Tc-99m antigranulocyte monoclonal antibody imaging for the detection and assessment of inflammatory bowel disease newly diagnosed by colonoscopy in children

Objective. This prospective study evaluated a Tc-99m antigranulocyte monocl onal antibody Fab' imaging agent (Sulesomab) in children with inflammatory bowel disease (IBD) newly diagnosed by colonoscopy. Materials and methods. Ten children (4 boys, 6 girls; mean age 14 years) wi th newly diagnosed Crohn's disease (n = 6) or ulcerative colitis (n = 4) we re studied. Colonoscopy was performed in all of these patients. Within 24 h after colonoscopy, they underwent scintigraphy with Tc-99m-Sulesomab. Abdo minal/ pelvic images were acquired at 30 min (planar) and 2-4 h (planar and SPECT) after injection of Sulesomab. Eighty bowel segments were evaluated semi-quantitatively by the investigators, using these three sets of images. The Pediatric Disease Activity (PDA) was correlated with the erythrocyte s edimentation rate (ESR), white blood cell (WBC) count, albumin, Kirschner's score, the Sulesomab bowel segment with maximum uptake, and the sum of Sul esomab score in each segment. Results. The median PDA score was 26 (range 12.5-40). Three children had no rmal ESR and six normal WBC counts. All patients had at least one positive mucosal biopsy for IBD. While using the Kirschner's scale, the maximal seve rity of colonoscopy findings was graded as none (n = 2), mild (n = 4), mode rate (n = 3), or severe (n = 1). Of the 59 segments evaluated with endoscop y, 35 were found to be endoscopically abnormal. The planar images identifie d 17 of these abnormal segments and the SPECT images 20. Nine of these ten children had abnormal bowel uptake by scintigraphy. Thus, the sensitivity o f Sulesomab per patient was 90% and per bowel segment 57%. The correlation coefficient between the scintigraphic score for the segment with the Suleso mab maximum activity and the PDA was 0.3 (P = 0.41). Conclusion. In pediatric IBD assessment, planar imaging with Sulesomab did not prove very sensitive in detecting inflammation in each bowel segment. H owever, SPECT detected the presence of inflammation in the majority of pati ents. A trial comparing Tc-99m-HmPAO-WBC with Sulesomab in a large number o f patients is required.