Preoperative localization of intermittently bleeding small intestinal tumors using Tc-99m labeled red blood cell scanning. Report of two cases.

Frequent tagged red blood cell scans offer an important diagnostic adjunct to help define a site of intermittent bleeding. Success is based upon scanning at two-to-four-hour intervals. Two patients are presented who experienced intermittent episodes of melena and hematochezia over prolonged periods of time. In each case an extensive diagnostic work-up had been performed on multiple occasions and failed to demonstrate the source. Utilizing a Technetium-99 macroaggregated albumin (Tc-99m) tagged red blood cell scan, an intermittently bleeding lesion within the small bowel was identified in each instance. In order to detect an intermittently bleeding lesion within the small bowel, more frequent scanning intervals are recommended. Due to rapid clearing of tagged red blood cells into the colon from the small-bowel bleeding point, the source may be obscured by longer, routine scanning intervals.