title: Brainstem-vermis and brainstem-tentorium angles allow accurate categorization of fetal upward rotation of cerebellar vermis.
abstract: OBJECTIVE
  To evaluate the role of the brainstem-vermis (BV) and brainstem-tentorium (BT) angles in the differential diagnosis of upward rotation of the fetal cerebellar vermis.
  
  
  METHODS
  The BV and BT angles were measured retrospectively on median sonographic views of the brain in 31 fetuses at 19-28 weeks' gestation with upward rotation of the cerebellar vermis due to Blake's pouch cyst (n = 12), Dandy-Walker malformation (n = 12) and cerebellar vermian hypoplasia (n = 7). Eighty normal fetuses at 20-24 weeks were included as controls.
  
  
  RESULTS
  In the control group, BV and BT angles were 9.1 ± 3.5° (range, 4-17°) and 29.3 ± 5.8° (range, 21-44°), respectively. The BV angle was significantly increased in each of the three subgroups of anomalies: Blake's pouch cyst (23 ± 2.8°; range, 19-26°), vermian hypoplasia (34.9 ± 5.4°; range, 24-40°) and Dandy-Walker malformation (63.5 ± 17.6°; range, 45-112°), the angle increasing with increasing severity of the condition. The BT angle had a similar pattern but there was overlap among the different groups.
  
  
  CONCLUSIONS
  The BV angle and, to a lesser degree, the BT angle are simple and reproducible measurements that provide valuable additional information for the categorization of upward rotation of the fetal cerebellar vermis. From mid gestation, a BV angle > 45° is strongly suggestive of a Dandy-Walker malformation, while a measurement < 30° favors the diagnosis of a Blake's pouch cyst.
authors.affiliation: Fetal Medicine Unit, Di Venere and Sarcone Hospitals, ASL Bari, Bari, Italy.
authors.forename: P
authors.initials: P
authors.lastname: Volpe
authors.forename: E
authors.initials: E
authors.lastname: Contro
authors.forename: F
authors.initials: F
authors.lastname: De Musso
authors.forename: T
authors.initials: T
authors.lastname: Ghi
authors.forename: A
authors.initials: A
authors.lastname: Farina
authors.forename: A
authors.initials: A
authors.lastname: Tempesta
authors.forename: G
authors.initials: G
authors.lastname: Volpe
authors.forename: N
authors.initials: N
authors.lastname: Rizzo
authors.forename: G
authors.initials: G
authors.lastname: Pilu
mesh_terms: D016080:Arachnoid Cysts / Q000000981:diagnostic imaging* / Q000196:embryology; D001933:Brain Stem / Q000002:abnormalities / Q000000981:diagnostic imaging* / Q000196:embryology; D002531:Cerebellum / Q000002:abnormalities / Q000000981:diagnostic imaging* / Q000196:embryology; D003388:Cranial Fossa, Posterior / Q000002:abnormalities / Q000000981:diagnostic imaging* / Q000196:embryology; D003616:Dandy-Walker Syndrome / Q000000981:diagnostic imaging* / Q000196:embryology; D003937:Diagnosis, Differential; D005260:Female; D005865:Gestational Age; D006801:Humans; D011247:Pregnancy; D015203:Reproducibility of Results; D016216:Ultrasonography, Prenatal / Q000379:methods*