Unusually Intense Delayed Colon Uptake of Tc-99m Exametazime Leukocytes in Ulcerative Colitis Operated Patient

The authors report an unusual pattern of intense delayed colon uptake of Tc-99m exametazime leukocytes in ulcerative colitis. Two years earlier, the patient underwent a sigmoid resection with a lateroterminal descending rectum anastomosis because of pseudopoliposis and sigmoid colon stenosis. Despite immunosuppressive and steroid therapy, the patient experienced abdominal pain and mucinous diarrhea. A leukocytes scan showed intense colon uptake in the 2, 4, and 18 hour frames. Colonoscopy and histology confirmed the diagnosis of pancolitis. The delayed colon image can either be explained by later leukocyte migration from an exchangeable reservoir or specific tracer uptake due to elution, probably enhanced by descending colon spasm.