title: Three-dimensional sonographic description of abnormal metopic suture in second- and third-trimester fetuses.
abstract: OBJECTIVE
  To describe patterns of abnormal development of the metopic suture in association with fetal malformations during the second and third trimesters of pregnancy.
  
  
  METHODS
  This was a cross-sectional study of the frontal bones and metopic suture in 11 fetuses at 17-32 weeks of gestation. Cases were selected because there were obvious abnormalities in the metopic sutures. In each case, a malformation was detected by two-dimensional (2D) ultrasound and the abnormality of the metopic suture was detected and evaluated on three-dimensional (3D) ultrasound, using transparent maximum mode.
  
  
  RESULTS
  There were essentially four patterns of abnormality in the metopic suture: firstly, delayed development with a V- or Y-shaped open suture, which is found in normal fetuses at 12-16 weeks; secondly, a U-shaped open suture, presumably due to upward growth of the frontal bones with delayed closure; thirdly, premature closure of the suture, which is normally observed after 32 weeks; fourthly, the presence of additional bone between the frontal bones. Premature closure of the suture or additional bone between the frontal bones was observed in fetuses with holoprosencephaly and abnormalities of the corpus callosum, whereas the V-, Y- and U-shaped metopic sutures were observed in fetuses with facial defects involving the orbits, nasal bones, lip, palate and mandible, in the absence of holoprosencephaly and abnormal corpus callosum.
  
  
  CONCLUSIONS
  This preliminary study describes the pattern of possible abnormalities of the metopic suture and should stimulate further investigation to establish the prevalence and evolution of abnormal sutures as well as the incidence and pattern of other associated defects.
authors.affiliation: Center for Prenatal Diagnosis and Human Genetics, Berlin, Germany.
authors.forename: R
authors.initials: R
authors.lastname: Chaoui
authors.forename: J M
authors.initials: JM
authors.lastname: Levaillant
authors.forename: B
authors.initials: B
authors.lastname: Benoit
authors.forename: C
authors.initials: C
authors.lastname: Faro
authors.forename: P
authors.initials: P
authors.lastname: Wegrzyn
authors.forename: K H
authors.initials: KH
authors.lastname: Nicolaides
mesh_terms: D000015:Abnormalities, Multiple / Q000000981:diagnostic imaging; D003393:Cranial Sutures / Q000002:abnormalities / Q000000981:diagnostic imaging* / Q000196:embryology*; D003430:Cross-Sectional Studies; D005145:Face / Q000002:abnormalities / Q000000981:diagnostic imaging; D005260:Female; D047109:Fetal Development; D005315:Fetal Diseases / Q000000981:diagnostic imaging*; D005624:Frontal Bone / Q000002:abnormalities / Q000000981:diagnostic imaging / Q000196:embryology; D006801:Humans; D021621:Imaging, Three-Dimensional; D011247:Pregnancy; D016216:Ultrasonography, Prenatal / Q000379:methods