Interobserver agreement in assessing plain radiographs of maxillary sinus.

Interrater agreement of six observers in interpreting maxillary sinus plain X-ray films was assessed. Patients aged 1-15 years old were enrolled and X-rays in the Caldwell and Waters's views were requested to confirm diagnosis of sinusitis or after antimicrobial therapy for a pre-existing sinusitis. One-hundred and one pairs of maxillary sinus radiographs from 101 patients were submitted to an independent and blind interpretation by three radiologists and three pediatricians. Each maxillary sinus was separately analyzed. Kappa statistic was used to measure interobserver agreement. A fair degree of agreement among the six raters was found on analyzing these films: 0.39 (95% CI, 0.36-0.41) for the right maxillary sinus and 0.37 (95% CI, 0.34-0.39) for the left one. These results stress literature data on the limits of plain radiographs for diagnosing maxillary sinusitis. The necessity of knowing the clinical findings while interpreting the exams also was depicted.