Mesenteric lymph nodes in MR enterography: are they reliable followers of bowel in active Crohn’s disease?

Objectives To demonstrate magnetic resonance enterography (MRE) features of mesenteric lymph nodes (LN) in patients with Crohn’s disease (CD) and investigate whether they follow enhancement or apparent diffusion coefficient (ADC) parameters of bowel. Methods This study was approved by the institutional review board. A total of 788 MREs from patients with CD were retrospectively reviewed. Eighty-eight patients, aged 16-66 years, including 59 active cases, were enrolled based on inclusion criteria. In each MRE, two segments (normal and abnormal) and two LNs (regional and non-regional) were independently suggested, consensually chosen, and analyzed by two radiologists. Signal-to-noise (SNR) and contrast-to-noise (CNR) ratios were calculated to assess signal intensities (SI) at 30, 60 and 180 s after contrast administration, as well as slope of enhancement (SOE). Enhancement parameters and ADC values were compared. Results Regional LNs showed significantly higher SI 30 , SI 60 and SI 180 (CNR&SNR) and lower ADC values in active vs. inactive groups (all p