Scintigraphy versus pH probe for quantification of pediatric gastroesophageal reflux: a study using concurrent multiplexed data and acid feedings.

We performed 12 simultaneous scintigraphic and pH probe studies in children being evaluated for reflux to determine the ability of scintigraphic images in comparison to pH probe data to quantify gastroesophageal reflux in children and to identify an optimal scintigraphic framing interval. We used a multiplexor to synchronize exactly the scintigraphy and pH probe and an acid meal to avoid missing postprandial episodes with the pH probe. We reformatted the studies in both 60-sec and 10-sec images to compare the two framing intervals. The 60-sec images produced better agreement between pH probe and scintigraphy than the 10-sec images for both the number of reflux episodes and the duration of reflux. Of the 64 reflux episodes detected by either method at this coarser framing interval, scintigraphy detected 80%, the pH probe detected 63% and both methods concurrently detected 42%. Of the 681 60-sec images aggregated across patients, scintigraphy detected 55% of those with intraesophageal refluxate, the pH probe detected 96% and both tests concurrently detected 51%. Within patients, the number of positive scintigraphic images in the postprandial hour correlated with the number of images with pH < 4 during the same hour (p = 0.008, and p < 0.0001 if two patients with very rapid gastric emptying are excluded), but not with the results of the 24-hr pH probe study. A 1-hr scintigraphic study formatted in 60-sec frames provides a quantitative representation of postprandial gastroesophageal reflux for children, particularly if they do not have rapid gastric emptying.