ASA 2022 Melbourne Conference - Neonatal Neurosonography

Summary

In this informative lecture, Henry delves into neonatal neural sonography, covering the essentials of technique, anatomy, and pathology. He highlights the importance of probe selection and scanning approaches, then transitions into a detailed exploration of neonatal brain pathologies, including hemorrhage grading, hydrocephalus, and various congenital anomalies. The presentation is a valuable resource for medical professionals seeking to enhance their understanding of neonatal brain ultrasounds.

Takeaways

• 🌟 Neonatal neural sonography is divided into two main sections: basic technique and anatomy, and pathology.
• 🔍 High-frequency transducers are essential for neonatal neural sonography to ensure good image resolution, with micro-convex array transducers being the speaker's preferred choice.
• 👶 Indications for neonatal cranial ultrasound include prematurity, low Apgar scores, neurological changes, cranial dysmorphisms, and follow-up for known hemorrhages or other pathologies.
• 📚 Key sonographic features to learn include the inter-hemisphere fissure, sylvian fissures, cavum septum pellucidum, corpus callosum, basal ganglia, ventricular system, and cerebellum.
• 🧠 The cavum septum pellucidum is a fetal neural developmental marker that is normally present and can be associated with CNS anomalies if absent.
• 🔑 The corpus callosum is the largest white matter structure, connecting both hemispheres of the brain and playing a role in eye movement, cognition, and tactile localization.
• 🚫 Germinal matrix hemorrhages typically occur in the sub-ependymal region and are a significant concern due to their potential to cause severe neurological deficits.
• 🌐 The ventricular system, consisting of the lateral, third, and fourth ventricles, is essential for the circulation of cerebrospinal fluid and can be affected by various pathologies.
• 💉 The extra-axial spaces are important for identifying collections such as subdural or epidural hemorrhages, and benign enlargement of the arachnoid spaces.
• 🔍 Scanning techniques involve using the anterior fontanelle for obtaining coronal and sagittal views, with attention to detail to avoid missing critical findings.
• 🩸 Intraventricular hemorrhage (IVH) is a primary concern in neonatal brain ultrasounds, especially in extremely premature infants, and is graded from one to four, with grade four being the most severe.

Q & A

What are the two main sections covered in Henry's lecture on neonatal neural sonography?

The two main sections covered in Henry's lecture are the basics of neonatal neural sonography, which includes technique, anatomy, and the second section on pathology.

What type of transducer does Henry recommend for neonatal neural sonography?

Henry recommends using a high-frequency transducer for good resolution in neonatal neural sonography, with a preference for micro-convex array transducers that usually range from three to ten megahertz.

What are the primary indications for neonatal cranial ultrasound?

The primary indications for neonatal cranial ultrasound include prematurity, low Apgar scores, any neurological changes upon or during admission, cranial dysmorphisms such as macrocephaly or microcephaly, craniosynostosis, and follow-up for known hemorrhages or other pathologies.

What is the cavum septum pellucidum and why is it significant in neonatal sonography?

The cavum septum pellucidum is a midline cystic structure between the anterior horns of the lateral ventricles and is a fetal neural developmental marker. It is present in normal brains and its absence has been associated with central nervous system anomalies like septo-optic dysplasia, holoprosencephaly, and agenesis of the corpus callosum.

What is the significance of the corpus callosum in the brain and what does it consist of?

The corpus callosum is a horizontal bundle of nerve fibers that connects both hemispheres of the brain and is the largest white matter structure, consisting of over 200 million axons. It plays a crucial role in eye movement, cognition, and tactile localization.

What is the germinal matrix, and why is it important in neonatal brain scans?

The germinal matrix is a highly vascularized thin membrane located in the sub-ependymal region of the cytothalamic groove. It is important because it is the starting point for germinal matrix hemorrhages, which can occur in premature infants.

What are the key features of the ventricular system in the brain, and why are they important in neonatal sonography?

The ventricular system consists of the lateral ventricles, the third ventricle, and the fourth ventricle. These are chambers filled with cerebrospinal fluid and contain the choroid plexus, which creates the fluid. They are important in neonatal sonography to check for abnormalities such as hydrocephalus or hemorrhages.

What is the significance of the extra axial spaces in neonatal sonography?

The extra axial spaces are important in neonatal sonography because they can have collections from benign enlargement of the arachnoid spaces, which is a common cause of microcephaly, up to and including subdural or epidural hemorrhages.

Can you explain the grading system for intraventricular hemorrhages (IVH) in neonatal patients?

The grading system for IVH consists of four grades. Grade one is the least severe, with bleeding contained within the germinal matrix. Grade two indicates bleeding has broken into the ventricle but occupies less than 50% of the ventricular space without ventricular dilatation. Grade three involves bleeding occupying more than 50% of the ventricle or causing ventricular enlargement. Grade four is the most severe, characterized by intraparenchymal or periventricular hemorrhage within the brain tissue itself.

What are some risk factors for intraventricular hemorrhage in neonatal patients?

Risk factors for intraventricular hemorrhage include prematurity (less than 32 weeks, especially if extreme, and less than 1500 grams), rapid fluctuations in blood pressure or blood volume, transfer from outside facilities, coagulopathy or blood clotting disorders, respiratory distress, and hypoxic ischemic events.