Evaluation of an inexpensive screening scintigraphic test of gastric emptying

Our goal was to study the accuracy of a limited assessment relative to the traditional and obtain a more detailed approach to measure gastric emptying. Methods: We prospectively evaluated 35 patients referred to our laboratory with suspected fast or slow gastric emptying. Transit was measured radioscintigraphically after ingestion of an egg meal containing ^99mTc- Amberlite pellets. Gastric emptying was analyzed by power exponential analysis. Diagnostic accuracy of simpler indices (gastric residual at 2 and 4 hr) was determined by comparing the categorization of patients as normal or abnormal relative to previously published normal data from our laboratory. Results: Gastric residual at 2 hr showed greater diagnostic accuracy for accelerated gastric emptying with 90% sensitivity at 90% specificity. Gastric residual at 4 hr was less accurate for accelerated emptying, but was more accurate at detecting delayed gastric emptying with 100% sensitivity at 70% specificity. In contrast, sensitivity and specificity of gastric residual at 2 hr for slow emptying were low (100% sensitivity with 20% specificity) emphasizing the importance of obtaining a scan later than 2 hr for detecting delayed gastric emptying. Conclusion: Selective scans taken at 2 and 4 hr provide an excellent screening test for detecting fast or slow gastric emptying; the accuracy of 2-hr data is optimal for accelerated emptying and that of the 4-hr data greater for delayed emptying. This strategy provides a simple, less expensive way to evaluate gastric emptying in clinical practice with acceptable sensitivity and specificity as an initial test for patients with clinically suspected gastric stasis or dumping syndromes.