The Role of 99M Tc-Rbc Scintigraphy in Lower Gastrointestinal Hemorrhage

Given the controversy surrounding the use of 99m Tc-RBC scintigraphy (TRBCS) in lower gastrointestinal hemorrhage (LGIH), we examined how often it was performed and whether it led to specific therapy. We performed a retrospective cohort study of 565 admissions with a primary diagnosis of LGIH. We obtained detailed clinical data on all subjects, focusing in particular on outcomes after TRBCS. 199 TRBCS studies were performed during 166 patient admissions (a patient admission was defined as an incident LGIH episode in a single patient). Of the 166 patient admissions in which TRBCS was performed, the scan was positive in approximately half (84/166; 51%); if TRBCS themselves were considered, they were positive 42% (84/199) of the time. Of the 84 admissions with a positive TRBCS, angiography was performed 54 times. Among this group, angiography revealed bleeding in only 20 patients (11 patients underwent embolization and 9 had hemostatic therapy). Out of 64 patients with a positive TRBCS who underwent colonoscopy, only 3 patients underwent endoscopic hemostatic therapy. Surgery was performed in 20 patients after a positive TRBCS (including in 17/54 patients after angiogram) and hemostasis was achieved in 16. Angiography, surgery and therapeutic colonoscopy were more commonly performed after positive than after a negative TRBCS. Patients who underwent angiography within 4 h of a positive TRBCS were neither more likely to have active bleeding found nor to undergo successful embolization. Not all patients with a positive TRBCS underwent angiography, and an abnormal TRBCS did not appear to predict successful angiographic therapy; further, a positive TRBCS was not predictive of subsequent definitive therapy. Because TRBCS appears to be followed up inconsistently, the data bring into question its routine use in clinical practice, and specifically raise the possibility that it is overused in patients with LGIH.