Pediatric ultrasound

Pediatric FAST and E-FAST

• Pediatric FAST exam less sensitive (but similar specificity) than in adults because more pediatric abdominal injuries do not have associated free fluid.
• Sensitivity 66%. Specificity 95%.
• Some advocate combining FAST with LFTs (improved sensitivity to 88%) or FAST and observed for 6 hours.
• Future of FAST may include ultrasound with intravenous contrast.
• Procedurally is similar to adult FAST and E-FAST

Pediatric Skull Ultrasound

• Absence of skull fracture does not rule out intracranial injury but can be used to risk stratify.
• Sensitivity of 94%-100%. Specificity of 95%-96%. (albeit less literature on this topic)
• Skull x-rays have sensitivity 38% and specificity of 95%

Procedure

• Place probe on area with maximal tenderness, hematoma, or other sign of possible fracture. Scan in 2 planes. Look for disruptions in cortex. Sutures can be identified by following cortical break to a fontanelle and/or comparing contralateral side. Fractures will have ragged, sharp margins. Sutures will have smooth appearance.

Intravascular Volume Assessment

• In pediatrics, comparison of IVC to aorta ratio may be more reliable than respiratory variation of IVC alone

Procedure

• IVC-to-aorta ratio less than 0.8 has sensitivity of 86-93% and specificity of 54-59% for severe dehydration (compared to WHO dehydration scale which has sensitivity of 73%, specificity of 43%).
• Subcostal view of IVC. Measure IVC at point of entry of hepatic vein or 2cm distal to cavoatrial junction. Measurements are taken at maximal diameters of structures (freeze and scroll back during cardiac and respiratory cycles).

Intussusception

• Start with high frequency probe in right lower quadrant and scan all 4 quadrants in a lawnmower fashion.
• While scanning each quadrant, use graded compression in every 1-2 cm looking for the following signs.
  • Pseudokidney or sandwich sign seen on long axis
  • Target sign on short axis

See Also

• Ultrasound (Main)