Can We Reduce Frame Rate to 15 Images per Second in Pediatric Videofluoroscopic Swallow Studies?

Videofluoroscopic Swallow studies (VFSS) are useful radiological examinations to explore swallowing disorders but which require ionizing radiation. The aim of our study was to evaluate the comparability of pediatric VFSS at 15 frames per second (fps) with 30 fps. Fifty-five loops including 190 swallowings of VFSS at 30 fps performed on 32 consecutive pediatric patients in a University Hospital Center were retrospectively modified by a software to delete one image out of two to obtain secondary loops with a frame rate of 15 fps. An otorhinolaryngologist-phonatrician and a radiologist reviewed all swallowings blindly and randomly using the penetration and aspiration scale (PAS). In case of discordance, they concluded a consensual interpretation. Fifteen girls and seventeen boys were included. The median age was 4 years and 8 months (range = 4 months-16 yr.). 144 swallowings were normal. Swallowing disorder was confirmed in 46 swallowings, (23 supraglottic penetrations and 23 aspirations). Considering each swallowing at 15 fps, sensitivity and specificity were, respectively, 93% (CI 0.82-0.98) and 98% (CI 0.94-0.99). The Cohen'Kappa coefficient between each interpretation at 15 and 30 fps was "almost perfect" (κ = 0.95; CI 0.88-0.99). Considering each loop, conclusion was identical. Reducing frame rate at 15 fps during pediatric VFSS seemed to be acceptable with comparable diagnostic performances without clinical impact compared to 30 fps, while being an efficient way to reduce the ionizing radiation exposition in children. We would suggest reconsidering the possibility of using VFSS with a 15 fps in a pediatric population.