Sonographic measurement of thickened bowel wall segments as a quantitative parameter for activity in inflammatory bowel disease

Inflammatory bowel disease (IBD) is associated with morphological changes of the bowel wall that can be visualized by abdominal ultrasound (US). This method is a tool to detect the extent of bowel wall thickening and the length of involved segments. The purpose of this study was to determine the value of sonographic measurement of inflamed bowel wall segments as a quantitative parameter for disease activity. 137 patients with Crohn's disease (CD) and 32 patients with ulcerative colitis (UC) were included in the present study. A total 356 US examinations were performed within a one-year period. In a segment-by-segment analysis we determined the >>volume of inflamed bowel wall<< (VIB) by measuring wall thickness and longitudinal extent of pathologically altered bowel segments. VIB was used as a quantitative parameter for disease activity based on sonomorphological findings. At the same time the following parameters were also determined: CD activity index (CDAI) in patients with CD, clinical activity index (CAI) in patients with UC, erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP). We found no relevant correlation between VIB and biochemical indices of inflammation (ESR, CRP) and between VIB and clinical activity of IBD (CDAI, CAI). All correlation coefficients were below 0.5. It can be concluded that the extent of inflammatory changes of the bowel wall detected by US is not strictly associated with clinical activity and laboratory parameters of inflammation.