High frequency and dynamic contrast-enhanced ultrasound for treatment follow up of patients with Crohn*s disease.

The evaluation of early treatment response in IBD is often limited to clinical
and biochemical evaluation while endoscopy or other imaging is typically
performed later. Early evaluation of treatment response is of great importance
since it gives clinicians the opportunity to optimize the treatment strategy.
Repeated X-ray examinations pose potential health risks due to radiation while
MRI is resource intensive and less available than ultrasound. Ultrasound
therefore seems to be the most suitable imaging tool during follow up.
Several longitudinal studies have investigated treatment outcome with
ultrasonography. Both increased bowel wall thickness and contrast-enhancement
have been related to the need for surgery, relapse after surgery and monitoring
treatment effect. In a recent study Quaia et al. showed a difference in
relative perfusion three months after treatment initiation between treatment
responders and non-responders. However, this was a cross-sectional study and
therefore did not include data from treatment start or data on bowel wall
thickness. Nylund et al. recently published a pilot study which showed that
patients with treatment failure after one month had increased perfusion and a
thickened proper muscle layer. These results suggest that early findings in
treatment follow-up may give prognostic information that may guide treatment
decisions, but the study was underpowered to look at other outcomes.

The primary objective of this study is to evaluate the sensitivity of high
frequency sonography combined with DCE-US in the follow-up of treatment
efficacy in patients experiencing acute deterioration of Crohn's disease (CD)
started on anti-TNF treatment compared to ileocolonoscopy as the reference
standard.

Single center, prospective observational study with 6 months follow-up

Blood will be drawn four times in six months to measure various inflammatory
markers as part of standard care. Patients will be subjected to four
trans-abdominal ultrasound examinations with contrast enhancement and two
ileocolonoscopies (standard care). Only patients that need treatment in the
frame of their usual care will be included. Trans-abdominal ultrasound is a
safe procedure that uses high frequency sound waves for the visualization of
internal organs. Contrast enhanced ultrasound has a very low risk. Anaphylactic
reactions to Sonovue contrast solution have been reported in less than 1 in
10.000 patients.
Implementation contrast enhanced ultrasound for treatment follow-up in CD
patients may result in a reduced need for ileocolonoscopy and MRI, thereby
reducing costs and the burden for patients. Waiting times for ileocolonoscopy
and MRI are also long whereas ultrasound can be applied on a more regular
basis. Treatment decisions based on ultrasound appearance can be made *on the
spot*, allowing for a point-of-care approach in CD patients.