Technetium-99m RBC bleeding images in normal subjects: confusion with gastrointestinal bleeding sites.

The normal appearance of a gastrointestinal bleeding study using labeled red blood cells has been discussed frequently, but the actual appearance is not well known. In this atlas article, the authors report on unusual findings in non-bleeding subjects and have tabulated the visualization of various structures. Vascular structures other than the aorta and inferior vena cava were seen in 42 of 48 patients. One or both kidneys were seen in 10 (21%) of 48 patients. The urinary bladder was seen in 23 (48%) of 48 patients, although gastric activity caused by free pertechnetate was never observed.