Cranial Ultrasonographic Findings in Healthy Full-term Neonates: a Retrospective Review

Background: Ultrasonography is a non-invasive diagnostic technique, and it has been used to detect intracranial lesions in neonates for a long time. Correspondingly, screening tests using cranial ultrasonography have been applied for early detection of intracranial lesions in full-term neonates during the past decade.

Methods: We retrospectively reviewed the findings of cranial ultrasonographic screening tests in healthy full-term neonates between September 2004 and August 2009. The ultrasonographic findings were divided into the following categories: (a) nonsignificant (NS) group, including normal and normal variations, (b) minor anomaly group, including tiny cystic lesions, mild hemorrhage, or mild ventricular anomaly, and (c) major anomaly group, including significant anomaly of any intracranial pathology. The participants with major anomalies were further reviewed, and the following medical records of all enrolled patients were reviewed until they were 24 months of age.

Results: There were a total of 3186 neonates who received cranial ultrasonographic screening examination during the 5-year period, and most of them (2982 cases, 93.6%) were assigned to the NS group. The most common normal variation was the presence of cavum septum pellucidum (1979 cases, 62.1%). Minor anomalies were found in 202 (6.3%) neonates, including 119 (3.7%) neonates with tiny cysts, and 59 (1.9%) neonates with mild intraventricular hemorrhage. Major anomalies were found in two (0.06%) neonates, including obstructive hydrocephalus and agenesis of the corpus callosum. Two other infants (0.06%) initially presented with minor anomaly or normal variation, but they were diagnosed as Moyamoya disease and neonatal seizure some months later.

Conclusion: The incidence of minor and major anomalies detected by cranial ultrasonographic screening examinations in healthy full-term neonates is 6.3% and 0.06%, respectively. Thus, cranial ultrasonographic screening testing may play a role in the early diagnosis of intracranial anomalies of otherwise healthy neonates. However, this examination cannot exclude or detect all cranial abnormalities, including many potential neurologic diseases of neonates, so continuing clinical diligence is still important for all infants.