RadteraCT Enterography
CT+ ContrastAbdomen & Pelvis
Indications
- Crohn disease evaluation (activity, complications: stricture, fistula, abscess)
- Obscure GI bleeding, small bowel tumor evaluation
- Assessment of small bowel inflammation
Patient prep
- NPO 4-6 h before exam
- Oral neutral (low-density) contrast: ~1350 mL of dilute (e.g., 0.1% barium sulfate like VoLumen, or PEG/mannitol solution) over ~45-60 min to distend small bowel
- Optional IV antiperistaltic (glucagon) to reduce motion if protocol uses it
- 18-20G IV; check renal function
Contrast
AgentOral neutral contrast (low-HU) + IV iodinated
Routeoral + IV
Dose~1350 mL oral neutral contrast; IV 100-150 mL at 4-5 mL/s (weight-based)
TimingIV enteric/late-arterial-to-enteric phase ~45-50 s for bowel wall enhancement; some add portal venous ~70 s; single enteric phase common
Technique
- Supine, arms up; coverage diaphragm through pelvis
- 120 kV (100 kV thin); dose modulation
- Enteric phase (~45-50 s) optimizes mural hyperenhancement; thin recon 1-1.25 mm with 2.5-3 mm review
- Coronal reformats essential for small bowel survey
- Neutral oral contrast keeps lumen low density so mucosal hyperenhancement is visible
Series / Sequences
| # | Series / Sequence | Plane | Thickness | Notes |
|---|---|---|---|---|
| 1 | Axial enteric | axial | 1.25-3 mm | Mural enhancement, wall thickening |
| 2 | Coronal reformat | coronal | 2-3 mm | Loop-by-loop small bowel survey |
| 3 | Thin axial | axial | 1-1.25 mm | Reformats |
Key points
- Adequate small bowel distention with neutral oral contrast is critical; under-distention mimics or hides disease
- Enteric phase (~45-50 s) best shows bowel wall hyperenhancement of active inflammation
- Look for mural hyperenhancement, wall thickening, comb sign, fat stranding, strictures, fistulae, abscess
- MR enterography preferred for young patients needing repeated follow-up (no radiation)
- Neutral (not positive) oral contrast is the key difference from routine abdominal CT
References
• ACR-SAR-SPR Practice Parameter for the Performance of CT Enterography
• Radiopaedia: CT enterography ( link
• RadioGraphics: CT Enterography of Crohn Disease
• Radiopaedia: CT enterography ( link
• RadioGraphics: CT Enterography of Crohn Disease
Source: Researched — verify against your institution
Reference template — verify and adapt to your scanner, vendor and institution before clinical use. Not a substitute for clinical judgment.