Influence of frame rate in detecting oropharyngeal aspiration in paediatric videofluoroscopic swallow studies - An observational study

Objectives: The videofluoroscopic swallow study (VFSS), currently the gold standard for assessing aspiration in children, incurs radiation. Adhering to the ALARA principle is crucial in minimising radiation dose whilst obtaining accurate diagnostic information in children. International adult VFSS guidelines recommend a capture rate of 30 frames per second (fps). Higher capture rates increase radiation yet there is limited evidence on best practice VFSS capture rates in children, particularly on thin fluid consistency-the fastest viscosity with the highest potential for missed aspiration on slower capture rates. We aimed to determine if image acquisition at 30fps versus 15fps alters the accuracy of detecting aspiration when assessing thin fluids during paediatric VFSS. Materials & Methods: Seventeen speech language pathologists (SLPs) blindly rated a total of 2,356 swallow loops for the presence/absence of aspiration from VFSS recordings of 13 infants/children drinking thin fluids. 76 swallow loops were randomly presented at 15 versus 30fps, on two occasions. Area under receiver operating curve (aROCs) was used to compare the accuracy of aspiration ratings at 15 versus 30fps compared to a comparison set. The intraclass correlation coefficient (ICC) was used to examine rater reliability. Results: Accuracy for detecting aspiration was near-identical at 15fps (aROC:0.97; 95%CI:0.96-0.97) and 30fps (0.96; 95%CI 0.96-0.97). Good inter-rater (ICC:0.82; 95%CI:0.72-0.89) and intra-rater reliability among the raters (ICC:0.89; 95%CI:0.82-0.93) was found. Conclusion: Using 15fps in paediatric VFSS when assessing thin fluid consistency aspiration provides a similar detection rate to using 30fps. As 15fps would have a lower radiation dose than 30fps, we recommend using 15fps when undertaking VFSS in children. Clinical relevance statement: Adhering to the ALARA principles, a capture rate of 15fps should be used in paediatric VFSS for assessment on thin fluids.