Grading of Crohn’s disease activity using CT, MRI, US and scintigraphy: a meta-analysis

PURPOSE: To assess the grading of Crohn's disease activity using CT, MRI, US and scintigraphy. MATERIALS AND METHODS: MEDLINE, EMBASE and Cochrane databases were searched (January 1983-March 2014) for studies evaluating CT, MRI, US and scintigraphy in grading Crohn's disease activity compared to endoscopy, biopsies or intraoperative findings. Two independent reviewers assessed the data. Three-by-three tables (none, mild, frank disease) were constructed for all studies, and estimates of accurate, over- and under-grading were calculated/summarized by fixed or random effects models. RESULTS: Our search yielded 9356 articles, 19 of which were included. Per-patient data showed accurate grading values for CT, MRI, US and scintigraphy of 86% (95% CI: 75-93%), 84% (95% CI: 67-93%), 44% (95% CI: 28-61%) and 40% (95% CI: 16-70%), respectively. In the per-patient analysis, CT and MRI showed similar accurate grading estimates (P = 0.8). Per-segment data showed accurate grading values for CT and scintigraphy of 87% (95% CI: 77-93%) and 86% (95% CI: 80-91%), respectively. MRI and US showed grading accuracies of 67-82% and 56-75%, respectively. CONCLUSIONS: CT and MRI showed comparable high accurate grading estimates in the per-patient analysis. Results for US and scintigraphy were inconsistent, and limited data were available. KEY POINTS: • CT and MRI have comparable high accuracy in grading Crohn's disease. • Data on US and scintigraphy is inconsistent and limited. • MRI is preferable over CT as it lacks ionizing radiation exposure.