The greatest value of this procedure relates to acute lower GI bleeding, that is to say below the ligament of Treitz. Upper GI bleeding does not highly benefit diagnostically with the information provided by scintigraphy. In this regard, endoscopic procedures are more appropiate to localize and even implement therapy. Nonetheless, it is important to be aware of this alternative method, when transit time from stomach to the bowel is rapid, which may limit the yield of endoscopy or active bleeding may occult the site where it is coming from. In order to detect bleeding it has to be over 0.05 to 0.1 ml/min, compared to angiography whose limit is around 1 ml/min. Therefore, scintigraphy is of no utility in chronic GI bleeding.

            Sensitivity and specificity are approximately near  90%. False negatives are seen in small lesions, intermittent bleeding. False positives may be due to free 99mTc in the GI lumen, hemangiomas, renal activity during excretion, vascularized tumors, aneurysm, accessory spleen, renal transplant, etc. Some authors suggest that angiography should be performed after scintigraphy only if the latter is abnormal. Likewise, that anterograde or retrograde blood peristalsis hinders the exact localization place in  scintigraphy.

                      -  Angiodysplasia

                      -  Diverticula

                      -  Gastrointestinal Tumors

                      -  Gastrointestinal polips

                      -  Ischemic Colitis

1  Allan O. Santos, Elba C. S. C. Etchebehere, P. Garcia Alonso y Edwaldo E. Camargo. HEMORRAGIAS DIGESTIVAS , p: 249-257 in: Medicina Nuclear Aplicaciones Clínicas. Eds: I. Carrio - P. González. Editorial Masson, Barcelona España, 2003.

2  Patrick V. Ford et al. Procedure Guideline for Gastrointestinal Bleeding and Meckel’s Diverticulum Scintigraphy 1.0 SOCIETY OF NUCLEAR MEDICINE PROCEDURE GUIDELINES MANUAL 2001-2002: 41-48.