Optimal timing of the first barium swallow examination for diagnosis of pyriform sinus fistula

OBJECTIVE. Observation of a sinus tract during a barium swallow examination is important for the diagnosis of pyriform sinus fistula; however, to our knowledge, no reports have existed regarding the optimal timing of the examination in relation to the onset of symptoms. The purpose of this study was to compare the timing of the examination, patient age, the number of inflammatory episodes that occurred before the examination, and the barium concentration used for examinations with true-positive results versus those with false-negative results for the diagnosis of pyriform sinus fistula. MATERIALS AND METHODS. Twenty-three children with pyriform sinus fistula were included. The timing of the examination, patient age, the number of the inflammatory episodes that occurred before examination, and the barium concentration used were compared between examinations with true-positive results and examinations with false-negative results, by use of the Mann-Whitney U test. RESULTS. The examination had true-positive results for 60.9% (14/23) of patients and false-negative results for 39.1% (9/23) of patients. The mean (± SD) interval since the onset of symptoms was significantly shorter for patients with false-negative examination results than for those with true-positive examination results (26.33 ± 21.17 days vs 48.57 ± 17.67 days; p = 0.020). By 6 weeks after the onset of symptoms, more than half of the examinations had false-negative results. No significant difference in patient age (p = 0.238) or number of previous inflammatory episodes (p = 0.431) existed between examinations with true-positive and false-negative results; however, a significant difference was noted in the mean barium concentration used (88.57% ± 31.53% vs 52.86% ± 18.68% weight/volume, respectively; p = 0.014). CONCLUSION. Barium swallow examinations with false-negative results were significantly more likely when the examination was performed soon after the onset of symptoms. Therefore, early first examinations would not be recommended for the diagnosis of pyriform sinus fistula, especially in terms of radiation exposure. A higher barium concentration may be useful.