Ultrasound Reference Range for Diameters of Posterior Atrium of Lateral Ventricles for Normal Nigerian Foetuses, at the University College Hospital (UCH) Ibadan, Nigeria: A Cross – Sectional Study

Aims: The diameter of the posterior atrium of the lateral cerebral ventricles (PALV) does not vary substantially in size during foetal development and has thus become a stable marker for the identification of foetal ventriculomegaly in developed countries. Currently, the accepted upper limit of PADLV is 10 mm. Ventricular atrial diameters greater than 10mm require more radiological evaluation to rule out ventriculomegaly.
The aim of this study was to establish the normal range of values for the posterior atrium [PA] of foetal lateral ventricles in our environment and to determine a cut-off value for prenatal diagnosis of ventriculomegaly.
Methods: The mean of two measurements was obtained from the transverse diameter of the atrium of the lateral ventricles of foetuses that met the inclusion criteria, as part of the routine obstetric ultrasound scan at the antenatal clinic or ultrasound suite of radiology department of the University College Hospital (UCH), Ibadan. The SPSS version 15 was used to analyse the data obtained.
Results: The mean posterior atrial diameter [PAD] of the lateral ventricl was 6.5mm with standard deviation (SD) 1.3mm and mean ±2SD 3.9–9.1mm. Male foetuses had larger atrial diameters than female. Student’s t-test and Pearson’s correlation coefficient were used to explore association.
Conclusion: With the existing resources in our environment, prenatal screening for ventriculomegaly during routine obstetric scan is achievable. Measurement of 10mm is a reasonable upper limit of normal in our environment. Foetuses with larger values need further evaluation to rule out hydrocephalus.