Prenatal diagnosis of fetal dural arteriovenous fistula using two-dimensional ultrasound and spatiotemporal image correlation technology: a case description

Introduction

Dural arteriovenous fistulas (DAVFs), also known as dural arteriovenous shunts, are abnormally acquired intracranial vascular malformations consisting of pathological connections located in the dura between the pial arteries and the venous sinuses (1,2). The true incidence of intracranial DAVFs is not known; however, reported DAVF cases account for 10–15% of all diagnosed intracranial vascular malformations (2).

DAVFs can result in hydrocephalus, heart failure, and fetal demise. Timely prenatal identification and management of DAVFs are crucial. While the prenatal detection of DAVFs is uncommon, diagnostic accuracy has increased with advances in imaging modalities (3).

Recently, three-dimensional (3D) Doppler and intrauterine magnetic resonance imaging (MRI) have become common in diagnosing fetal vascular malformations. 3D Doppler technology offers detailed blood flow imaging for the precise assessment of these malformations, while MRI provides in-depth tissue imaging to evaluate the extent of the malformations. Nevertheless, challenges persist in using these methods for the prenatal diagnosis of fetal DAVFs (4).

Spatiotemporal image correlation (STIC) technology, derived from 3D ultrasound, improves the visualization of intricate fetal vascular structures by using dynamic volume data and 3D reconstruction techniques. When combined with Doppler ultrasound, STIC enables more precise hemodynamic evaluations and enhances diagnostic precision (5). While STIC technology is widely used to diagnose fetal cardiovascular malformations, research on its application in the diagnosis of fetal DAVFs is limited.

We combined two-dimensional (2D) ultrasound with STIC for the prenatal diagnosis of fetal DAVF. This case report shows the diagnostic utility of this combined approach for complex vascular abnormalities.

Case presentation

All procedures performed in this study were in accordance with the ethical standards of the institutional and/or national research committee(s) and with the Declaration of Helsinki and its subsequent amendments. Written informed consent was provided by the pregnant mother for publication of this article and accompanying images. A copy of the written consent is available for review by the editorial office of this journal.

A 38-year-old pregnant woman (gravida 3, para 2), with no significant medical or family history of genetic disorders, was referred to Gansu Provincial Maternity and Child-care Hospital due to the detection of fetal cardiac abnormalities. The GE Healthcare Voluson E10 ultrasound system (Chicago, IL, USA), equipped with a high-resolution 3D/four-dimensional transducer, was used for the ultrasound examinations. The STIC acquisition was performed using standard fetal heart imaging protocols at 39+1 weeks of gestation, with dynamic volumetric data captured at a frame rate of 24 frames per second. The sector angle was set to 70°, and the image resolution was optimized to 0.4 mm in both the lateral and axial directions. No abnormalities were detected during early pregnancy.

The ultrasound findings of the fetal abnormalities in late pregnancy are detailed in Figure 1. Prenatal ultrasound at 39+1 weeks revealed an increased cardiothoracic ratio (0.71), ventricular wall thickening, significant bilateral internal jugular vein dilation (Figure 1F), and reversed flow in the aortic arch, with an abnormal, tortuous alignment of the arterial duct. Follow-up imaging revealed an echogenic area measuring approximately 15 mm × 7 mm above the cerebellar tegmentum (Figure 1A), with color Doppler flow imaging revealing active blood flow in the region. The Pulsatility Index value of the middle cerebral artery was reduced (approximately 0.72). Tortuous intracranial arteries with reduced flow velocity and abnormal arteriovenous communication were observed, with an arterial spectrum detected on pulsed Doppler (Figure 1C). The dural sinuses, including the sinus confluence, straight sinus, and transverse sinus, were significantly dilated, with a maximum internal diameter of 8 mm (Figure 1B,1E).

Figure 1 Prenatal ultrasound image of DAVFs. (A) An echogenic area of approximately 15 mm × 7 mm was observed above the cerebellar tegmentum. (B) Two-dimensional ultrasound revealed significant dilation of the dural sinuses, including the sinus confluence, straight sinus, and transverse sinus. (C) Tortuous intracranial arteries with reduced flow velocity and abnormal arteriovenous communication were observed, with an arterial spectrum detected using pulsed Doppler. (D) Spatiotemporal image correlation imaging confirmed the presence of abnormal intracranial arteriovenous connections. (E) Color Doppler ultrasound again showed significant dilation of the dural sinuses, including the sinus confluence, straight sinus, and transverse sinus. (F) Color Doppler ultrasound revealed a dilated internal jugular vein.

STIC further confirmed the presence of abnormal intracranial arteriovenous connections (Figure 1D). The ultrasound diagnosis suggested a fetal DAVF, with generalized cardiac enlargement (particularly of the right heart), marked dilation of the bilateral internal jugular veins, reversed flow in the aortic arch, and abnormal arterial duct alignment. After discussion among the maternal-fetal medicine, neonatology, pediatric cardiology, and neurosurgery teams, the decision was made to defer delivery until full term, given the fetus’s stable hemodynamics to avoid prematurity-related risks.

Post-delivery at 39+5 weeks, neonatal cranial ultrasound demonstrated that part of the intracranial arterial blood flow directly converged into the superior sagittal sinus at low velocity. Additionally, the straight sinus and sinus confluence appeared significantly narrower compared to the fetal period (Figure 2A,2B). Subsequent ultrasound evaluation confirmed a diagnosis of a DAVF. MRI revealed an enlargement of the right transverse sinus. (Figure 2C,2D), confirming the diagnosis of a DAVF.

Figure 2 Postpartum ultrasound and MRI images of DAVF. (A,B) Neonatal cranial ultrasound showed significant narrowing of the straight sinus and sinus confluence post-delivery compared to the prenatal ultrasound findings. (C,D) Magnetic resonance imaging revealed an enlargement of the right transverse sinus.

The patient received aggressive treatment and was closely monitored. At birth, the infant displayed signs of high-output cardiac failure consistent with the prenatal diagnosis, prompting immediate medical management, including careful fluid control and beta-blocker therapy (propranolol), to stabilize cardiac function. Early postnatal neuroimaging and neurosurgical evaluation were also performed; however, no urgent intervention was required as the DAVF demonstrated spontaneous partial regression on serial follow-up imaging. Notably, the detailed prenatal ultrasound findings directly informed these perinatal management decisions, guiding the optimal timing of delivery and preparing the clinical team for targeted neonatal therapy and monitoring, thereby underscoring the critical value of early diagnosis in improving outcomes. At the 12-month postnatal follow-up, the child exhibited normal development with no notable complications.

Discussion

DAVF is a rare cerebrovascular malformation characterized by direct connections between dural arteries and dural venous sinuses or cortical veins, bypassing the normal capillary bed (6). Its pathogenesis remains incompletely understood, but it is generally believed to result from a combination of embryologic vascular dysgenesis and secondary changes such as venous sinus thrombosis. Abnormal persistence or the reopening of primitive arteriovenous channels during fetal development may lead to fistula formation. In some cases, increased venous pressure from early thrombosis may stimulate angiogenic factors, promoting the development of arteriovenous shunts. These vascular abnormalities can disrupt cerebral hemodynamics, potentially leading to venous hypertension, cerebral edema, hydrocephalus, or high-output cardiac failure (7).

In the present case, prenatal 2D ultrasound identified a well-circumscribed, anechoic-to-hypoechoic lesion in the posterior cranial fossa, with prominent vascular flow signals on color Doppler imaging. No obvious hydrocephalus, parenchymal destruction, or intracranial hemorrhage was observed at the time of examination. These imaging features are consistent with the typical prenatal presentation of DAVF, and differentiation from other cerebral vascular anomalies, such as vein of Galen aneurysmal malformation (VGAM), relies on the detailed evaluation of vascular anatomy and drainage patterns.

Historically, the prenatal diagnosis of cerebrovascular malformations has relied on 2D ultrasound combined with color and spectral Doppler. These techniques provide valuable real-time information on the size, location, and flow characteristics of vascular lesions. However, their limitations include a restricted field of view, operator dependency, and difficulty in assessing complex 3D spatial relationships. Fetal MRI can provide complementary anatomical detail, particularly for evaluating associated brain parenchymal injury; however, it lacks real-time hemodynamic information and may be limited in detecting fast-flow vascular shunts.

In this case, STIC was applied to enhance the diagnostic evaluation. STIC enabled the acquisition of a high-resolution volumetric dataset of the fetal brain with color Doppler imaging over several cardiac cycles. This dataset allowed for the offline, multiplanar, and dynamic reconstruction of cerebral vascular structures (8). With STIC, the origin, course, and connections of the feeding arteries and draining veins were more clearly visualized, and the direct arteriovenous communication characteristic of the DAVF was confirmed. Importantly, the ability to analyze the vascular anatomy from multiple angles helped distinguish the lesion from VGAM and other differential diagnoses.

STIC offers several distinct advantages in the prenatal evaluation of complex vascular malformations. It provides dynamic, time-resolved volumetric data that can be reviewed offline, reducing reliance on real-time operator expertise. The synchronized display of fetal cardiac cycles enables improved visualization of blood flow direction and velocity, which is particularly useful in detecting arteriovenous shunts. Further, STIC enhances spatial resolution and enables the 3D analysis of intricate vascular networks. These advantages contribute to more accurate diagnosis, facilitate multidisciplinary decision making, and improve prenatal counseling regarding prognosis and postnatal management options.

The clinical significance of fetal DAVF depends largely on its size, location, and associated complications. In severe cases, high-flow shunts can lead to venous congestion, potentially resulting in fetal hydrops or heart failure. If a DAVF is detected early in pregnancy, it provides an opportunity for close monitoring and, in some cases, intervention. However, the prognosis remains highly variable; smaller lesions with well-preserved cerebral parenchyma may result in favorable outcomes, while large or complex DAVFs with significant venous drainage may lead to adverse outcomes, such as brain malformations or stillbirth. Moreover, DAVFs may have long-term neurological consequences even in postnatal life, particularly if untreated or undiagnosed. In this case, the fetus was observed to have a relatively isolated DAVF with no immediate signs of hydrocephalus or significant brain damage at the time of ultrasound. The clinical decision was made to closely monitor the condition and follow up with serial imaging.

The management of fetal DAVFs remains largely conservative, particularly in cases in which the lesion does not cause significant hemodynamic disturbance or neurological compromise. Interventions are generally reserved for cases in which there is a substantial risk of high-output cardiac failure, hydrops, or other complications. Options for fetal intervention include embolization of the fistula or, in some instances, surgical resection after birth. In the present case, given the lack of severe fetal complications, management was primarily observational. The fetus was closely monitored for signs of cardiovascular instability, and regular follow up with ultrasound was performed to assess the progression of the DAVF. As there were no signs of associated brain damage or hydrocephalus, the focus remained on managing the fetal heart condition, which had been diagnosed concurrently, rather than a direct intervention on the DAVF.

Fetal DAVFs must be differentiated from similar lesions such as VGAMs, arachnoid cysts, Dandy-Walker malformations, and simple ventricular dilatation or hydrocephalus during prenatal diagnosis (9). VGAMs typically occur in the midline, while DAVFs are generally found in non-midline locations. VGAM is characterized by the arterialization of the veins of Galen with dilation of the venous sinuses, whereas DAVF manifests as localized venous fistulas and dilated peripheral venous lakes. Arachnoid cysts and Dandy-Walker malformations do not exhibit abnormal arteriovenous communication on color Doppler imaging, although they may also appear as echogenic areas in the posterior cranial fossa. In cases of secondary ventricular dilation, it is essential to distinguish it from simple hydrocephalus. Color Doppler imaging can distinguish simple hydrocephalus from arteriovenous fistulas associated with hemodynamic abnormalities, enhancing the accuracy of differential diagnosis.

Most prenatally diagnosed fetal DAVFs have the potential for spontaneous regression and a relatively favorable prognosis, with patients often achieving normal neurodevelopmental outcomes. In this case, the child experienced postpartum global enlargement and cardiac insufficiency, but gradually recovered with intensive treatment and showed no significant complications at the 12-month follow-up, with clinical and imaging assessments indicating normal cognitive, motor, and social developmental milestones for the child. Echocardiography revealed the resolution of cardiac enlargement with normalized ventricular function. Cranial ultrasound showed persistent but stable narrowing of previously dilated dural sinuses without evidence of new or progressive vascular malformations. This emphasizes the relatively favorable prognosis following timely diagnosis and comprehensive neonatal management.

The exact classification of the lesion remains uncertain, as its features overlap with multiple types of dural arteriovenous shunts. While STIC imaging provided valuable insights into the lesion’s anatomy, its role in definitive classification is limited due to the complexity and variability of these malformations. Additionally, the absence of genetic testing in this study represents another limitation. Future research should incorporate genetic testing and long-term follow-up to better understand the etiology, prognosis, and underlying genetic risks, which could improve prenatal counseling and inform postnatal surveillance strategies.

Conclusions

This case demonstrates that combining 2D ultrasound with STIC technology significantly improves the prenatal diagnostic accuracy of fetal DAVF. The dynamic and volumetric capabilities of STIC allow for a more comprehensive evaluation of intracranial vascular anatomy and hemodynamics, supporting early and reliable diagnosis. This is essential for prenatal counseling, delivery planning, and postnatal intervention strategies. As a non-invasive and accessible imaging modality, STIC holds great promise for improving the prenatal detection of rare but clinically significant cerebrovascular anomalies. Further research involving larger case series is needed to establish standardized imaging protocols and validate the clinical utility of STIC in prenatal neurosonography.

Acknowledgments

None.

Footnote

Funding: This study was supported by the National Natural Science Foundation of China (No. 62027827) and the Project for Cultivating Young Talents in Gansu Province (No. GSWSQNPY-2024-05).

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://qims.amegroups.com/article/view/10.21037/qims-2025-755/coif). The authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. All procedures performed in this study were in accordance with the ethical standards of the institutional and/or national research committee(s) and with the Declaration of Helsinki and its subsequent amendments. Written informed consent was provided by the pregnant mother for publication of this article and accompanying images. A copy of the written consent is available for review by the editorial office of this journal.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

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