Evaluation of Vein of Galen Malformations in Children

Examination

Relevant physical exam findings include (39,41,48-50,64):

• Signs of high-output heart failure: The signs of high-output failure include cyanosis, systolic cardiac murmur, hyperdynamic precordium, bounding carotid pulses, and manifestations of organ dysfunction.
• Signs of pulmonary hypertension: These include tachypnea, dyspnea, and feeding intolerance.
• Signs of altered cerebral hemodynamics and/or cerebral venous hypertension: These include cranial bruit, prominent facial veins, and signs of hydrocephalus, including macrocephaly and focal neurological (including cranial nerve) deficits.
• Other physical exam findings that may manifest after neonatal period: These include proptosis and epistaxis.

Laboratory Tests

Key laboratory tests for evaluation of a patient with VOGM assess for organ dysfunction and metabolic abnormalities. Order the following (24,57):

BNP: This blood test is elevated in cases of heart failure.
Renal function tests: These include serum creatinine and BUN and will show signs of kidney failure if it is present.
Liver function tests: These include hepatic transaminases and coagulation factor levels and will be abnormal when there is liver failure.
CBC: This may reveal polycythemia in the setting of chronic hypoxemia due to cardiac compromise. This test also confirms adequate platelet counts for safe embolization.
Lactic acid: This blood test is used to assess the presence of lactic acidosis.

Radiologic Tests

Regular x-rays, ultrasound, etc.

• Prenatal ultrasound: Prenatal ultrasound can be employed to detect VOGM in utero; the saccular lesion appears as an anechoic, midline mass posterior to the third ventricle (65,66).
• Postnatal cranial ultrasound: Postnatal cranial ultrasound can be used to confirm a lesion detected in utero, diagnose a lesion that was not detected via prenatal ultrasound, or characterize hemodynamic patterns within the VOGM (via Doppler ultrasonography) (67). It will also document hydrocephalus when present.

Cranial ultrasound: Cranial ultrasound demonstrated the anechoic, midline mass characteristic of VOGM (red star).

• Chest x-ray: Chest x-ray may reveal cardiomegaly with right atrial and right ventricular enlargement, widening of the superior mediastinum due to dilation of the great vessels, and retropharyngeal soft tissue prominence due to dilation of the carotid arteries and jugular veins (41,68,69)
• Cerebral angiography: DSA is the gold standard for evaluation of the arterial feeders and venous drainage of VOGMs (39,68).

Cerebral angiography with DSA (lateral views): Selective injection of the right ICA in a neonate with VOGM revealed a large PCA feeder (left image; yellow arrow) with two flow streams, resulting in opacification of the dilated median prosencephalic vein (right image).

Cerebral angiography with DSA: Selective injection of the left vertebral artery revealed the large right PCA feeder (yellow arrows) in AP (left) and lateral (right) views.

Video of DSA for VOGM evaluation: Selective injection of the right ICA revealed arterial feeders, the VOGM itself, and the falcine sinus draining into a dilated torcula.

CT scans

• CT: Now typically supplanted by MR imaging and ultrasonography, CT may reveal a round mass in the quadrigeminal cistern posterior to the third ventricle, which may be displaced anteriorly (68). This modality can also reveal thrombosis or calcification of the lesion (39). Limit radiation exposure in young children.

MRI

• MRI: MRI eliminates the risk of radiation exposure and can be employed in the initial evaluation of VOGMs (39). It enables high-resolution characterization of the lesion, including inspection of the location and size of the malformation, identification of abnormalities of the venous sinuses, and identification of possible arterial feeders (39,68). Fetal MRI may be used to evaluate a lesion in utero.
• MRA: MRA is noninvasive, does not expose the patient to radiation, and can be performed without contrast, making it a valuable imaging modality in neonates; however, cerebral angiography is superior in its ability to delineate small arterial feeders and characterize the venous drainage (68). Thus, MRA may play a role in the initial evaluation of VOGM, but cerebral angiography is still required, typically integrated into interventional procedures (39).

MRI: Sagittal T1-weighted MRI depicts a VOGM (red star) in a neonate and associated aqueductal stenosis (yellow arrow).

Fetal MRI: Fetal MRI (axial view) reveals the dilated midline sac (red star) characteristic of VOGM. Its drainage via the falcine sinus can also be visualized.

Nuclear Medicine Tests

• No role in the evaluation of VOGMs

Electrodiagnostic Tests

• EEG: EEG may be used to monitor seizure activity, particularly subclinical seizures.
• ECG: ECG may be utilized as part of a cardiac evaluation, although echocardiogram is preferred and crucial to investigate cardiac function and structural defects.

Neuropsychological Tests

• Detection of developmental delay: Developmental delay in older infants or children may be detected through history taking (including parent interview) and tools such as the Denver Developmental Screening Test (52).
• Comprehensive neurocognitive assessment: This can be performed to detect subclinical neurocognitive decline as part of long-term follow-up for patients treated with embolization (70-72).

Correlation of Tests

• Severity and urgency: Physical exam findings and results of laboratory tests may indicate the severity of the lesion and suggest the urgency of intervention.
• Evaluation via imaging: Prenatal and postnatal ultrasound, chest x-ray, MRI, and MR angiography may play a role in the detection, diagnosis, and initial evaluation of VOGM. Cerebral angiography is the gold standard of evaluation and is necessary prior to any endovascular embolization procedure, as the dynamic and selective nature of angiography delineates arterial feeders and the associated hemodynamic phenomena.