TC-99M-LABELED RED-BLOOD-CELL SCANS IN THE INVESTIGATION OF GASTROINTESTINAL-BLEEDING

PURPOSE: Technetium-99m-labeled red blood cell scans (Tc39m RBC scan) are recommended to confirm gastrointestinal (GI) bleeding. It is contr oversial whether these scans are sufficient to localize the site of bl eeding. This study evaluated the efficacy of RBC scans in confirming a nd localizing GI bleeding. Our hypothesis was that these scans were ef fective in localizing GI bleeding if positive within the continuous ph ase of imaging. METHOD: Tc93m RBC scans were performed on a total of 8 0 patients over a four-year period to localize GI bleeding (59 male, 2 1 female; age range 6-88 (mean, 48) years). Films of 75 of the 80 pati ents were reread by a nuclear medicine physician who was blinded to th e original reading and identity and history of the patient. Results of scans were compared with confirmatory studies. RESULTS: A total of 21 patients had positive scans (28 percent). Of these, the site of bleed ing in 16 of 21 patients (76 percent) was confirmed by angiography (4/ 16), endoscopy (10/16), surgery (10/16), or a combination of these. In 14 of the 16 confirmed studies (88 percent), RBC scan correctly local ized site of bleeding by our rigid definition. In six patients (4 not confirmed, 2 erroneously localized), scans were positive only at great er than 15 hours. Ten of the 14 correctly localized studies and none o f the incorrectly localized studies were positive in the continuous ph ase of imaging. CONCLUSION: Tc39m RBC scan is effective in localizing GI bleeding when positive within the continuous phase of imaging. In t his population supplemental angiography or endoscopy for the purpose o f localization would seem unnecessary.