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

Abstract

AimTo 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.MethodsA 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.ConclusionsInter-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 numberNCT01984203; Pre-results.

Staging achilles tendinopathy using ultrasound imaging: the development and investigation of a new ultrasound imaging criteria based on the continuum model of tendon pathology

“…Similarly, the current results are higher than those reported for the patella tendon (k 0.45-0.76) and similar to those reported for the supraspinatus tendon (k 0.96-0.98). 32 The differences in reliability seen from the current study compared with those previously reported may be due to the design of the criteria used in the current study. While Sunding et al 33 used a scale based on subjective interpretations of the quantity of blood vessels present ('mild', 'moderate' and 'severe'), the current study used more objective measures such as number and size of blood vessels present.…”

“…33 49 When comparing the current results with those of other studies that have measured echogenicity in different tendons, Open access intra-rater agreement was lower than those reported for the patella tendon (k 0.78-0.87) 33 and similar to those reported for the supraspinatus tendon (k 0.76-0.79). 50 However, the proposed criteria used within the current study demonstrated better inter-rater agreement than that previously reported for the patella tendon (k 0.52-0.60) 33 and supraspinatus tendon (k 0.51-60), 32 and it is comparable with using sonoelastography to assess echogenicity for the supraspinatus tendon (k 0.71-0.81). 50 Agreement on structural changes within a tendon is considered difficult, with previous studies using an ordinal scale ('normal', 'mild abnormality', 'severe abnormality') that stages tendinopathy according to subtle changes that may be difficult to distinguish from anisotropy.…”

“…While Sunding et al 33 used a scale based on subjective interpretations of the quantity of blood vessels present ('mild', 'moderate' and 'severe'), the current study used more objective measures such as number and size of blood vessels present. Similarly, Ingwersen et al 32 used a more objective measure of the amount of Doppler activity present, expressed as a percentage of the region of interest (<25%, 25%-50%, >50%), hence the similarity of results to the current study.…”

“…While standardised imaging procedures, settings and machines have been shown to increase reliability, 32 33 46 51 there is a question as to whether there is transferability to the clinical setting, where images are captured using a variety of machines and imaging procedures. 32 Standardised protocols can make reliability appear artificially high when compared with the clinical setting, 32 however if reliability is low with a standardised protocol, reliability can be assumed to be poor and less relevant for the clinical setting. 32 Additionally, included images were static in nature which may affect the external validity and reliability of the criteria as clinically USI is considered a dynamic investigation.…”

“…11 29-31 The relative risk (RR) for developing pain in asymptomatic (clinical tests negative with structural changes on imaging) Achilles tendinopathy has been reported as 5.45-7.33. 30 31 While USI is useful for detecting tendon structural change, it is considered an operator-dependent modality, and standardised practices for both capturing and assessing ultrasound images can increase inter-rater reliability when assessing neovascularity, structural change, calcification (k 0.46-0.96) and tendon thickness (ICC 0.85-0.98) for tendinopathy in both the upper limb 32 and lower limb. 33 Although the standardisation of criteria for assessing tendon structural change improves reliability, there is significant heterogeneity of USI-based diagnostic criteria.…”