AUTHOR=Di Matteo Andrea , Moscioni Erica , Lommano Maria Giovanna , Cipolletta Edoardo , Smerilli Gianluca , Farah Sonia , Airoldi Carla , Aydin Sibel Zehra , Becciolini Andrea , Bonfiglioli Karina , Carotti Marina , Carrara Greta , Cazenave Tomas , Corradini Davide , Cosatti Micaela Ana , de Agustin Juan Josè , Destro Castaniti Giulia Maria , Di Carlo Marco , Di Donato Eleonora , Di Geso Luca , Elliott Ashley , Fodor Daniela , Francioso Francesca , Gabba Alessandra , Hernández-Díaz Cristina , Horvath Rudolf , Hurnakova Jana , Jesus Diogo , Marin Josefina , Martire Maria Victoria , Mashadi Mirza Riccardo , Massarotti Marco , Musca Alice Andreea , Nair Jagdish , Okano Tadashi , Papalopoulos Ioannis , Rosa Javier , Rosemffet Marcos , Rovisco João , Rozza Davide , Salaffi Fausto , Scioscia Crescenzio , Scirè Carlo Alberto , Tamas Maria-Magdalena , Tanimura Shun , Ventura-Rios Lucio , Villota-Eraso Catalina , Villota Orlando , Voulgari Paraskevi V. , Vreju Florentin Ananu , Vukatana Gentiana , Hereter Johana Zacariaz , Zanetti Anna , Grassi Walter , Filippucci Emilio TITLE=Reliability assessment of ultrasound muscle echogenicity in patients with rheumatic diseases: Results of a multicenter international web-based study JOURNAL=Frontiers in Medicine VOLUME=9 YEAR=2023 URL=https://www.frontiersin.org/journals/medicine/articles/10.3389/fmed.2022.1090468 DOI=10.3389/fmed.2022.1090468 ISSN=2296-858X ABSTRACT=Objectives

To investigate the inter/intra-reliability of ultrasound (US) muscle echogenicity in patients with rheumatic diseases.

Methods

Forty-two rheumatologists and 2 radiologists from 13 countries were asked to assess US muscle echogenicity of quadriceps muscle in 80 static images and 20 clips from 64 patients with different rheumatic diseases and 8 healthy subjects. Two visual scales were evaluated, a visual semi-quantitative scale (0–3) and a continuous quantitative measurement (“VAS echogenicity,” 0–100). The same assessment was repeated to calculate intra-observer reliability. US muscle echogenicity was also calculated by an independent research assistant using a software for the analysis of scientific images (ImageJ). Inter and intra reliabilities were assessed by means of prevalence-adjusted bias-adjusted Kappa (PABAK), intraclass correlation coefficient (ICC) and correlations through Kendall’s Tau and Pearson’s Rho coefficients.

Results

The semi-quantitative scale showed a moderate inter-reliability [PABAK = 0.58 (0.57–0.59)] and a substantial intra-reliability [PABAK = 0.71 (0.68–0.73)]. The lowest inter and intra-reliability results were obtained for the intermediate grades (i.e., grade 1 and 2) of the semi-quantitative scale. “VAS echogenicity” showed a high reliability both in the inter-observer [ICC = 0.80 (0.75–0.85)] and intra-observer [ICC = 0.88 (0.88–0.89)] evaluations. A substantial association was found between the participants assessment of the semi-quantitative scale and “VAS echogenicity” [ICC = 0.52 (0.50–0.54)]. The correlation between these two visual scales and ImageJ analysis was high (tau = 0.76 and rho = 0.89, respectively).

Conclusion

The results of this large, multicenter study highlighted the overall good inter and intra-reliability of the US assessment of muscle echogenicity in patients with different rheumatic diseases.