The Use of Small Bowel Ultrasound to Predict Response to Remicade Induction

Pediatric inflammatory bowel disease (IBD) patients are at increased risk for high ionizing radiation exposure in the assessment of their condition. Small bowel ultrasound (SBUS) is emerging as a well tolerated, non-invasive, radiation free, low cost measure to assess inflammatory bowel disease, and is being used as first-line imaging in Europe. SBUS findings have been shown to correlate with endoscopic findings, and a small number of recent studies have looked at change in bowel wall thickness (BWT), in response to anti-TNF therapy. The use of SBUS to detect response to anti-TNF therapy has not been tested in pediatric patients. In addition, these studies frequently use Crohn's Disease Activity Index (CDAI) as a measure of clinical activity, yet it is known from multiple studies including the SONIC trial that CDAI is not a reliable or accurate measure to predict mucosal healing. A weighted PCDAI will be used instead, which has been shown to perform better than the original PCDAI and is more feasible, especially considering the study spans 14 weeks and scoring items such as height velocity from the full PCDAI will be irrelevant. The goal of this study is to measure bowel wall thickness (BWT) prior to initiating infliximab (IFX 0) and at week 14 and to look at the correlation between change in BWT (delta BWT) with change in clinical disease activity (delta wPCDAI) between these two time points. The research team will measure fecal calprotectin at baseline and at week 14 with stool collected the day prior to the visit using a specimen collection kit given to subjects. The research team will also collect results from routine laboratories (including C-Reactive Protein, Erythrocyte Sedimentation Rate, Complete Blood Count, and Albumin) done before each infusion, and IFX levels and anti-infliximab antibodies (ATI) at week 14 to assess change in biochemical response to infliximab treatment, as well as correlation between these markers with changes in patient reported outcomes (via a wPCDAI questionnaire) and changes in BWT.