Posterior fossa abnormalities in high-risk term infants: Comparison of ultrasound and MRI

Abstract

Objectives We aimed to assess the characteristics of posterior fossa (PF) abnormalities in a cohort of high-risk term neonates, as well as the diagnostic performance of cranial ultrasound (CUS) with additional mastoid fontanelle (MF) views for the detection of these abnormalities, with magnetic resonance imaging (MRI) being the reference standard. Methods In this retrospective study, 113 term neonates with CUS and subsequent MRI were included. Sensitivity, specificity, and predictive values of routine CUS and CUS with MF views were calculated. Results Posterior fossa abnormalities were diagnosed on CUS in 46 of 113 infants. MRI confirmed these findings in 43 and showed additional abnormalities in 32 infants. The sensitivity and specificity of anterior fontanelle views for major PF abnormalities as seen on MRI were 16 % and 99 %. Adding MF views increased the sensitivity of US to 82 %. The sensitivity and specificity of MF views for the detection of any (major or minor) PF abnormality were 57 % and 95 %. Especially acute hypoxic-ischemic injury and small subdural and punctate cerebellar haemorrhage remained undetected by CUS. Conclusions PF abnormalities are frequent in high-risk term infants. MF-CUS enables early diagnosis of major PF abnormalities. We therefore advocate to perform MF-CUS in high-risk term neonates. Key Points • Posterior fossa abnormalities are a frequent finding in highrisk term infants.• Adding mastoid fontanelle views improves ultrasound detection of clinically relevant abnormalities.• Hypoxic-ischemic injury and small posterior fossa haemorrhages are better detected with MRI.• Cranial ultrasound examination should include mastoid fontanelle views in high-risk term neonates.

Head Ultrasound in Neonatal Hypoxic-Ischemic Injury and Its Mimickers for Clinicians: A Review of the Patterns of Injury and the Evolution of Findings Over Time

“…In addition, a wide array of developmental disorders such as Chiari and Dandy Walker malformations and corpus callosum agenesis/dysgenesis, as well as vascular anomalies such as vein of Galen aneurysmal malformation, ventriculomegaly, and migrational abnormalities can also be revealed [8]. Detection of posterior fossa pathologies has been greatly enhanced by the addition of posterior and mastoid fontanel views to the standard anterior fontanel approach [9,10]. Cranial US has many roles in evaluating patients when there is a concern for neonatal HII.…”

Extended Cranial Ultrasound Views in Infants with Acute Brain Stem/Infratentorial Lesions: Diagnosis of a Progressive Midline Glioma in a 6-Week-Old Infant

“…The study showed that the additional examination via the MF increased the sensitivity, as well as the specificity, of the cranial ultrasound. 12 Recently, the same working group published a detailed description of the examination of the fossa posterior. 13 Specifically, in preterm infants, CUS has reached a new significance due to the possibility of detecting the smallest bleedings in the cerebellum.…”

Cranial Ultrasound Is an Important Tool in the Recognition of Life-Threatening Infratentorial Hemorrhage in Newborns

“…19 However, the detection of posterior fossa hemorrhages by CUS may be difficult. 20 This is mainly due to the large distance between the AF and the posterior fossa. Despite this limitation, it is important to be aware that there are very specific clues on the AF views that can raise the suspicion of a large infratentorial hemorrhage.…”