Diffusion-weighted imaging and apparent diffusion coefficient values for evaluating terminal ileitis in patients with Crohn's disease.

Evandra Durayski,Diego Hermindo Roman,Bruno Hochhegger,Edson Marchiori,Matteo Baldisserotto,Guilherme Watte,Gabriel Sartori Pacini,Marta Brenner Machado

doi:10.1590/0100-3984.2019.0011

Abstract

Objective:To determine the accuracy of diffusion-weighted imaging (DWI) in identifying terminal ileitis in patients with Crohn’s disease.Materials and Methods:This was a retrospective study of 38 consecutive patients with Crohn’s disease who underwent magnetic resonance enterography with DWI in a 3.0 T scanner. The patients were divided into two groups, on the basis of colonoscopy and biopsy findings: active inflammation; and inactive disease. Apparent diffusion coefficient (ADC) values were determined, as were the magnetic resonance index of activity (MaRIA) and the Clermont score.Results:Of the 38 patients evaluated, 18 (47%) had active inflammation. The patients with active inflammation showed greater restricted diffusion, more pronounced mucosal edema, greater wall thickening, a higher MaRIA, and a higher Clermont score than did those with inactive disease. The level of interobserver agreement (intraclass correlation coefficient) was excellent for the MaRIA and the Clermont score, whereas it was substantial for the ADC values. For identifying colonoscopy-proven inflammation, the best ADC cut-off point was 2.1 × 10−3 mm2/s, which had a sensitivity of 88.8% and a specificity of 95.0%, whereas DWI presented an overall accuracy of 89.4%, with a sensitivity of 88.9% and a specificity of 90.0%.Conclusion:Visual analysis of the DWI sequence has good accuracy in detecting terminal ileitis in patients with Crohn’s disease. In addition, low ADC values have good sensitivity for detecting colonoscopy-proven inflammation.

Highlights

Crohn’s disease is an idiopathic inflammatory bowel disease that primarily affects the terminal ileum
For identifying colonoscopy-proven inflammation, the best Apparent diffusion coefficient (ADC) cut-off point was 2.1 × 10−3 mm2/s, which had a sensitivity of 88.8% and a specificity of 95.0%, whereas diffusion-weighted imaging (DWI) presented an overall accuracy of 89.4%, with a sensitivity of 88.9% and a specificity of 90.0%
The inactive disease group consisted of patients diagnosed with Crohn’s disease who underwent colonoscopy and a subsequent biopsy that showed no signs of acute inflammation in the terminal ileum

Summary

INTRODUCTION

Crohn’s disease is an idiopathic inflammatory bowel disease that primarily affects the terminal ileum. Diffusion-weighted imaging (DWI) sequences for MRE do not use intravenous contrast agents and allow the evaluation of the movement (Brownian motion) of water molecules in tissues. Studies have shown that restricted diffusion in the wall of the intestine correlates with inflammation. Diffusion has the potential to be a biomarker of intestinal inflammation in Crohn’s disease[3]. There have been few studies evaluating the potential of ADC values to identify inflammation[6]. Such studies have involved small numbers of patients and have not correlated their results with pathology[7]. The present study aims to determine the accuracy of DWI in identifying signs of terminal ileitis in patients with Crohn’s disease

MATERIALS AND METHODS

RESULTS

DISCUSSION