Gastrointestinal Bleeding Scintigraphy

Michael A. McDonald, MD, PhD; Harvey A. Ziessman, MD


Appl Radiol. 2016;45(5):19-22. 

In This Article


A major limitation of RBC scintigraphy is that it may not provide adequate information for unequivocal localization of the site of GIB. Subtraction scintigraphy when used in conjunction with conventional RBC imaging has been shown to improve diagnostic utility by removal of background superimposed on a bleed; improving image contrast and potentially reducing false-positive studies.[13] Combining functional SPECT data with CT (or MRI) via software co-registration of images or image acquisition on dedicated SPECT/CT instrumentation can increase contrast resolution by 10–15% facilitating bleeding source localization by providing accurate anatomical information about the site of 99mTc RBC accumulation.[14] However, software fusion of images acquired separately with different devices can lead to inaccuracies in image registration. Imaging with integrated SPECT/CT instrumentation is limited by the time needed to acquire tomographic images and by constraints imposed by the external dimensions of accessory equipment (e.g., ventilators, etc.).