Reflux scintigraphy in gastro-esophageal reflux disease: a comparison study with 24 hour pH-impedance monitoring

Objective: Reflux scintigraphy is often used to diagnose gastro-esophageal reflux disease (GERD). However, the efficacy of this study remains controversial. Our aim was to determine the role of reflux scintigraphy in diagnosing GERD by comparing it to 24 h combined pH-impedance study as the gold standard. Materials and methods: Adult patients who presented for investigations of reflux symptoms were prospectively recruited into the study. All patients underwent high resolution esophageal manometry and those with major motor disorders of the esophagus were excluded. Eligible patients immediately underwent reflux scintigraphy following insertion of the pH-impedance catheter. Results: Thirty patients were included in the study. Using a total acid exposure time (AET) of >4.2% as the reference for abnormal acid reflux, reflux scintigraphy had a sensitivity and specificity of 62.5 and 68.2%, respectively, in detecting acid reflux. When compared to AET >6%, reflux scintigraphy had a sensitivity and specificity of 66.7 and 62.5%, respectively, and a positive predictive value of 30.8% and a negative predictive value of 88.2%. There were no associations between outcomes of reflux scintigraphy and total AET (p =.46), total (acid or non-acid) reflux events (p = 0.11), proximal AET (p =.33) or the number of proximal reflux episodes (p =.75) on 24 h pH-impedance study. Conclusions: Reflux scintigraphy has limited role in diagnosing GERD when compared to 24 h combined pH-impedance monitoring.