[CG] Fetal cerebral ventricular measurement


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Assessment of the integrity of the fetal ventricular system is made using measurements of the ventricular atrium (posterior horn of the lateral ventricle). An atrial width of less than 10mm should be considered normal. A measurement between 10-15mm constitutes mild ventriculomegaly and measurements greater than 15mm constitute severe ventriculomegaly (1).

Ventricular atrial measurements greater than 10mm should be reported and the patient referred for further assessment as for any other fetal anomaly (2).

Measurement of atrial size

  1. A strict axial transverse view should be obtained of the fetal head at the level of the thalami as for HC assessment.

  2. Anteriorly the cavum septum pellucidum should be demonstrated and posteriorly the fluid filled triangular V shape of the ambient cistern

  3. Measurement should be performed at the level of the glomus of the choroid plexus (3)

  4. Callipers should be placed perpendicular to the long axis of the ventricle.

  5. Measurements should be ‘on to on’  i.e. junction of ventricular lumen and ventricular wall.

  6. The image should be magnified so that the entire axial trans-ventricular plane occupies the screen with clear visualisation of the proximal and distal caval margins.
  1. Vergani P, Locatelli A, Stroblet N et al. Clinical Outcome of mild fetal ventriculomegaly. Am J Obstet Gynaecol 1998;178:218-222

  2. UK NSC NHS FASP Programme Statement: Normal variant screening policy/statement.

  3. Cardoza JD, Goldstein RB, Filly RA. Exclusion of fetal ventriculomegaly with a single measurement: the width of the lateral ventricular atrium. Radiology 1988;169:711- 714

  4. Guibaud L. Fetal cerebral ventricular measurement and ventriculomegaly: time for procedure standardisation. Ultrasound Obstet Gynecol 2009;34:127-130

Last reviewed: 17 December 2021

Next review: 23 December 2026

Author(s): Donna Maria Bean

Version: 3

Approved By: Obstetrics Clinical Governance Group

Document Id: 491