Role of Hybrid SPECT/CT in combination with 99mTc-labeled RBC dynamic planar scintigraphy for acute non-variceal gastrointestinal bleeding: Our experience

Objectives To present our experience with Hybrid SPECT/CT role in combination with 99mTc-labeled RBC planar scintigraphy in the outcomes of acute non-variceal gastrointestinal (GIB) bleeding.

Methods Between July 2011 and October 2014, 48 TC-99m labeled RBC scintigraphy, along with Hybrid SPECT/CT performed on 47 patients suspected of acute non-variceal GI bleed were retrospectively analyzed. Scintigraphy was considered positive if there was a focus of increased activity that changes in location, increased in intensity over time. If the scintigraphy finding was equivocal/probable, then SPECT/CT was performed, at the discretion of the interpreting physician. Based on the results,care pathway could be mesenteric angiography, endoscopy/colonoscopy, surgery or conservative management.

Results Total of 28 studies were positive for acute bleeding with accurate localization, by using a combination of planar and Spect/CT. 22 patients had mesenteric angiography, with only 3 positive cases and 1 was followed by surgery. 6 patients had endoscopy/colonoscopy, with only 3 positive cases. 20 studies which were read as probable/ equivocal for an acute bleed were confidently interpreted as definitely present or absent on the SPECT/CT. All the negative cases were conservatively managed. Aside from increased accuracy in localization, the other advantages include ruling out equivocal cases so as to aid in management. However, the potential disadvantages include misregistration, false localization due to strong peristaltic and antiperistaltic movements within the lumen pushing the Red blood cells from the bleeding site to another location , the additional time to acquire images, and slow rate of bleed in some cases that is not sensitive to catheter angiogram.

Conclusions SPECT/CT has the ability to improve the identification and localization of GI bleeding, However this modality has potential disadvantages that may affect the outcome in certain cases