111In-Oxine-labelled autologous leucocytes in inflammatory bowel disease: New scintigraphic activity index

The usefulness of scintigraphy with ¹¹¹In-oxinelabelled autologous leucocytes was investigated in 27 patients with inflamatory bowel disease (IBD): 16 with ulcerative colitis and 11 with Crohn's disease. Scans were performed 2–4 h (early scan) and at 24 h (late scan) after leucocyte reinjection. No false-negative results occurred in the early scan; however, in the late scan, 2 patients with Crohn's disease had a normal scintigram. A new index of activity (I_l) based on the number and relative activity of abnormal ¹¹¹In-leucocyte zones was used for scan quantitation. All patients with clinically active IBD had I_l2. The scintigraphic index showed a significant correlation with the Harvey clinical index, especially in patients with ulcerative colitis. Our results suggest that an early scan (2–4 h) provides useful information in cases of IBD, and that I_l2 is indicative of the degree of disease activity in such patients.