Combined Dynamic MR enterography and colonography in pediatric patients with suspected IBD

Inflammatory bowel disease (IBD) primarily comprises ulcerative colitis (UC)
and Crohn's disease (CD). These disorders have distinct pathologic and clinical
characteristics. Because there is a difference in treatment strategies and
clinical course of both diseases, it is important to establish the correct
diagnosis when a patient is suspected of IBD. This is done by a complete
work-up comprised of clinical history, physical examination, laboratory
studies, endoscopic findings, histological interpretation of mucosal biopsy
specimens and imaging studies. Magnetic resonance imaging (MRI) is used for
assessing disease activity of the small bowel. Abdominal MR-imaging using
luminal and intravenous contrast medium combines transmural and
extra-intestinal evaluation and can accurately show presence of disease.
Gadolinium is an extracellular contrast agent that rapidly passes from the
vasculature into the extravascular-extracellular space and in that way produces
parenchymal enhancement, which is associated with disease activity. Dynamic
contrast enhanced MRI (DCE-MRI) is a method to objectively determine the
enhancement after administration of intravenous contrast medium. In DCE-MRI
images are acquired during the delivery of contrast in the tissue of interest,
highlighting the dynamic response of the tissue to the inflow of blood.
Analysis of the time-dependent changes in signal intensity by DCE-MRI can
provide valuable information about disease activity. One recent study by
Horsthuis et al. has shown that DCE-MRI can be used to determine disease
activity in perianal fistulizing CD, as correlations were found between
clinically active disease and more quickly enhancing pixels, meaning a stronger
vascularisation, in patients with perianal fistulizing CD. We expect this also
to be the case in patients with active luminal CD and UC because in these
patients there is also an increased degree of vascularity in the bowel due to
the inflammatory reaction. We combine DCE-MRI enterography and colonography in
the same session to assess the enhancement of the bowel wall and thus give
objective measurements of disease activity thereby aiding in the diagnosis of
UC or CD in pediatric patients.

The primary objective is to assess the feasibility and accuracy of dynamic
contrast enhanced MRI in diagnosing UC or CD in children as compared to
endoscopy and abdominal ultrasound.
The secondary objective is to assess the feasibility of dynamic contrast
enhanced MRI in grading disease activity in UC or CD in pediatric patients.

We want to conduct a prospective observational study. All patients with
clinical suspected IBD will undergo a MRI scan with oral and intravenous
contrast medium and gastroscopy and ileocolonoscopy under general anesthesia as
part of their clinical routine.
The Pediatric Crohn*s Disease activity index, and the Pediatric Ulcerative
Colitis activity index will be calculated at the outpatient clinics.

Patients will undergo an ileocolonoscopy and gastroscopy under general
anesthesia and MRI with oral and intravenous contrast medium scan as part of
their clinical investigation. For this study, an extra dynamic sequence will be
added to the MRI scan (scanning time will be prolonged for 10 minutes, total
scanning time will be 50 minutes).
For this preparation patients will be asked to come two hours earlier and drink
an additional contrast medium for the distension of the colon (400 ml extra) .
Also an additional abdominal utrasound will be performed on the same day or the
day before the endoscopy or the same day as the MRI scan so no additional visit
to the hospital is necessary. No extra preparation is required for the
ultrasound.