Magnetic resonance imaging of the effects of infliximab on perianal fistulizing Crohn's disease.
OBJECTIVE
Although the clinical efficacy of infliximab as measured by closure of fistulas in Crohn's disease has been demonstrated, its influence on the inflammatory changes in the fistula tracks is less clear. The aim of the present study was to assess the behavior of perianal fistulas before and after infliximab treatment.


METHODS
Magnetic resonance imaging (MRI) and clinical evaluation were performed in a total of 18 patients before and after treatment with infliximab. An MRI-based score of perianal Crohn's disease severity was developed using both criteria of local extension of fistulas (complexity, supralavetoric extension, relation to the sphincters and of active inflammation (T2 hyperintensity, presence of cavities/abscesses, and rectal wall involvement).


RESULTS
The MRI score was reliable in assessing the fistula tracks, with a good interobserver concordance (p < 0.001). Fistula tracks with signs of active inflammation were found in all 18 patients at baseline and collections in seven. After short-term infliximab treatment, active tracks persisted in eight of 11 patients who had clinically responded to infliximab. After long-term (46 wk) infliximab therapy, MRI signs of active track inflammation had resolved in three of six patients.


CONCLUSIONS
We have developed an MRI-based score of perianal Crohn's disease severity to assess the anatomical evolution of Crohn's fistulas. Our study demonstrates that despite closure of draining external orifices after infliximab therapy, fistula tracks persist with varying degrees of residual inflammation, which may cause recurrent fistulas and pelvic abscesses. Whether complete fistula fibrosis occurs over time with repeated infliximab infusions needs further study.
Van Assche
Gert
G
Division of Gastroenterology, University Hospital, University of Leuven, Belgium.
Vanbeckevoort
Dirk
D
Bielen
Didier
D
Coremans
Georges
G
Aerden
Isolde
I
Noman
Maya
M
D'Hoore
Andre
A
Penninckx
Freddy
F
Marchal
Guy
G
Cornillie
Freddy
F
Rutgeerts
Paul
P
D000328:Adult; D000911:Antibodies, Monoclonal / Q000627:therapeutic use*; D003424:Crohn Disease / Q000150:complications / Q000188:drug therapy* / Q000473:pathology; D005260:Female; D005765:Gastrointestinal Agents / Q000627:therapeutic use*; D006801:Humans; D000069285:Infliximab; D008279:Magnetic Resonance Imaging; D008297:Male; D011446:Prospective Studies; D012003:Rectal Fistula / Q000209:etiology* / Q000473:pathology; D012007:Rectum / Q000473:pathology
D000911:Antibodies, Monoclonal; D005765:Gastrointestinal Agents; D000069285:Infliximab