Can an abdominal ultrasound (US) detect a gastric ulcer?

Abdominal Ultrasound for Detecting Gastric Ulcers

Abdominal ultrasound has limited sensitivity for detecting gastric ulcers and should not be used as the primary diagnostic tool for this purpose. While ultrasound can sometimes identify gastric wall abnormalities, its overall sensitivity for detecting gastric ulcers is poor (approximately 40% in pediatric patients), making it an unreliable first-line imaging modality for this specific condition 1.

Limitations of Ultrasound for Gastric Ulcer Detection

• Low sensitivity: Direct ultrasound imaging findings alone have low sensitivity for diagnosing gastric ulcers (40%) 1
• Operator dependence: Abdominal ultrasound accuracy varies widely and is highly operator-dependent 2
• Technical challenges:
  • Presence of intestinal gas often obscures visualization 2, 3
  • Anatomical location of the stomach makes complete evaluation difficult
  • Standard abdominal ultrasound without special preparation may miss gastric pathology

When Ultrasound Might Detect Gastric Ulcers

Ultrasound may occasionally detect gastric ulcers under specific circumstances:

1. Large ulcers: Detection rates improve significantly with increasing ulcer size (100% for ulcers >15mm vs. 32% for ulcers ≤5mm) 4
2. Special techniques: Using oral contrast agents can improve detection:
   • Transabdominal ultrasound with cellulose-based oral contrast agent (TUS-OCCA) can detect up to 76% of gastric ulcers 4
   • Water ingestion before examination may improve visualization 5
3. Complicated ulcers: Penetrating or perforated ulcers may be more readily detected due to associated findings:
   • Wall edema
   • Free fluid
   • Inflammatory changes in surrounding tissues 6

Recommended Diagnostic Approach for Suspected Gastric Ulcers

For patients with suspected gastric ulcers, the following diagnostic approach is recommended:

1. Endoscopy: First-line diagnostic tool for direct visualization and biopsy
2. CT scan: If endoscopy is not immediately available, CT provides better overall abdominal evaluation
3. Ultrasound: Consider only in specific situations:
   • When other imaging modalities are unavailable
   • For monitoring known ulcers during treatment 4
   • In pediatric patients where radiation exposure is a concern 2
   • When specialized techniques with oral contrast are available 4

Conclusion

While abdominal ultrasound may be useful for evaluating many abdominal conditions, it should not be relied upon to rule out gastric ulcers. The American College of Radiology guidelines do not recommend ultrasound as a primary diagnostic tool for suspected gastric pathology 2. Endoscopy remains the gold standard for diagnosing gastric ulcers, providing direct visualization, the ability to obtain biopsies, and assessment of healing during follow-up.