The Role of Small Bowel Ultrasound in Initiation of Infliximab in Crohn's Disease Patients

Change in bowel wall thickness as measured on small bowel ultrasound from ultrasound performed on week 0 to ultrasound performed at week 54. Small Bowel Ultrasound will be performed by a single radiologist using an Acuson S2000 machine with 6 MHz convex and 9 MHz linear array transducers (Siemens, Germany). Participants will be asked to not eat for at least 8 hours prior to the ultrasound, and to drink 500ml of a fluid of their choice just prior to the SBUS, for bowel distension and better visualization. Bowel wall thickness (BWT), the length of any segment of thickened bowel wall >3mm, hyperemia using doppler, and the presence of free fluid, stricture, intestinal dilation, or enlarged lymph nodes will be documented.

Univariate analyses will be performed to determine the association between bowel wall thickness on SBUS, and delta BWT (change in bowel wall thickness week 0 to week 14) and presence of remission at week 54

Change in level of stool calprotectin (lab) between week 0 and week 54. Stool will be collected within 24 hours of infusion and performed at our outpatient lab and analyzed by ELISA.

Univariate analyses will be performed to determine the association between calprotectin level, delta calprotectin level (change in calprotectin level week 0 to week 14) and presence of remission at week 54.