Problem-Based Obstetric Ultrasound

Amar Bhide, Asma Khalil, Aris T. Papageorghiou, Susana Pereira, Shanthi Sairam, Basky Thilaganathan, Amar Bhide, Asma Khalil, Aris T. Papageorghiou, Susana Pereira, Shanthi Sairam, Basky Thilaganathan

• Publisher: CRC Press
• Year: 2019
• eBook ISBN: 9780429530579
• Edition: 2
• Topic: Medicine
• Subtopic: Gynecology, Obstetrics & Midwifery

This book contains a series of clinical cases that address and illustrate difficult problems in obstetric ultrasound. The approach is strongly didactic and will aid trainees in maternal-fetal medicine and obstetrics to appreciate potential pitfalls and recognize rare presentations. Each case sets out one page of text, then one of treatment algorithms, and then presents sample ultrasound scans. Learning objectives are given for each case, together with a short list of references and background reading.

1

Ventriculomegaly

The lateral ventricles should be measured at the routine mid-trimester scan in the axial plane at the level of the cavum septi pellucidi, with the calipers aligned with the internal borders of the medial and lateral walls of the ventricle; this should be at the level of the glomus of the choroid plexus. Fetal ventriculomegaly is characterized by a dilatation of the lateral ventricles, with or without dilatation of the third or fourth ventricles. There is no internationally agreed upon terminology, but Table 1.1 shows two systems used. It can affect one (unilateral) or both ventricles (bilateral).

Table 1.1 Different classifications of ventriculomegaly used in the literature
Normal measurement: <10 mm	Normal measurement: <10 mm
Mild ventriculomegaly: 10–12 mm	Mild ventriculomegaly: 10–15 mm
Moderate ventriculomegaly: 12–15 mm
Severe ventriculomegaly: >15 mm	Severe ventriculomegaly: >15 mm

When mild or moderate, it may be due to normal variation, but it also represents a common endpoint of various pathologic processes. As the outcome and prognosis depend on the underlying cause, investigations are aimed at determining this.

Apart from the underlying etiology and the presence of associated structural/chromosomal anomalies, post-natal outcome depends on the progression of ventricular dilatation. In isolated abnormality (absence of pathology and progression), the outlook for mild ventriculomegaly (<15 mm) is good with >95% of babies having normal neurodevelopment.

Associated major anomalies (cranial and extracranial) can be present in 50% of fetuses with VM, of which the most common are agenesis of the corpus callosum, posterior fossa malformations, and open spina bifida. The rate of associated anomalies in severe VM is higher than in mild VM.

Investigations needed

The prognosis is highly dependent on:

•Other fetal anomalies

•The cause of the ventriculomegaly

•Progression of the ventriculomegaly

Investigations are therefore centered around these issues:

•Optimal imaging is needed: undertake (or refer for) detailed multiplanar neurosonography; transvaginal scanning is helpful. This should include assessment of:

•The entire ventricular system

•The periventricular zone/signs of hemorrhage

•The pericerebral spaces and cortical fissures

•Consider fetal MRI.

•Review nuchal translucency and any previous chromosomal anomaly screening or prenatal diagnosis results.

•Consider karyotype by amniocentesis.

•Maternal serology for toxoplasma/CMV infection.

•Platelet group of parents to look for alloimmune thrombocytopenia should be considered if there is any possibility there could be intracranial bleeding.

•Follow up with further scans in the third trimester to assess for progression: It is important to explain to parents that prenatal imaging cannot completely rule out associated anomalies and that some may become evident only later in pregnancy or even at birth. The rate of associated anomalies detected only at follow-up scan is around 7%; progression of ventricular dilatation can occur in about 16% of cases.

Bibliography

Carta S, Kaelin Agten A, Belcaro C, Bhide A. Outcome of fetuses with prenatal diagnosis of isolated severe bilateral ventriculomegaly: Systematic review and meta-analysis. Ultrasound Obstet Gynecol. 2018 Aug; 52(2):...

Table of contents

• Cover
• Half Title
• Series Page
• Title Page
• Copyright Page
• Contents
• 1. Ventriculomegaly
• 2. Intracranial Cysts
• 3. Agenesis of Corpus Callosum
• 4. Abnormal Skull Shape
• 5. Facial Clefts
• 6. Micrognathia
• 7. Nasal Bone
• 8. Hypertelorism
• 9. Chest Tumors
• 10. Chest Fluid
• 11. Right-Sided Aortic Arch
• 12. Aberrant Right Subclavian Artery
• 13. Dextrocardia
• 14. Abnormal Four-Chamber View
• 15. Abnormal Cardiac Rhythm
• 16. Abdominal Wall Defect
• 17. Abdominal Cyst
• 18. Abdominal Echogenicity
• 19. Empty Renal Fossa
• 20. Cystic Kidney
• 21. Fluid-Filled Kidney
• 22. Echogenic Kidneys
• 23. Enlarged Bladder
• 24. Short Limbs
• 25. Joint Abnormalities
• 26. Hand Abnormalities
• 27. Spinal Abnormalities
• 28. Spinal Masses
• 29. Head and Neck Masses
• 30. Increased Nuchal Translucency
• 31. Placental Abnormalities
• 32. Single Umbilical Artery
• 33. Oligohydramnios and Anhydramnios
• 34. Polyhydramnios
• 35. Amniotic Bands
• 36. Abnormally Invasive Placenta
• 37. Hydrops
• 38. Small Fetus
• 39. Twin-to-Twin Transfusion Syndrome
• Index