This study will examine whether delivery of high dose steroids, directly into the inflamed bowel via its arterial blood supply, will be better for treating uncontrolled flares of inflammatory bowel disease in patients compared to conventional intra-venous or oral administration of this drug. Patients aged 4-25 years of age will be recruited.

In this study, the Investigator hopes to also learn how this directed steroid delivery during an active flare will improve patient symptoms as well as the appearance of inflamed segments of bowel determined by imaging or biopsy (i.e. at the time of endoscopy). Additional data will determine how the blood vessels in the bowel affect, and potentially even drive the mechanisms, of inflammatory bowel disease.

Inclusion Criteria:

• Patients with newly diagnosis of inflammatory bowel disease (IBD) or patients who have an established diagnosis of IBD and are experiencing an acute flare which is not being controlled with first line therapy
• Patients present with typical IBD symptoms which will include, but are not limited to, abdominal pain, loss of appetite, rectal bleeding, diarrhea, obstruction, or passage of mucus.
• Patients referred by the GI team.
• Patients (or guardians/parents) must be able and willing to give consent (or assent where applicable) and be able to attend all study visits.

Exclusion Criteria:

• Patients with MR unsafe metallic implants that will not be able to undergo the MRI portion of the study.
• Patients with renal function impairment (GFR < 45 mL/min) preventing contrast administration.
• Patients with contrast allergy.