title: Ultrasound screening for spina bifida: cranial and cerebellar signs.
abstract: Ultrasound records were examined retrospectively in the cases of 70 fetuses with open spina bifida diagnosed by ultrasonography at 16-23 weeks' gestation. Biparietal diameter was below the 5th centile for gestation in 61% and head circumference measurements in 26%. The anterior horn of the lateral cerebral ventricle to hemisphere ratio was above the 95th centile in 77%, and ventriculomegaly of the posterior horn of the lateral venricle was observed in 86%. In the 54 fetuses for which pictures were taken at the level of the biparietal diameter a scalloping of the frontal bones (the lemon sign) was seen. In 12 of 21 fetuses for which a suboccipital bregmatic view of the cranium had been obtained, the cerebellar hemispheres were curved anteriorly with simultaneous obliteration of the cisterna magna (the banana sign); in a further 8 cases the cerebellum was not displayed. None of these changes was seen in 100 patients presenting consecutively for routine ultrasound examination in the second trimester.
mesh_terms: D001139:Arnold-Chiari Malformation / Q000175:diagnosis; D002531:Cerebellum / Q000473:pathology*; D005260:Female; D005315:Fetal Diseases / Q000175:diagnosis*; D006801:Humans; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D011296:Prenatal Diagnosis; D012189:Retrospective Studies; D012886:Skull / Q000473:pathology*; D016136:Spina Bifida Occulta / Q000175:diagnosis*; D014463:Ultrasonography / Q000379:methods; D000509:alpha-Fetoproteins / Q000097:blood
chemical_list: D000509:alpha-Fetoproteins