title: A prospective study on fetal posterior cranial fossa assessment for early detection of open spina bifida at 11-13 weeks.
abstract: The objective of this study was to test three measurements: brain stem (BS), intracranial translucency (IT) and brain stem to occipital bone distance (BSOB), as well as one landmark: cisterna magna (CM) visibility, for early diagnosis of open spina bifida (OSB) in a low risk population. A prospective observational study was undertaken in a university hospital. A sample of 1479 women consented to participate between 20 September 2013 and 30 June 2015. Measurements were performed from the mid-sagittal view, as is routinely used for nuchal thickness assessment. CM visibility was assessed qualitatively as the third anechoic band in the posterior cranial fossa (PCF). All pregnancies were screened with a combination of maternal serum alpha-fetoprotein and second trimester anomaly scan and followed until delivery. Predictive values were calculated for each marker. We were able to diagnose two OSB cases and highly suspect one Dandy-Walker malformation case at the first trimester scan by the observation of PCF. PCF characteristics of OSB cases were increased BS diameter, increased BS-BSOB ratio and non-visualization of the CM. All the markers demonstrated high sensitivity and specificity but CM visibility reached the highest positive predictive value. Due to relatively high false positive rates, PCF measurements could not reach a satisfactory performance to validate their clinical use as a single marker. CM visibility has the advantage of being a qualitative marker and reduces the need for sophisticated and time-consuming measurements. Intracranial translucency and BS-BSOB ratio measurements should be used when the CM visibility is absent or in doubt.
authors.affiliation: Division of Perinatology, Department of Obstetrics and Gynecology, Dokuz Eylul University School of Medicine, Balcova, Izmir, Turkey.
authors.forename: Semir
authors.identifier: http://orcid.org/0000-0001-7621-7503
authors.initials: S
authors.lastname: Kose
authors.affiliation: Division of Perinatology, Department of Obstetrics and Gynecology, Dokuz Eylul University School of Medicine, Balcova, Izmir, Turkey.
authors.forename: Sabahattin
authors.initials: S
authors.lastname: Altunyurt
authors.affiliation: Department of Biostatistics, Dokuz Eylul University School of Medicine, Balcova, Izmir, Turkey.
authors.forename: Pembe
authors.initials: P
authors.lastname: Keskinoglu
mesh_terms: D000293:Adolescent; D000328:Adult; D015415:Biomarkers / Q000097:blood; D001933:Brain Stem / Q000002:abnormalities / Q000000981:diagnostic imaging*; D002946:Cisterna Magna / Q000002:abnormalities / Q000000981:diagnostic imaging*; D003388:Cranial Fossa, Posterior / Q000000981:diagnostic imaging* / Q000473:pathology; D005260:Female; D005865:Gestational Age; D006801:Humans; D008875:Middle Aged; D048208:Nuchal Translucency Measurement; D009777:Occipital Bone / Q000000981:diagnostic imaging* / Q000473:pathology; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D011262:Pregnancy Trimester, Second; D011446:Prospective Studies; D016137:Spina Bifida Cystica / Q000000981:diagnostic imaging / Q000473:pathology*; D016216:Ultrasonography, Prenatal; D000509:alpha-Fetoproteins / Q000378:metabolism
chemical_list: D015415:Biomarkers; D000509:alpha-Fetoproteins
keywords: cisterna magna; fetal posterior cranial fossa; first trimester screening; intracranial translucency; open spina bifida