Aim: To establish normal ranges for the lateral, third, and fourth ventricular dimensions and the ventriculo-hemispheric ratio (VHR) in neonates using cranial ultrasonography.
Method: Intra-cranial ventricles were assessed ultrasonographically using anterior fontanelle as acoustic window. Data were analyzed to determine correlation, coefficient of determination (R2), regression equations and plotted against gestational age (GA).
Results: Of total 1483 neonates (25-42 w GA), 372(25%) had GA < 34 weeks. GA strongly correlated with anterior horn width (AHW; 0.92), thalamo-occipital distance (TOD; 0.94), and third (0.78) and fourth (0.89) ventricular widths. The R2 values were 0.85, 0.88, 0.66 and 0.80, respectively. VHR had weak correlation (0.12, R(2)= 0.005) with GA and stayed constant (0.27-0.28) across GA. Nomograms of AHW, TOD, and third and fourth ventricular widths were constructed with respect to GA.
Conclusion: Intra-cranial ventricles increase in size with GA but this increase is limited to only a few mm and is proportional to increment in brain tissue. Nomograms and regression equations of AHW, TOD and widths of third and fourth ventricles can assist in objectively assessing ventricular sizes. The almost uniform VHR can be used to screen ventricle size while suspecting hydrocephalus.