Diffusion-weighted MR enterography for evaluating Crohn's disease: how does it add diagnostically to conventional MR...

Area of Science:

• Gastroenterology
• Radiology
• Medical Imaging

Background:

• Crohn's disease (CD) diagnosis relies on imaging techniques.
• Magnetic resonance enterography (MRE) is a standard tool for evaluating CD.
• The added value of diffusion-weighted imaging (DWI) to MRE for CD assessment is not well-established.

Purpose of the Study:

• To determine if DWI enhances the accuracy of conventional MRE in detecting bowel inflammation in patients with suspected CD.
• To assess the impact of DWI on the sensitivity and specificity of MRE for diagnosing active CD.

Main Methods:

• Prospective study of 50 adults with suspected CD undergoing clinical assessment, MRE with DWI (b=900 s/mm²), and ileocolonoscopy.
• MRE and DWI interpretations were blinded.
• Per-segment accuracy was evaluated by comparing MRE findings with endoscopy as the reference standard.

Main Results:

• Conventional MRE + DWI showed higher sensitivity (83%) for bowel inflammation than MRE alone (62%), primarily due to detecting milder inflammation like aphthae and erythema.
• However, specificity decreased significantly with DWI (60% vs. 94%), with numerous false positives.
• DWI findings correlated with higher Crohn's disease endoscopic index of severity scores and deeper ulcers when active inflammation was already seen on MRE.

Conclusions:

• Diffusion-weighted imaging (DWI) without water enema does not improve the detection of bowel inflammation in Crohn's disease when used with conventional MRE.
• DWI may assist in characterizing the severity of inflammation in segments already identified as active by MRE.