An Italian study published online June 3 in Child’s Nervous System shows that cranial ultrasound is a highly specific and sensitive first-step choice for imaging infants who show signs of craniosynostosis. That’s the birth defect in which the plates of the skull fuse too early, causing abnormal head shape and potentially putting injurious pressure on the brain.

Laura Pogliani of the University of Milan and colleagues first examined 196 babies (mean age four months) suspected of having the condition with cranial ultrasound, then referred those with positive results to neuroradiologists for skull CT.

The patients with negative results on ultrasound received routine follow-up to watch for changes in head shape.

Of the 196 (122 boys, 74 girls), only two had inconclusive studies, and they were both past infancy (more than 1 year old).

Meanwhile, cranial ultrasound led to synostosis diagnoses in 30 infants. With the exception of two cases revealed as false positives in the starting phase of the study, all 30 were verified by skull CT.

As for specificity, 12 patients with very prominent head deformity and negative cranial ultrasound underwent CT, and the latter exam confirmed the ultrasound results in all of them.

In all children with doubtful synostosis (n = 148) and therefore no CT check, clinicians observed normal head development and ruled out the condition on that basis.

Pogliani et al. write that, in referral centers, expert hands can use cranial ultrasound “as a reliable first-step screening for infants younger than 1 year [who are] suspected to have a craniosynostosis, thus avoiding unnecessary exposure to ionizing radiation.”

The “golden age” to obtain the best cranial ultrasound results is under 6 months, they point out, adding a recommendation for case centralization because accuracy “is operator-dependent and there is a learning curve.”