Reliability of fluoroscopic examination of nasopharyngeal dorsoventral dimension change in pugs and French bulldogs

ObjectiveTo compare intra- and interobserver agreements in two-dimensional measurements of changes in nasopharyngeal dimensions during breathing in pugs and French bulldogs. Study designExperimental randomized study. AnimalsA total of 20 French bulldogs and 16 pugs. MethodsFour observers with different levels of experience measured the dorsoventral dimensions of the nasopharynx during inspiration and expiration on fluoroscopy videos. Measurements were performed at the maximal narrowing of the nasopharynx for the functional method and at the level of the tip of the epiglottis for the anatomically adjusted method. The intra- and interobserver agreements of the measurements, ratio of the dynamic nasopharyngeal change (Delta L), and grade of nasopharyngeal (NP) collapse (no, partial or complete) were evaluated. ResultsThe functional method resulted in intraobserver correlation coefficients of 0.532 (p < .01) and 0.751 (p < .01) and interobserver correlation coefficients of 0.378 (p < .01) and 0.621 (p < .01) for NP collapse grade and Delta L, respectively. The anatomically adjusted method, 0.491 (p < .01) and 0.576 (p < .01) and 0.495 (p < .01) and 0.729 (p < .01) for NP collapse grade and Delta L, respectively, were being used. One observer (radiologist) achieved intraobserver correlation coefficients >0.9 for both methods. ConclusionFair interobserver agreement was found for NP collapse grade (functional method), moderate intra- and interobserver agreements were found for NP collapse grade and Delta L (both methods) while intraobserver agreement for Delta L was good (functional method). Clinical significanceBoth methods seem repeatable and reproducible but only for experienced radiologists. The use of Delta L may offer higher repeatability and reproducibility than grade of NP collapse regardless of the method used.