CT Enterography (CTE)

CT Enterography (CTE) – Detailed Overview

CT Enterography is a specialized CT scan technique used to evaluate the small intestine with high-resolution imaging. It is particularly useful for detecting inflammatory bowel disease (IBD), tumors, vascular abnormalities, and other small bowel disorders.

1. Indications (Why It’s Done)

CT Enterography is commonly used for:
✅ Inflammatory Bowel Disease (IBD) – Crohn’s disease, ulcerative colitis
✅ Small Bowel Obstruction – Partial or complete blockage
✅ Tumors & Masses – Neuroendocrine tumors, adenocarcinoma, lymphoma
✅ Celiac Disease Complications – Strictures, ulcers
✅ Gastrointestinal Bleeding – Unexplained or occult bleeding
✅ Vascular Abnormalities – Mesenteric ischemia
✅ Fistulas & Abscesses – Common in Crohn’s disease

2. Procedure & Preparation

a) Patient Preparation

• Fasting: 4–6 hours before the scan

• Oral Contrast: Patients drink a large volume (1–1.5 liters) of neutral oral contrast (e.g., polyethylene glycol or low-density barium) over 45–60 minutes to distend the bowel

• IV Contrast: A rapid bolus of IV contrast is used to enhance blood vessels and differentiate bowel wall pathology

b) Scan Phases

• Pre-contrast Phase (if needed) – For baseline images

• Arterial Phase (~35 sec post-contrast) – Assesses vascular supply

• Venous Phase (~50-60 sec post-contrast) – Evaluates bowel wall enhancement

• Delayed Phase (~5-7 min if needed) – For further evaluation of abnormalities

3. Key Imaging Findings

• Inflammation (Crohn’s Disease):
  🔹 Bowel wall thickening (>3 mm)
  🔹 Mucosal hyperenhancement
  🔹 Fat stranding & engorged vasa recta (“comb sign”)
  🔹 Strictures, fistulas, or abscesses

• Tumors & Masses:
  🔹 Enhancing soft tissue masses
  🔹 Lymphadenopathy
  🔹 Obstructive features

• Bowel Obstruction:
  🔹 Dilated loops of small bowel (>3 cm)
  🔹 Transition point identification

• Mesenteric Ischemia:
  🔹 Non-enhancing bowel wall (suggesting infarction)
  🔹 Pneumatosis intestinalis (gas within the bowel wall)

4. Advantages of CT Enterography Over Other Imaging

✔ More detailed than standard CT abdomen for small bowel evaluation
✔ Faster & less invasive than capsule endoscopy for Crohn’s disease
✔ Better visualization of deep bowel loops compared to ultrasound
✔ Detects complications (strictures, fistulas, abscesses) accurately

5. Limitations & Considerations

❌ Radiation exposure (MRI Enterography is an alternative for young patients)
❌ Requires good patient compliance with oral contrast ingestion
❌ May be less sensitive for mild or early Crohn’s disease