Lecture Objectives

Purpose

Validate the recently developed modified Van Assche index for MRI in patients with perianal Crohn´s disease (CD) receiving tumour necrosis factor (TNF) antagonists.

Conclusion

The modified Van Assche index was responsive to change in patients with perianal CD responding to anti-TNF treatment. However, sensitivity to change was comparable with the original index. Further research is warranted to establish the modified Van Assche index’ clinical value.

Material and methods

A search of medical records identified patients with fistulising perianal CD who had undergone a baseline and follow-up MRI while receiving anti-TNF treatment. Patients were divided in clinical responders and non-responders based on physician’s assessment. MRI-scans were scored using the orignal and modified Van Assche index by two independent radiologists. Discrepant reads were reassessed by a third radiologist. Outcomes were compared between clinical responders and non-responders using a Wilcoxon rank-sum test. Interobserver agreement was assessed using kappa statistics and intraclass correlation coefficients (ICC).

Results

Thirty cases were included (12 female, median age 27 years). Clinical responders (n=16) had a median modified Van Assche index of 9.6 (IQR 5.8-12.7) at baseline and 5.8 (IQR 3.5-8.5) at follow-up (p=0.008). For clinical non-responders (n=14), corresponding scores were 7.7 (IQR 5.8-13.5) versus 8.2 (IQR 5.8-11.5) (p=0.624). Scores obtained with the original Van Assche index significantly dropped between follow-up and baseline MRI scans in clinical responders (13.0 vs. 9.6, p=0.011), whereas no decrease was observed in non-responders (11.5 vs. 11.5, p=0.324). Interobserver agreement ranged from ‘fair’ to ‘substantial’ (k 0.40-0.65) for separate items and was ‘substantial’ for the total index (ICC 0.74).

Lecture Objectives