Diffusion-weighted imaging for evaluating inflammatory activity in Crohn's disease: comparison with histopathology, conventional MRI activity scores, and faecal calprotectin.

Abstract

PURPOSE:

To evaluate whether the extent of enteric diffusion-weighted imaging (DWI) signal abnormality reflects inflammatory burden in Crohn's disease (CD), and to compare qualitative and quantitative grading.

METHODS:

69 CD patients (35 male, age 16-78) undergoing MR enterography with DWI (MRE-D) and the same-day faecal calprotectin (cohort 1) were supplemented by 29 patients (19 male, age 16-70) undergoing MRE-D and terminal ileal biopsy (cohort 2). Global (cohort 1) and terminal ileal (cohort 2) DWI signal was graded (0 to 3) by 2 radiologists and segmental apparent diffusion coefficient (ADC) calculated. Data were compared to calprotectin and a validated MRI activity score [MEGS] (cohort 1), and a histopathological activity score (eAIS) (cohort 2) using nonparametric testing and rank correlation.

RESULTS:

Patients with normal (grades 0 and 1) DWI signal had lower calprotectin and MEGS than those with abnormal signal (grades 2 and 3) (160 vs. 492 μg/l, p = 0.0004, and 3.3 vs. 21, p < 0.0001), respectively. Calprotectin was lower if abnormal DWI affected <10 cm of small bowel compared to diffuse small and large bowel abnormality (236 vs. 571 μg, p = 0.009). The sensitivity and specificity for active disease (calprotectin > 120 μg/l) were 83% and 52%, respectively. There was a negative correlation between ileal MEGS and ADC (r = -0.41, p = 0.017). There was no significant difference in eAIS between qualitative DWI scores (p = 0.42). Mean ADC was not different in those with and without histological inflammation (2077 vs. 1622 × 10-6mm2/s, p = 0.10) CONCLUSIONS: Qualitative grading of DWI signal has utility in defining the burden of CD activity. Quantitative ADC measurements have poor discriminatory ability for segmental disease activity.

• Authors: D A Pendsé, J C Makanyanga, A A Plumb, G Bhatnagar, D Atkinson, Manuel Rodriguez-Justo, S Halligan, S A Taylor
• Journal: Abdominal radiology (New York) (Abdom Radiol (NY)) Vol. 42 Issue 1 Pg. 115-123 (01 2017) ISSN: 2366-0058 [Electronic] United States
• PMID: 27567607 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Biomarkers, Tumor
• Leukocyte L1 Antigen Complex

Topics

• Adolescent
• Adult
• Aged
• Biomarkers, Tumor (analysis)
• Biopsy
• Crohn Disease (diagnostic imaging, pathology)
• Diffusion Magnetic Resonance Imaging (methods)
• Feces (chemistry)
• Female
• Humans
• Leukocyte L1 Antigen Complex (analysis)
• Magnetic Resonance Imaging
• Male
• Middle Aged
• Sensitivity and Specificity