Guideline sources The following summarized guidelines for the evaluation of fetal central nervous system ultrasound are prepared by our editorial team based on guidelines from the World Association of Perinatal Medicine (WAPM 2021). 1 Guidelines 1. Diagnostic investigations Skull ossification: assess the normal shape of the fetal head/skull and the cranial bone ossification at the anatomy scan by axial scans (trans-thalamic or trans-ventricular planes). E Show 2 more Cerebral hemispheres: Assess the symmetry of hemispheres at the anatomy scan by axial scans (trans-thalamic or trans-ventricular planes). E Assess the presence of a central interhemispheric fissure and a falx dividing equally the hemispheres at the anatomy scan by axial scans (trans-thalamic or trans-ventricular planes). E Lateral ventricles (occipital horns): assess the occipital horn of the lateral ventricle distal to the transducer at the anatomy scan by axial scans (trans-ventricular plane). E Show 2 more Lateral ventricles (frontal horns): assess the presence and orientation of two frontal horns of the lateral ventricles medially separated by cavum septi pellucidi at the anatomy scan by axial scans (trans-thalamic or trans-ventricular planes). E Cavum septi pellucidi: assess the presence of the cavum septi pellucidi at the anatomy scan by axial scans (trans-thalamic or trans-ventricular planes). E https://web.pathway.md/diseases/recrbvB7fkk24RMXx 1/2 6/29/23, 4:05 AM Fetal central nervous system ultrasound Pathway Corpus callosum: obtain median/midsagittal view to directly demonstrate the corpus callosum in terms of presence or absence (complete-partial). E Thalami: assess the presence of two thalami separated from each other in the midline at the anatomy scan by axial scans (trans-thalamic plane). E Insula: consider assessing the presence of a normal developed Sylvian fissure for its shape at the mid-trimester anatomy scan by axial scans (trans-ventricular plane as well as trans- thalamic plane), recognizing that it does not rule out every abnormality. E Cerebellum: assess the presence of normal cerebellar hemispheres joined in the middle by the cerebellar vermis at the anatomy scan by axial scan (trans-cerebellar plane). E Show 2 more Cisterna magna: Assess the presence of a normal cisterna magna at the anatomy scan by axial scan (trans- cerebellar plane). E Measure the cisterna magna at the anatomy scan by axial scan (trans-cerebellar plane). E Spine: assess the presence and regularity of the whole spine (including the sacrum) and integrity of the skin at the anatomy scan by a sagittal scan. E References 1. Valentina De Robertis, Cihat Sen, Ilan Timor-Tritsch et al. WAPM World Association of Perinatal Medicine Practice Guidelines: Fetal central nervous system examination. J Perinat Med. 2021 Jun 4;49 9 1033 1041. Open https://web.pathway.md/diseases/recrbvB7fkk24RMXx 2/2