Gastroenterology ·
Non-contrast MRI shows high agreement with contrast MRI for Crohn’s fistulas
A retrospective study of 145 patients with Crohn’s disease compared pelvic MRI without contrast against contrast-enhanced MRI for perianal fistulas and abscesses. Non-contrast MRI performed well for detecting index fistulas, while contrast-enhanced imaging added value in assessing complex disease, including secondary tracts.
- Non-contrast MRI detected index fistulas with 95% accuracy.
- Abscess detection sensitivity was 77%.
- Contrast-enhanced MRI added value for complex disease.
- Retrospective study used contrast MRI as the reference.
Researchers retrospectively studied 145 patients with Crohn’s disease who underwent pelvic MRI between October 2021 and December 2022. Two observers assessed images in separate sessions, comparing non-contrast MRI (T2-weighted, diffusion-weighted and pre-contrast T1-weighted imaging) with contrast-enhanced MRI, which also included post-contrast T1-weighted imaging. Contrast-enhanced MRI served as the reference standard.
Non-contrast MRI detected an index fistula in 115 patients, compared with 117 on contrast-enhanced MRI. For index fistula detection, non-contrast MRI had 96% sensitivity, 93% specificity and 95% accuracy. Abscesses were identified in 53 patients (37%) on non-contrast MRI and 63 (43%) on contrast-enhanced MRI; sensitivity for abscess detection was 77%, with 95% specificity and 87% accuracy. Agreement between methods varied, and contrast-enhanced imaging provided added value for evaluating complex disease, including secondary fistulas and tracts.
The findings suggest non-contrast MRI may be a reasonable alternative for detecting and grading perianal fistulas when contrast cannot be used or an abbreviated examination is being considered. This was a retrospective study, and performance was measured against contrast-enhanced MRI rather than an independent reference standard; non-contrast imaging was less reliable for some features of complex disease.
In practice
For patients with Crohn’s disease undergoing evaluation for perianal fistulas, non-contrast pelvic MRI may be considered as an imaging option when contrast cannot be administered or an abbreviated examination is sought: it showed high accuracy for index fistula detection in this study. The evidence does not establish equivalence for all disease features. Contrast-enhanced MRI identified more abscesses and added value in complex disease, particularly secondary fistulas and tracts. These results come from a retrospective study that used contrast-enhanced MRI as the reference standard.
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Journal of Crohn's and Colitis: Value of non-contrast magnetic resonance imaging for diagnosis of perianal fistulas in Crohn’s disease ↗This is an automated AI-condensed summary that has not yet been reviewed by an editor. Always consult the full item at the original source.