Assessment of disease activity and localization in inflammatory bowel disease using 99mTc‐labelled leucocytes

Disease activity and regional extent of disease was studied in 20 patients with inflammatory bowel disease (13 with Crohn's disease and seven with ulcerative colitis). Autologous white cells from patients and controls were labelled with 99mTc-stannous colloid, reinjected, and the faecal excretion of the labelled leucocytes was assessed over 48 h. In patients with Crohn's disease, the faecal excretion correlated with severity of disease as judged by the Harvey-Bradshaw index. In 18 of the 20 patients the extent of the inflammatory bowel disease as indicated by the scan image corresponded with the radiological and colonoscopic findings. The 99mTc-stannous colloid label has advantages over indium-111 and the faecal excretion of labelled leucocytes has potential as a simple, objective measure of disease activity.