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FN1Authors' addresses: Nadia Solomon and Calum N. L. Macpherson, Windward Islands Research and Educational Foundation (WINDREF), St. George's, Grenada, and St. George's University School of Medicine, St. George's, Grenada, E-mails: firstname.lastname@example.org and email@example.com. Paul J. Fields, Windward Islands Research and Educational Foundation (WINDREF), St. George's, Grenada, E-mail: firstname.lastname@example.org. Francesca Tamarozzi, WHO Collaborating Centre for Clinical Management of Cystic Echinococcosis, University of Pavia, Pavia, Italy, E-mail: email@example.com. Enrico Brunetti, WHO Collaborating Centre for Clinical Management of Cystic Echinococcosis, University of Pavia, Pavia, Italy, and Department of Infectious Diseases, San Matteo Hospital Foundation, Pavia, Italy, E-mails: firstname.lastname@example.org.
- The American Society of Tropical Medicine and Hygiene,
- Source: The American Journal of Tropical Medicine and Hygiene, Volume 96, Issue 3, Mar 2017, p. 686 - 691
Expert Reliability for the World Health Organization Standardized Ultrasound Classification of Cystic Echinococcosis
Cystic echinococcosis (CE), a parasitic zoonosis, results in cyst formation in the viscera. Cyst morphology depends on developmental stage. In 2003, the World Health Organization (WHO) published a standardized ultrasound (US) classification for CE, for use among experts as a standard of comparison. This study examined the reliability of this classification. Eleven international CE and US experts completed an assessment of eight WHO classification images and 88 test images representing cyst stages. Inter- and intraobserver reliability and observer performance were assessed using Fleiss' and Cohen's kappa. Interobserver reliability was moderate for WHO images (κ = 0.600, P < 0.0001) and substantial for test images (κ = 0.644, P < 0.0001), with substantial to almost perfect interobserver reliability for stages with pathognomonic signs (CE1, CE2, and CE3) for WHO (0.618 < κ < 0.904) and test images (0.642 < κ < 0.768). Comparisons of expert performances against the majority classification for each image were significant for WHO (0.413 < κ < 1.000, P < 0.005) and test images (0.718 < κ < 0.905, P < 0.0001); and intraobserver reliability was significant for WHO (0.520 < κ < 1.000, P < 0.005) and test images (0.690 < κ < 0.896, P < 0.0001). Findings demonstrate moderate to substantial interobserver and substantial to almost perfect intraobserver reliability for the WHO classification, with substantial to almost perfect interobserver reliability for pathognomonic stages. This confirms experts' abilities to reliably identify WHO-defined pathognomonic signs of CE, demonstrating that the WHO classification provides a reproducible way of staging CE.