Reproducibility of gastric emptying assessed with scintigraphy in patients with upper GI symptoms

Background: The reproducibility of gastric emptying (GE) measured with scintigraphy in patients is poorly understood. Our aims were to assess the intra and inter-individual reproducibility of these parameters in patients with upper gastrointestinal symptoms. Methods: Sixty patients (21 diabetics, 39 non-diabetics) with upper gastrointestinal symptoms underwent scintigraphic-assessment of GE of a solid meal (296 kcal, 30% fat) over 4 hours on two occasions at an average interval of 15 days. The concordance correlation coefficient (CCC), intra and inter-individual coefficients of variation (COV) of GE endpoints were analyzed. Results: The GE t_1/2 was 134 ± 8 minutes (mean ± SEM) for the first and 128 ± 6 minutes for the second study. The mean (95% CI) CCC between the two studies was 0.79 (0.67, 0.87) for GE at 1 hour, 0.83 (0.75, 0.9) for GE at 2 hours, 0.54 (0.34, 0.7) for GE at 4 hours, and 0.79 (0.68, 0.86) for GE t_1/2. However, in 18 of 60 patients (30%), the characterization of GE as normal, delayed, or rapid differed between the first and second studies. For gastric empting t_1/2, the inter-individual coefficients of variation was 40%; the intra-individual COV was 20%, comparable in diabetics and non-diabetics, and greater in patients with rapid (28%) than delayed (18%) or normal GE (12%). Conclusions & Inferences: Among patients with upper gastrointestinal symptoms, GE measured with scintigraphy is relatively reproducible. In 30% of cases, the interpretation was different between the two assessments. Hence, a diagnosis of gastroparesis based on a single study may occasionally be inaccurate.