5 Commandments in reporting of Crohn's disease on MR Enterography

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 5 Commandments in reporting of Crohn's disease on MR Enterography



MR Enterography in Crohn's Disease

Introduction

Magnetic Resonance Enterography (MRE) is a non-invasive imaging modality crucial for assessing small bowel involvement in Crohn's disease. It provides detailed evaluation of bowel wall inflammation, strictures, fistulas, abscesses, and extra-intestinal manifestations without ionizing radiation.

Oral Contrast Preparation

Agent: 3.3% Mannitol solution

Volume: 1.2–1.5 liters

Administration: Divided into 3 portions over 45–60 minutes; final dose immediately before scanning

Purpose: Optimal small bowel distension for mucosal and transmural evaluation

Alternatives: Polyethylene glycol (PEG), Low-density barium (VoLumen)

Premedication

Anti-peristaltic Agent: Buscopan (Hyoscine Butylbromide) 20 mg IV or Glucagon 0.5–1 mg IV/IM

Purpose: Minimize bowel motion artifacts during dynamic contrast and high-resolution sequences

MRI Acquisition Protocol

1. Localizer (Scout): Multiplanar T2-weighted for anatomical orientation

2. T2-Weighted SSFSE (Coronal and Axial): No fat saturation, Assess wall thickening and luminal content

3. Post-Contrast T1-Weighted Fat-Saturated GRE (Axial and Coronal): Gadolinium 0.1 mmol/kg, Dynamic Phases (30s, 60s, 3–5 min)

4. Diffusion-Weighted Imaging (DWI): b-values: 0, 400, 800 s/mm², Detect restricted diffusion

5. Optional Delayed Post-Contrast Imaging: 5–7 min for late enhancement

6. Optional:  T2-Weighted Fat-Saturated (Coronal and Axial): Detect mural edema, inflammation, collections

 

Rationale for Early Post-Contrast Imaging

 

·         Most critical for assessing disease activity.

·         Prevents oral contrast progressing into colon, preserving small bowel distension.

·         Maximizes effect of antiperistaltic agents (Buscopan/Glucagon).

Structured Reporting Template

 

Bowel Involvement: Location, Length, Wall Thickness, Enhancement, Diffusion, Narrowing

Small Bowel Obstruction: Level, Transition Zone, Dilation

Mesenteric Changes & Lymphadenopathy: Comb Sign, Creeping Fat, Nodes

Skip Lesions / Abscess / Fistula: Presence, Size, Type

Additional Findings: Perianal disease, Sacroiliitis

Interpretation Summary

 

Active Crohn’s disease involving [location]. Complications: [e.g., stricture, fistula, abscess]. Recommend follow-up in 6–12 months.

Plain Language Summary

 

Your scan shows areas of inflammation in the small bowel consistent with Crohn’s disease. Some sections are narrowed, and there may be a small pocket of infection or an abnormal connection between loops of the bowel. These findings help guide treatment and assess your response to therapy.

 

References

 

 1. Maccioni F. et al. Radiology. 2013.

2. AJR 2012. MR Enterography Part II: Imaging-Pathologic Correlation.

3. PMID: 38031220. Mannitol concentration in oral contrast.


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