Fetal neurology – diagnosis and counseling

Administrator: Tally Lerman-Sagie, Israel

Prof. Tally Lerman-Sagie

Fetal Neurolgy Clinic and Pediatric Neurology Unit, Wolfson Medical Center, Holon, Israel and Sackler School of Medicine Tel-Aviv University, Israel

tally.sagie@gmail.com

The Fetal Neurology Clinic

Fetal Neurology expands the field of pediatric neurology to fetal life. Fetal Neurology Clinics (FNC) are multidisciplinary and involve: Paediatric Neurology, Radiology, Genetics and fetal Pathology.
After gaining experience in the diagnosis of relatively common anomalies such as ventriculomegaly, agenesis of the corpus callosum, infections and other acquired insults, it became apparent that the confronted tasks were complicated and involved: difficulties in early diagnosis in a brain that is rapidly evolving and changing; counselling parents following late diagnoses during the 3rd trimester; inability to accurately prognosticate in poorly defined or equivocal cases; implementation of knowledge acquired from postnatal studies to prenatal life; and counselling parents with diverse values and beliefs.
Most of the cases are referred by obstetricians who suspect a CNS anomaly. The initial diagnosis is confirmed, or modified based on a detailed neurosonographic examination, using the transvaginal approach; the examination is complemented with fetal MRI. When an anomaly is detected a complete reexamination of fetal anatomy is essential, since the diagnosis of associated anomalies is invariably a factor that worsens the prognosis.
Following the diagnosis of a CNS anomaly the team discusses the case based on their accumulating knowledge and the current literature. An agreement is reached and then the parents are counselled regarding the evaluation and possible prognosis.

Dr Ivana Pogledic

Department of Biomedical Imaging and Image-guided Therapy, Vienna General Hospital, Vienna, Austria

ivana.pogledic@meduniwien.ac.at

Development of the fetal brain

The fetal cortex develops during pregnancy from a smooth surface at the first half of
pregnancy, into a complex array of sulci and gyri by the end of gestation. Dedicated
neurosonography and fetal MRI enable accurate depiction of the developing fetal cortex.
The appearance of the main fissures, sulci and gyri on axial, coronal, and sagittal views have been evaluated in intervals from the 18th week of pregnancy until term, and figures have been developed that are helpful for neurosonographers and radiologists who assess cortical development.
All studies confirm that the major fissures and sulci (Sylvian, inter-hemispheric, callosal, and hippocampal) are already present at 18 and 20 weeks. The period between 22 and 26 weeks is characterized by the gradual development of the parieto-occipital, calcarine cingulate and
central sulcus. The most active period of cortical development is between 28 and 30 weeks.
After 32 weeks most sulci become detectable. At late third trimester, the frontal, Sylvian, and occipital sulci are best demonstrated on coronal planes, whereas upper convexity sulci on the sagittal ones.

Prof Gregor Kasprian

Department of Biomedical Imaging and Image-guided Therapy, Vienna General Hospital, Vienna, Austria

gregor.kasprian@meduniwien.ac.at

The role of brain MRI in diagnosis and counselling of fetuses with brain anomalies

Although ultrasound is the predominant modality for evaluating disorders in pregnancy, fetal MRI is increasingly used and considered a complementary technology. Fetal MRI is not limited by fetal position, obesity or oligohydramnios and visualization of the brain is not restricted by the ossified skull. With its higher resolution, contrast abilities, as well as a large field of view, MRI facilitates the examination of fetuses with large or complex anomalies as well as visualization of lesions within the context of the entire fetal body.
Indications for fetal MRI include confirmation of inconclusive sonographic findings and evaluation of sonographically occult diagnoses. Indications may vary widely, as a consequence of the different states of experience of the sonographers and the specialties of the respective perinatal center.
Malformations of the CNS are difficult to characterize prenatally. In tertiary referral centers with expert neurosonographers, fetal MRI has been shown to be advantageous with respect to clinical counseling of cases with CNS malformations.
The most common referrals include disorders of cortical malformation, commissural abnormalities, ventriculomegaly, infratentorial pathologies and acquired pathologies.
With a systemic approach, and thorough knowledge of the developing brain, fetal MRI is effective in the detection of subtle brain abnormalities and as well as complex lesions. Fetal MRI helps in patient management and counselling.

Prof. Ilan Timor

NYU School of Medicine Department of Ob/Gyn, New-York, USA

ilan.timor@nyumc.org

The role of dedicated neurosonography in diagnosis and counselling of fetuses with brain anomalies

Dedicated neurosonography is a targeted, detailed US performed by advanced machines and technology read by experienced US practitioners. It is not synonymous with the 2nd trimester routine screening of general fetal anomaly using three axial planes. Targeted fetal neurosonography has a much greater diagnostic potential for evaluation of complex malformations.The transvaginal approach is the preferred method. A systematic evaluation of the brain usually includes visualization of axial, coronal and sagittal planes.
Advanced neuroimaging and genetics, as well as the publication of longer-term prognostic studies, have led to fetal neurology becoming an essential part of prenatal obstetric care. Common conditions seen are ventriculomegaly, agenesis of the corpus callosum and posterior fossa anomalies. The prognosis frequently depends on the severity of the condition and the presence of other anomalies. Certain pathologic processes, such as myelomeningocele, can be treated surgically in the prenatal period, and there is ongoing research regarding potential treatments of other conditions such as tuberous sclerosis. Acquired conditions such as hemorrhage, tumor, and ischemic stroke can also be seen prenatally, and their early diagnosis may inform postnatal care.Neurologists now play an important role in prognostication, medical care, and decision-making during pregnancy.