Intermachine Variation of Ultrasound Strain Elastographic Measures of the Quadriceps and Patellar Tendons in Healthy Participants

Abstract

Objectives: To evaluate inter-machine variation and compare intra-and inter-operator agreement and repeatability characteristics of two ultrasound systems for strain elastography measurements of quadriceps and patellar tendons.Methods: Forty tendons from 20 healthy participants were investigated by operators with different experience (operator 1; 12 years' ultrasound and >50 strain elastography (SE) examinations, operator 2; no ultrasound experience, 1 day SE training). Repeated measures were performed employing GE and esaote ultrasound systems. Percentage agreement, Cohen's kappa, intra-class correlation coefficient, and correlation tests assessed agreement, repeatability and associations of SE measures. Paired T-Test and Wilcoxon signed rank assessed differences in SE measures.Results: The study partipants included 5 males, 15 female volunteers; mean (range) age 29.3 (21-39) years). Better agreement and repeatability characteristics were observed for the patellar compared to the quadriceps tendon, and colour score (CS) method over the elasticity ratio (ER). Intra-operator agreement was better for the experienced operator. Intra-operator repeatability was achieved in 55% of ER (ICC, 0.40-0.91, p<0.05) and 77-85% (k, -0.25-1) of CS measures. Inter-operator repeatability was achieved in 35% (t/z, -2.93-7.94, p, 0.000-0.048) of all ER measures. No significant difference in proximal (z, -0.13--0.78) and distal patellar (z, -1.52-2.26, p>0.5) ER measures were observed. 74-75% mean agreement (k, 0-0.5) for CS measures comparable across both ultrasound systems was observed. Intermachine ER associations were poor (r, -0.39-0.13, p>0.05), whereas greater than 70% agreement (k, -0.87-0.53) for CS was achieved.Conclusions: Reproducibility of knee tendon strain elastography measurements is influenced by operator experience, ultrasound system, and tendon site.

Reliability of Sonoelastography Measurements of Lower Limb Tendon Properties: A Systematic Review

“…After formal request of additional data, authors of 5 studies (Dickson, et al 2020, Dickson, et al 2019, Helfenstein-Didier, et al 2016, Payne, et al 2018, Payne, et al 2017) provided 95% CI for ICC values.…”

“…Item 4: only 1 study (Dickson, et al 2020) specified the rater population of interest in the introduction, Item 6: only 3 studies (Alsiri, et al 2020, Ünal, et al 2019, Yamamoto, et al 2016) explained in the methods how sample size was chosen, Item 7: 8 out of 24 studies described the sampling methods, Item 11: 5 out of 24 studies stated, in the results section, the actual number of raters and subjects included.…”

“…Two studies (Dickson, et al 2020, Dickson, et al 2019) shared part of the dataset, therefore intra-rater reliability values obtained with the GE ultrasound device were reported only for the study by Dickson et al (2019) eliminating the other study (Dickson, et al 2020).…”

“…Inter-rater agreement of strain ratio using a t-test (p values) (Dickson, et al 2020) revealed mixed results with good values only documented for the proximal and distal part of the PT (Table 3). Inter-machine association using strain ratios was evaluated in one study (Dickson, et al 2020) showing significant results indicating no association between the two ultrasound devices for the PT.…”

Concurrent validity and intrarater reliability of two ultrasound-based methods for assessing patellar tendon stiffness

“…Two recent studies focused on intra- and interrater reliability for SEL applied to the patellar tendon and concluded that tendon site, operator experience and US system influence the reproducibility. 18,19 However, this method is still in its infancy and requires further validation. When applying SEL, use of a reference stiffness of an adjacent tissue is recommended.…”