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2002-02-11-14 Ultrasound examination in the first trimester © Novakov www.thefetus.net/


Ultrasound examination in the first trimester

Aleksandra Mikic Novakov, MD

Novi Sad, Yugoslavia

Normal fetal morphology

  • complete ossification of the skull
  • choroid plexuses fill the skull
  • "butterfly shape" of the choroid plexuses
  • uninterrupted midline echo

Fetal profile

  • visible nasal bone

  • measurement of the nuchal lucency

Transverse section of the abdomen  

  • abdominal wall closed 
  • normal size of the stomach

Longitudinal section of the fetus

  • diaphragm
  • stomach seen below the diaphragm

Transverse section of the abdomen at the level of the cord insertion

  • anterior abdominal wall closed
  • normal insertion of the umbilical cord

Fetal bladder

  • bladder seen, normal size

 

Fetal legs

  • check for existence of both legs
  • all long bones and both feet seen

 

Fetal hands

  • both hands seen
  • all long bones and fingers seen

 

Measurement of nuchal translucency (Snijders RJM et al)

 

  • gestational age 11 - 14 weeks (CRL 45-84 mm) (Snijders RJM, Nicolaides KHN) 
  • maximal enlargement of the image (fetus occupies 75% of the whole image) 
  • longitudinal section of the fetus (profile clearly seen) 
  • fetus away from the amnion (three parallel lines seen) 
  • the biggest thickness behind the neck is measured
  • calipers put on the tissue following the rule "on/on"

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