title: Transabdominal sonography of the cavum septum pellucidum in normal fetuses in the second and third trimesters of pregnancy.
abstract: OBJECTIVE
  To assess the visualization rate and size of the cavum septum pellucidum (CSP) by transabdominal sonography in normal fetuses throughout pregnancy.
  
  
  METHODS
  The CSP was prospectively researched and measured using an axial transventricular plane in 286 consecutive uncomplicated singleton pregnancies between 15 and 41 weeks of gestation.
  
  
  RESULTS
  The CSP was seen in 40% of cases at 15 weeks, 82% at 16-17 weeks, 100% at 18-37 weeks and 79% at 38-41 weeks. Compared to biparietal diameter (BPD), the visualization rate was 33% between 31 and 32 mm, 45% between 33 and 34 mm, 84% between 35 and 43 mm, 100% between 44 and 88 mm and 86% between 89 and 99 mm. Mean CSP width was 5.3 +/- 1.7 mm (range 2-9 mm). The CSP width increased with gestational age and BPD but with a slight decrease around term.
  
  
  CONCLUSIONS
  In normal fetuses the CSP should always be visualized between 18 and 37 weeks, or with a BPD of 44-88 mm. Failure to observe the CSP in this interval, or possibly the presence of a large CSP, may indicate abnormal cerebral development and warrant further investigation. Conversely, absence of the CSP prior to 18 weeks, or later than 37 weeks, is a normal finding.
authors.affiliation: Department of Obstetrics and Gynecology, University of Bologna, Italy.
authors.forename: P
authors.initials: P
authors.lastname: Falco
authors.forename: S
authors.initials: S
authors.lastname: Gabrielli
authors.forename: A
authors.initials: A
authors.lastname: Visentin
authors.forename: A
authors.initials: A
authors.lastname: Perolo
authors.forename: G
authors.initials: G
authors.lastname: Pilu
authors.forename: L
authors.initials: L
authors.lastname: Bovicelli
mesh_terms: D005260:Female; D006801:Humans; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D011263:Pregnancy Trimester, Third; D011446:Prospective Studies; D012016:Reference Values; D012688:Septum Pellucidum / Q000000981:diagnostic imaging*; D016216:Ultrasonography, Prenatal