Crohn's disease is characterized by inflammatory lesions in the gastrointestinal tract,
most commonly in the terminal ileum and colon.
The lesions are usually transmural,
which can lead to complications like stenoses,
fistulas and abscesses.
While most patients first present with inflammation only,
about two thirds of patients will develop complications within 10 years .
We analized:
1.
Localization of the disease
2.
Bowel thickness.
The normal bowel wall has a thickness of 1-3 mm. A common categorization is 3-5 mm for mild thickening,
5-7 mm for moderate thickening and > 7 mm for marked thickening of the bowel wall (Fig.
1)
3.
Enhancement of the bowel wall (Fig.2,
3).
Enhancement of the bowel wall can be categorized in one of the following patterns:
· Homogeneous
· Mucosal
· Layered
4.
Loss of haustration (Fig.
4).
When the colon is involved in Crohn's disease a decrease of haustral folds can be seen.
A complete loss of haustration results in a smooth surface.
5.
Comb sign (Fig.5,
6,
7,
8).
Increased vascularity of the mesentery is seen in active inflammation.
6.
Skip lesions (Fig.9,
10).
Skip lesions and patchy inflammation are a typical finding in Crohn's disease.
7.
Stenosis (Fig.
11,
12,
13 14).
Stenosis can present as bowel wall thickening combined with lumen narrowing.
8.
Fistula (Fig.
15,
16 17)
All patients had chronic inflammatory bowel disease and were treated with biologic agents.
In 130 patients the MRI examination showed no disease activity; in 63 patients the presence of a recovery of the disease and in 28 patients showed the presence of fibrotic strictures at the localization of the disease.
6 patients had a fistula between the small intestin and the bladder.
In addition DWI sequences allowed to identify the possible localization of the acute diseas and the associated lynphadenopathies