Abnormal Bladder Mimicking Proctitis on Tc-99m HMPAO Leucocytes Imaging for Inflammatory Bowel Disease

摘要

Radio-labeled leukocyte imaging is a routine procedure for assessing the activity and distribution of inflammatory bowel disease (IBD). Because of the well known advantages of Tc-99m over In-111 such as low radiation, better imaging characteristics, localization of disease to specific bowel segments, especially identification of small bowel disease, easy availability, and cost-effectiveness, Tc-99m HMPAO-leukocyte scintigraphy is preferred in patients with suspected bowel inflammation. Bowel uptake of leukocytes, however, is nonspecific and may be positive in a wide variety of other conditions including infection, vasculitis, neoplasm, and graft versus host disease. Nonspecific bowel activity, not seen on In-Ill leukocyte studies, may also give rise to a mistaken diagnosis of IBD. The normal distribution of Tc-99m labeled leukocytes gives rise to urinary and rarely gallbladder activity, both of which are the result of the excretion of secondary hydrophilic complexes of Tc-99m HMPAO. We report a case where abnormalbladder shape mimicked active proctitis on Tc-99m HMPAO leukocyte imaging for IBD.