Lack of normal duodenal canalization leading to partial (web/stenosis) or complete obstruction (atresia)

Double bubble : Fluid-filled stomach and duodenum

Persistent fluid in duodenum is always abnormal

Hyperperistalsis of stomach on real-time imaging

Fetal regurgitation may intermittently decompress stomach

Polyhydramnios; may be severe in 3rd trimester

Distal atresias (jejunal, ileal, colonic, anal) will all have multiple dilated loops of bowel

Abdominal cysts

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  None will communicate with stomach

  
  
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  Polyhydramnios not feature

Duodenum most common site of intestinal obstruction

30% of duodenal atresia (DA) cases have trisomy 21

5-15% of trisomy 21 cases have DA

Overall mortality is 15-40%

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  Dependent on associated abnormalities

Isolated defect in liveborn; 95% survival with prompt surgical treatment

50-70% of DA cases have other anomalies

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  Cardiac and other GI malformations are most common

Continuity with stomach confirms diagnosis

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  May be better demonstrated in coronal plane if stomach is severely distended

  
  
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  Peristalsis with thick gastric folds easily identified on real-time scanning

Look for other findings of T21

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  Cardiac malformations: Atrioventricular septal defect, ventricular septal defect, tetralogy of Fallot

  
  
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  Markers: Nuchal thickening, short femur/humerus, absent/hypoplastic nasal bone, mild ventriculomegaly, echogenic bowel, echogenic cardiac focus, pelviectasis