Intussusception (Radiology)

Intussusception의 Key imaging features는 multiple layered target like lesion.

Imaging features

USG

• Oval hypoechoic mass
  • Pseudokidney or doughnut sign
  • Hypoechoic rim with central echogenicity
  • Multiple layers and concentric rings
• Small amount of peritoneal fluid or Large amount of peritoneal fluid(suggests perforation, especially echogenic ascites)
• Diameter
  • Mean diameter: 2.63 cm(range, 1.3–4.0 cm) for ileocolic intussusception(1.42 cm(range, 0.8–3.0 cm) for small-bowel intussusception)
• Etc
  • Spontaneous reduction of intussusception is a well-known phenomenon that has been documented sonographically
  • Transient small bowel intussusception is a common occurrence, especially in patients with hyperperistalsis
    • not associated with substantial edema in the intussuscepted loops->thinner peripheral rim

Differential diagnosis

• Transient small bowel intussuseption: target like lesion으로 보여 감별이 필요함.
  • 비교적 작은 직경과 길이, wall thickness에 비해 inner fat core의 크기가 작음
• Psoas muscle(pitfall)

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