Pitfalls of gastrointestinal bleeding studies with 99mTc-labeled RBCs

Abstract

A 52-YEAR-OLD woman presented with a five-day history of dark stools and nausea. Physical examination revealed a blood pressure of 148/106 mm Hg, pulse of 84/rain, and epigastric and right lower quadrant tenderness. Rectal examination demonstrated external hemorrhoids with a strongly positive guiac stool. Her hemoglobin and hematocrit levels were 10.0 (12 to 15 g/dL) and 31.1 (36% to 45%), respectively. Upon admission, a gastrointestinal bleeding study was obtained (Fig 1). Two days later, esophagogastroduodenoscopy revealed a superficial ulceration at the esophagogastric junction. The following day, abdominal CT was obtained for evaluation of the upper abdominal lesion (Fig 2) and perhaps a second contiguous lesion noted during scintigraphy (Fig 3). Based on the scintigraphic and positive CT findings, hepatic arteriography was performed two days later (Fig 4). She was treated conservatively for her ulcer and was discharged in stable condition. Several techniques have appeared in the literature for the preparation of 99mTc-labeled RBCs. 1-3 Unfortunately, the use of these techniques for the evaluation of gastrointestinal bleeding suffers in various degrees from the presence of and, therefore, physiologic interference by 99mTc-pertechnetate. A further refinement of technique, to minimize the presence of unbound technetium, has been reported, 4 and a