TC-99(M) HMPAO-LABELED LEUKOCYTE IMAGING IN CROHNS-DISEASE - A SUBTRACTION TECHNIQUE FOR THE QUANTIFICATION OF DISEASE-ACTIVITY

A new technique for the quantitative analysis of labelled leucocyte im ages from patients with inflammatory bowel disease is described. The m ethod involves the computer generation of a 'background' image which, after appropriate registration, is subtracted from the patients image to leave a residue which represents abnormal uptake in the bowel. Quan tification of the residual activity yields a scan score which can be r elated to the level of disease activity in patients with Crohn's disea se. In 54 investigations on 33 patients the scan scores correctly agre ed with a clinical assessment of disease activity in 16 of 20 cases wi th inactive disease and 32 out of 34 cases with active disease. Most o f the discrepancies reflected inaccuracies in the clinical assessment of activity rather than shortcomings of the imaging technique.