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.
Reliability assessment of ultrasound muscle echogenicity in patients with rheumatic diseases: Results of a multicenter international web-based study / 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. - In: FRONTIERS IN MEDICINE. - ISSN 2296-858X. - 9:(2023), p. 1090468. [10.3389/fmed.2022.1090468]