Repeat planar white cell scanning to monitor short-term therapy of active inflammatory bowel disease: a methodological study and comparison with clinical scores and novel inflammatory markers.

Objectives: Radiolabelled white cell scans provide non-invasive quantification of inflammatory activity. Clinical activity scores measure severity of disease but are partly subjective. White cell scans may provide a suitable method of monitoring the treatment response of active inflammatory bowel disease.

Methods: Ten subjects with active ulcerative colitis and 13 subjects with active Crohn's disease were recruited. White cell scans were carried out before and 2 weeks after treatment. Prior to each scan, activity scores for ulcerative colitis or Crohn's disease were calculated and serum and faecal tumour necrosis factor-alpha and calprotectin measured. White cell scan activity at 1 h was calculated by using a validated visual grading system.

Results: Following anti-inflammatory treatment, 70% of white cell scans improved, 17% remained unchanged and 13% deteriorated. In the ulcerative colitis subgroup subjects there was modest agreement for change in scan score and activity scores. In the Crohn's disease subjects there was better agreement between change of white cell scan score and clinical scores. Planar white cell scans correlated with the van Hees activity index (r=0.68, P=0.002) and faecal calprotectin (r=0.58, P=0.0003). Changes in planar white cell scans correlated with changes in serum calprotectin (r=0.45, P=0.05).

Conclusion: Non-invasive white cell scanning is a feasible and objective method to monitor the anti-inflammatory efficacy of treatments for active inflammatory bowel disease.