Which imaging modality is used to diagnose intussusception?

• A. CT scan
• B. Ultrasound
• C. X-ray
• D. Magnetic resonance imaging

Answer: (A)

Ultrasound is the imaging study of choice for diagnosing intussusception. In children, it can directly visualize the telescoped bowel and shows classic signs such as the target (donut) sign in cross-section and the pseudokidney sign in longitudinal view. It’s fast, can be done at the bedside, and crucially, it avoids radiation exposure. In addition, ultrasound can guide or accompany nonoperative reduction with hydrostatic or pneumatic enemas when appropriate.

CT scanning, while highly sensitive, involves ionizing radiation and is generally reserved for adults or when ultrasound results are inconclusive or there are concerns for complications or atypical presentations. X-ray may reveal indirect signs like bowel obstruction but does not confirm intussusception. MRI is not typically used due to longer exam times and the need for patient cooperation or sedation.