Normal Ultrasonographic Dimensions of the Liver in Neonates in South-West Nigeria

Ultrasound (US) is first choice of imaging in children suspected to have liver pathology because it is cheap, quick to perform with no radiation risks. Liver size may be increased or decreased in many pathological conditions and ultrasound is ideal since clinical evaluation by palpation and/or percussion can be unreliable or inaccurate.

To our knowledge, no previous study has been done in an exclusively large neonatal population in Sub-Saharan Africa to establish reference values for the liver size. This study aims to determine by USS, the normal range of longitudinal dimensions for the liver in healthy neonates.

A prospective cross-sectional study of 508 apparently healthy neonates. Routine clinical examination and liver ultrasound scans were performed before discharge or at the immunization clinic. Liver size was taken as the longitudinal dimension in the mid-clavicular line. Normograms with point-wise 95% reference ranges were constructed using a normal approximation.

Mean age was 9.67 ± 7.68 days and 51.4% were males. Ultrasound span of the liver ranged from 3.28-8.02 cm with a mean of 5.72 ± 0.88 cm. There was no evidence for sex difference in the liver size, p= 0.338. The liver size correlated most strongly with neonatal weight (r=0.55) and age (r=0.53) which were used in plotting the 95% reference ranges for the neonatal liver normogram.

This study of a large neonatal population has provided the normal range of US liver dimensions for neonates in the study area, using the age and weight in plotting the 95% reference ranges for the liver normogram.