Pediatric Ultrasonography

Neonatal Cranial US - Brainy Waves

• Indications: Prematurity (< 32 wks), Low Birth Weight (LBW < 1500g), Hypoxic-Ischemic Encephalopathy (HIE), seizures, suspected Intracranial Hemorrhage (ICH), hydrocephalus.
• Windows: Anterior fontanelle (AF) primary; posterior fontanelle (PF) & mastoid fontanelle for posterior fossa evaluation.
• Views: Standard coronal & sagittal sweeps through AF.
• Key Anatomy: Ventricles (size, morphology), choroid plexus, caudothalamic groove (germinal matrix site), corpus callosum, Sylvian fissures, cerebellum.
• Pathologies:
  • Germinal Matrix Hemorrhage-Intraventricular Hemorrhage (GMH-IVH): Papile Grading (I: subependymal; II: IVH, no dilatation; III: IVH + dilatation; IV: parenchymal involvement).
  • Periventricular Leukomalacia (PVL): Ischemic injury; initial echodensities → subsequent cystic changes in periventricular white matter.
  • Hypoxic-Ischemic Encephalopathy (HIE): ↑Brain echogenicity, loss of gray-white differentiation, basal ganglia/thalamic changes.
  • Hydrocephalus: Ventricular dilatation; assess for obstruction.

⭐ Germinal matrix hemorrhage (GMH) is most common in premature infants, especially < 32 weeks gestation and < 1500g birth weight, typically originating in the subependymal region of the caudothalamic groove.

Pediatric GI US - Gut Feelings

• Hypertrophic Pyloric Stenosis (HPS)

  • Pyloric muscle thickness (PMT) > 3-4 mm (key diagnostic)
  • Pyloric channel length (PCL) > 15-17 mm
  • Target sign (transverse), "Antral nipple" / "Cervix sign" (longitudinal)
  • No passage of gastric contents; exaggerated peristalsis

• Intussusception

  • Target/Doughnut sign (transverse), Pseudo-kidney sign (longitudinal)
  • Absent/reduced color Doppler flow suggests ischemia
  • Lead point search (e.g., Meckel's diverticulum, polyp, lymphoma)

  ⭐ Most common site: Ileocolic (approx. 90%)

• Appendicitis

  • Non-compressible, blind-ending tubular structure > 6-7 mm diameter
  • Wall thickness > 2 mm; appendicolith (often with acoustic shadow)
  • Periappendiceal fat inflammation/fluid, hyperemia

• Malrotation with Midgut Volvulus

  • "Whirlpool sign": Superior Mesenteric Vein (SMV) & mesentery wrap around Superior Mesenteric Artery (SMA) clockwise
  • Inverted SMA/SMV relationship (SMV to left of SMA)
  • Dilated proximal bowel loops

Pediatric GU & HB US - Flow & Glow

• Renal US:
  • Hydronephrosis: APD for grading.
    • APD <7mm (mild), 7-15mm (moderate), >15mm (severe).
  • VUR: Check renal size, scarring.
  • PUJ Obstruction: Pelvicalyceal dilatation, normal ureter.
  • MCDK: Non-communicating cysts, no normal parenchyma.
  • Wilms' Tumor: Heterogeneous mass, claw sign.
• Bladder US: Wall <3mm (distended), <5mm (empty); PVR.
• Scrotal US:
  • Testicular Torsion: Absent Doppler flow (📌 Surgical emergency!).
  • Epididymo-orchitis: ↑Doppler flow (hyperemia).
• Ovarian US: Torsion: Enlarged, stromal edema, peripheral follicles, ↓/absent flow.
• Hepatobiliary (HB) US:
  • Biliary Atresia: Triangular cord sign, small/absent GB (post-prandial).
  • Choledochal Cyst: Biliary tree cystic dilatation.
  • Hepatoblastoma: Commonest pediatric liver Ca.

⭐ Triangular cord sign (>4mm thickness) is highly specific for biliary atresia.

Pediatric Hip & Spine US - Joint & Cord Patrol

• Hip US (DDH Screening):
  • Indications: Breech, +ve family Hx, clicky hip (Ortolani/Barlow).
  • Timing: Ideal 4-6 weeks (up to 4-6 months).
  • Graf Classification (α = bony roof, β = cartilage):
    • Type I (Normal): α > 60°, β < 55°.
    • Type IIa (Immature < 3mo): α 50-59°.
    • Abnormal: α < 50° or persistent Type IIa > 3mo.
  • Signs: Shallow acetabulum, femoral head displacement.
• Spine US (Tethered Cord/Dysraphism):
  • Indications: Sacral dimple/pit, hairy patch, hemangioma.
  • Timing: Best < 3 months (up to 6 months) due to posterior element ossification.
  • Normal: Conus medullaris at L1-L2 (not below L3). Filum terminale < 2 mm. Mobile nerve roots.
  • Tethered Cord: Low conus, thick filum (> 2 mm), ↓ cord/root motion.

⭐ Conus medullaris normally terminates at or above the L2-L3 intervertebral disc space in neonates; termination below L3 is abnormal after birth (term infants).

High‑Yield Points - ⚡ Biggest Takeaways

• Intussusception: Look for Target/Doughnut sign (transverse) and Pseudokidney sign (longitudinal).
• HPS: Pyloric muscle >3 mm thick, canal >14 mm long. Key signs: cervix sign, antral nipple sign.
• DDH: Graf classification (alpha, beta angles) is standard. Correlates with Barlow/Ortolani maneuvers.
• Neonatal Cranial USG: Via anterior fontanelle; essential for IVH, PVL, hydrocephalus.
• Pediatric Renal USG: Assesses hydronephrosis (AP diameter), congenital anomalies, indirect VUR signs.
• Acute Appendicitis: Non-compressible appendix >6 mm, target sign, periappendiceal inflammation/fluid.