A Prospective Comparison of 99m Tc-Labeled Polyclonal Human Immunoglobulin and 111 In Granulocytes for Localization of Inflammatory Bowel Disease

There is a need for an easily prepared radiopharmaceutical agent for the detection of inflammation and infection. In a group of 14 patients with inflammatory bowel disease (IBD), the detection of actively involved intestinal segments by nonspecific human polyclonal immunoglobulin (IgG) labeled with 99m Tc was compared with that of 111 In granulocytes. To determine the specificity of 99m Tc-IgG scintigraphy, 8 control patients without clinical indications of intestinal inflammation were examined. 99m Tc-IgG was found in the left colon in 8 and in the right colon in 7 of the 8 controls 4 hours after the injection. At that time of scintigraphy only 4 IBD patients exhibited a more intense accumulation at the site of the intestinal segments with active disease. In contrast, in a randomized comparison with 111 In granulocytes scintigraphy was positive in 11 patients with the latter technique. Moreover, fewer diseased segments were seen in the 4 patients with positive 99m Tc-IgG scintigraphy (6 versus 12 with 111 In granulocytes). In view of the low sensitivity and specificity, it is concluded that 99m Tc-IgG is not suitable for the scintigraphic staging of IBD patients.