Antenatal and Postnatal Ultrasound Detection of Vein of Galen Aneurysmal Malformation in a Male Neonate
Year: 2025
Type: article
Study design: Case Report
Abstract: Introduction Vein of Galen aneurysmal malformation (VGAM) is an exceptionally rare cerebrovascular anomaly, occurring in approximately 1 in 25,000 live births. Although it represents less than 1% of all intracranial vascular malformations, it accounts for nearly 30% of pediatric intracranial vascular lesions. Embryologically, VGAM arises between the sixth and eleventh weeks of gestation due to the failure of normal regression of the connection between the median prosencephalic (Markowski) vein and the primitive choroidal vessels, resulting in persistent arteriovenous shunting.1 Normal cerebral vascular development proceeds through three stages: the prechoroidal (stages I and II) and the choroidal (stage III) phases.2 During the choroidal stage, the median vein of Markowski serves as the principal drainage route, while the choroidal arteries supply the developing brain. In normal development, the posterior segment of this vein persists as the vein of Galen, whereas the anterior segment regresses. In VGAM, however, abnormal arteriovenous shunting causes the anterior segment to dilate rather than regress. Based on angioarchitecture, two main types of VGAM have been described: (1) the choroidal type, characterized by a complex nidus-like network involving multiple choroidothalamic arteries, and (2) the mural type, marked by one or more direct arteriovenous fistulas within the wall of the median prosencephalic vein.2,3 Prenatal diagnosis is typically established during the late second or early third trimester using color Doppler and two-dimensional ultrasonography, which reveal a midline cystic structure with turbulent flow. Three-dimensional (3D) power Doppler, used exclusively in the prenatal setting, may further demonstrate turbulent flow within an intracranial lesion and delineate a cystic structure along the midline anterior wall of the third ventricle. Postnatal evaluation primarily relies on ultrasound with spectral and color Doppler, as well as magnetic resonance imaging (MRI), including MR angiography with both arterial and venous time-of-flight sequences. Digital subtraction angiography remains the gold standard, particularly for planning therapeutic embolization. Computed tomography (CT) and CT angiography are generally not recommended due to limited soft tissue resolution and the associated radiation exposure.2,4,5 Clinical observation A 27-year-old female, gravida 1 para 1, at 32 weeks of gestation, married in a non-consanguineous union for four years, presented with unremarkable medical and family histories. She had received regular antenatal care at a tertiary hospital, including infectious disease screening, routine hematological and biochemical tests, and urine analysis, all of which were within normal limits. She was compliant with iron, calcium, and folic acid supplementation, and her antenatal course was free of maternal complications. Standard obstetric ultrasounds were performed at 12, 20, 32, and 38 weeks of gestation, and no abnormalities were detected. A detailed family history, as well as past medical and surgical history, revealed no contributory findings. No family history of vascular or neurological disorders was reported. All procedures were conducted in accordance with institutional ethical standards and approved principles. Although genetic testing was not performed, current literature indicates that VGAM is typically sporadic, with no consistent hereditary pattern or identifiable risk factors.6 The patient was scheduled for a third-trimester ultrasound scan, as the anomaly scan at 20 weeks had shown no abnormality. Antenatal ultrasound was conducted at our tertiary care hospital using Toshiba Xario 100 and Philips Affinity 50 systems. The Toshiba Xario 100 employs advanced beamforming and Aplipure technology to enhance contrast resolution, whereas the Philips Affinity 50 incorporates tissue-specific imaging and precision beamforming. These technological features improve the detection of subtle neurological abnormalities and vascular flow patterns, thereby increasing diagnostic confidence in identifying VGAM. Antenatal B-mode ultrasonography demonstrated a supratentorial midline, well-defined, round, anechoic cystic lesion located posteriorly in the axial plane and inferior to the splenium of the corpus callosum in the sagittal plane (Supplementary Fig. 1, https://links.lww.com/MFM/A103). Color Doppler imaging revealed increased vascularity with a characteristic “yin-yang” sign, consistent with turbulent flow. Feeding arteries originated from the circle of Willis, with drainage into a dilated straight sinus (Supplementary Fig. 2, https://links.lww.com/MFM/A103). Spectral Doppler tracings demonstrated high systolic and diastolic flow velocities, indicating low-resistance arterial flow. The middle cerebral artery peak systolic velocity measured 71 cm/s (1.59 MoM), suggestive of significant arteriovenous shunting (Supplementary Fig. 3, https://links.lww.com/MFM/A103). Anatomical evaluation of other fetal structures was performed, which revealed cardiomegaly with pericardial effusion. This finding indicates the hemodynamic impact of arteriovenous shunting, underscoring the importance of vigilant monitoring for potential cardiac compromise in cases of VGAM. Although standard color Doppler imaging was undertaken, advanced functional assessments such as the Tei Index and cardiovascular profile score (CVPS) could not be performed due to equipment limitations and the absence of fetal cardiac-specific software at our center. Both antenatal and postnatal findings suggested evolving signs of decompensation (Supplementary Fig. 4, https://links.lww.com/MFM/A103). Postnatal neurosonography with color Doppler confirmed high-velocity flow with aliasing within the previously identified anechoic midline lesion, along with an enlarged draining vessel communicating with the straight sinus (Supplementary Fig. 5, https://links.lww.com/MFM/A103). Based on the lesion’s location and imaging characteristics, several differential diagnoses can be excluded. Arachnoid cysts, typically extra-axial (arising within the arachnoid membrane but external to the brain parenchyma) and most often located in the sylvian fissure, do not exhibit vascular flow. Porencephalic cysts, which are intra-axial and usually found in the periventricular white matter or cortical–subcortical regions, similarly lack abnormal hemodynamic features. In contrast, the presence of high systolic and diastolic arterial flow with a characteristic yin–yang flow pattern is a hallmark of arteriovenous fistulas, strongly suggestive of arteriovenous shunting. Other potential considerations, such as choroid plexus cysts, vascular tumors, or intracranial hemorrhage, do not exhibit arteriovenous shunting. In this case, feeding arteries arising from the circle of Willis and draining into an enlarged straight sinus (Supplementary Figs. 2 and 4, https://links.lww.com/MFM/A103) provided further evidence of an arteriovenous malformation. Persistence of the lesion with high vascular flow in the postnatal period excluded transient vascular anomalies. The presence of an enlarged draining vein connected to the straight sinus confirmed a persistent congenital vascular malformation, consistent with VGAM. Thus, the combination of high-flow Doppler patterns, demonstrable arteriovenous shunting, a midline anechoic lesion, and a direct venous connection strongly supported the diagnosis of VGAM. Other differential diagnoses lacked this distinctive vascular pattern and anatomical location, making VGAM the most plausible diagnosis in this case. At 38 weeks of gestation, the patient underwent spontaneous onset of labor and normal vaginal delivery. The intrapartum course was uneventful, with continuous cardiotocographic monitoring demonstrating a reactive fetal heart rate pattern and no signs of distress. A male neonate weighing approximately 3.0 kg was delivered with Apgar scores of 10 at 1 minute and 9 at 5 minutes. Mild intermittent respiratory effort was noted at 6 hours of life, and the infant was admitted to the neonatal intensive care unit for observation in view of transient tachypnea. A neonatal transfontanellar neurosonography was performed the following day using a curvilinear probe via the anterior fontanelle, which confirmed the antenatal ultrasound findings. Following postnatal confirmation of VGAM, the neonate was referred to a tertiary center with pediatric neurosurgical and interventional neuroradiology facilities for further evaluation. The parents opted to proceed directly with treatment without prior MRI evaluation. Endovascular embolization was discussed as a future therapeutic option depending on clinical evolution. Unfortunately, due to financial constraints and treatment delays, the neonate succumbed despite planned follow-up and supportive care. Discussion Our case is consistent with existing literature emphasizing the crucial role of combined prenatal and postnatal imaging in the timely diagnosis of VGAM, enabling clinicians to anticipate complications and plan early management.4 In this patient, prenatal ultrasound identified a well-defined midline cystic lesion with turbulent, low-resistance blood flow on color Doppler, findings strongly indicative of VGAM and useful in excluding other cystic brain lesions.5 The abnormal arteriovenous shunting observed can impose hemodynamic stress on the fetal heart, as evidenced postnatally by cardiomegaly with pericardial effusion, although the neonate did not demonstrate clinical signs of heart failure at birth. Despite prenatal evidence of cardiac stress, the absence of hydrops or fetal instability suggested a compensated state in utero. Postnatal persistence of cardiomegaly, together with mild respiratory distress, indicated early cardiac involvement; however, advanced functional assessment, including the Tei Index, CVPS, or evaluation of aortic steal and tricuspid regurgitation, was not performed due to institutional limitations.2 Differential diagnoses for a midline supratentorial cystic lesion include arachnoid cysts (which lack internal vascular flow on Doppler), Dandy-Walker malformation (typically associated with vermian hypoplasia and a posterior fossa cyst), porencephalic cysts (which communicate with the ventricular system), and pineal region tumors (solid lesions). Among these, arachnoid cysts are particularly relevant due to their similar anechoic appearance; however, they do not demonstrate internal flow or communication with deep venous structures. Color Doppler imaging is pivotal for differentiating VGAM from these entities, confirming the presence of turbulent arterialized venous flow within the lesion and its direct connection to the venous drainage pathways. Modern imaging modalities have substantially enhanced the detection of rare cerebrovascular anomalies such as VGAM. Two-dimensional ultrasound with color and pulsed Doppler remains the primary modality for prenatal diagnosis. However, 3D power Doppler and fetal MRI provide more detailed visualization of cerebral vasculature and associated parenchymal abnormalities, aiding in diagnostic confirmation and informing postnatal care planning.6 Effective management of VGAM necessitates a multidisciplinary approach. In this case, neonatologists, pediatric cardiologists, neurologists, and radiologists collaborated to determine the optimal course of action. Although symptomatic intervention was not immediately required, the neonate was referred for specialized neurovascular evaluation, with endovascular embolization considered if hemodynamic compromise arose. Long-term follow-up was arranged to monitor potential neurodevelopmental complications. Conclusion Overall, this clinical observation highlights the critical role of detailed prenatal and postnatal imaging in the timely diagnosis and management of VGAM. Integration of advanced Doppler studies with confirmatory neonatal neurosonography and supportive clinical findings facilitated early recognition and provided insight into the hemodynamic consequences of this rare vascular anomaly. Future studies should aim to delineate long-term outcomes and refine management strategies to optimize perinatal care for affected neonates. Funding None. Author Contributions Shreya Tapadia, Varun Singh, Gurbaksh Singh Soni, Isha Tripathi, and Rudransh Ghogare contributed to the preparation, organization, writing, and editing of all sections of the manuscript. Shreya Tapadia was responsible for creating all figures included in the manuscript. Additionally, Shreya Tapadia contributed to the study conception and design, data acquisition, analysis, and interpretation. All authors contributed equally to manuscript preparation and reviewed and approved the final version prior to submission. Conflicts of Interest None. Data Availability The datasets generated during and/or analyzed during the current study are available from the corresponding author on reasonable request.
Source: Maternal-Fetal Medicine
Authors: Shreya Tapadia, Varun Singh, Gurbaksh Singh Soni, Isha Tripathi, Rudransh Bhausaheb Ghogare
Language: English
Subfield: Neurology
Field: Medicine
Domain: Health Sciences
Open Access status: diamond
OpenAlex ID: W4415406754