-rater reliability were excellent for raw values and for ratios with deltoid muscle as the reference tissue, and good for ratios with gel pad as the reference tissue. The reliability of colour scale ratings was substantial-to-almost perfect, and for the number of lesions fair-to-almost perfect.Although high reliability was found, validity and responsiveness of these elastographic methods needs further investigation. ETHICS APPROVAL: The study protocol was approved by the Ethics Committee for the Region of South Denmark (S-20160115) and reported to the Danish Data Protection Agency (2014-41-3266).

Microdose acquisition in adolescent leg length discrepancy using a low-dose biplane imaging system.

Background Children with leg length discrepancy often undergo repeat imaging. Therefore, every effort to reduce radiation dose is important. Using low dose preview images and noise reduction software rather than diagnostic images for length measurements might contribute to reducing dose. Purpose To compare leg length measurements performed on diagnostic images and low dose preview images both acquired using a low-dose bi-planar imaging system. Material and Methods Preview and diagnostic images from 22 patients were retrospectively collected (14 girls, 8 boys; mean age, 12.8 years; age range, 10-15 years). All images were anonymized and measured independently by two musculoskeletal radiologists. Three sets of measurements were performed on all images; the mechanical axis lines of the femur and the tibia as well as the anatomical line of the entire extremity. Statistical significance was tested with a paired t-test. Results No statistically significant difference was found between measurements performed on the preview and on the diagnostic image. The mean tibial length difference between the observers was -0.06 cm (95% confidence interval [CI], -0.12 to 0.01) and -0.08 cm (95% CI, -0.21 to 0.05), respectively; 0.10 cm (95% CI, 0.02-0.17) and 0.06 cm (95% CI, -0.02 to 0.14) for the femoral measurements and 0.12 cm (95% CI, -0.05 to 0.26) and 0.08 cm (95% CI, -0.02 to 0.19) for total leg length discrepancy. ICCs were >0.99 indicating excellent inter- and intra-rater reliability. Conclusion The data strongly imply that leg length measurements performed on preview images from a low-dose bi-planar imaging system are comparable to measurements performed on diagnostic images.

Ultrasound assessment for grading structural tendon changes in supraspinatus tendinopathy: an inter-rater reliability study.

AIM: To evaluate the inter-rater reliability of measuring structural changes in the tendon of patients, clinically diagnosed with supraspinatus tendinopathy (cases) and healthy participants (controls), on ultrasound (US) images captured by standardised procedures. METHODS: A total of 40 participants (24 patients) were included for assessing inter-rater reliability of measurements of fibrillar disruption, neovascularity, as well as the number and total length of calcifications and tendon thickness. Linear weighted κ, intraclass correlation (ICC), SEM, limits of agreement (LOA) and minimal detectable change (MDC) were used to evaluate reliability. RESULTS: 'Moderate-almost perfect' κ was found for grading fibrillar disruption, neovascularity and number of calcifications (k 0.60-0.96). For total length of calcifications and tendon thickness, ICC was 'excellent' (0.85-0.90), with SEM(Agreement) ranging from 0.63 to 2.94 mm and MDC(group) ranging from 0.28 to 1.29 mm. In general, SEM, LOA and MDC showed larger variation for calcifications than for tendon thickness. CONCLUSIONS: Inter-rater reliability was moderate to almost perfect when a standardised procedure was applied for measuring structural changes on captured US images and movie sequences of relevance for patients with supraspinatus tendinopathy. Future studies should test intra-rater and inter-rater reliability of the method in vivo for use in clinical practice, in addition to validation against a gold standard, such as MRI. TRIAL REGISTRATION NUMBER: NCT01984203; Pre-results.