title: Posterior fossa abnormalities in high-risk term infants: comparison of ultrasound and MRI.
abstract: OBJECTIVE
  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.
  
  
  CONCLUSIONS
  • Posterior fossa abnormalities are a frequent finding in high-risk 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.
authors.affiliation: Department of Neonatology, Leiden University Medical Centre, Leiden, The Netherlands, s.j.steggerda@lumc.nl.
authors.forename: S J
authors.initials: SJ
authors.lastname: Steggerda
authors.forename: F T
authors.initials: FT
authors.lastname: de Bruïne
authors.forename: V E H J
authors.initials: VE
authors.lastname: Smits-Wintjens
authors.forename: P
authors.initials: P
authors.lastname: Verbon
authors.forename: F J
authors.initials: FJ
authors.lastname: Walther
authors.forename: G
authors.initials: G
authors.lastname: van Wezel-Meijler
mesh_terms: D002526:Cerebellar Diseases / Q000175:diagnosis*; D002531:Cerebellum / Q000002:abnormalities* / Q000000981:diagnostic imaging / Q000473:pathology; D015331:Cohort Studies; D055762:Cranial Fontanelles / Q000000981:diagnostic imaging / Q000473:pathology; D004453:Echoencephalography; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D008279:Magnetic Resonance Imaging; D008297:Male; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity