Are nuclear medicine procedures clinically useful in localizing GI bleeding, or are simpler techniques adequate?
99m Tc-RBC studies are more sensitive than both colonoscopy and angiography in detecting intermittent bleeding. Upper endoscopy would be a better choice if an upper GI bleed is suspected because tagged RBC studies are limited in the assessment of the stomach as a result of physiologic splenic activity. In addition to better visualization, upper endoscopy can also provide therapeutic options. One advantage of the tagged RBC study is that it allows for a survey of both the small and large bowel during a much longer time frame. Once the bleed is localized, therapeutic options with interventional radiology can be facilitated because less time is required to find which vessel to treat.