What's the next step for a child with progressive facial asymmetry and a normal non-contrast Magnetic Resonance Imaging (MRI)?

Next Step: Contrast-Enhanced MRI

In a four-year-old with progressive facial asymmetry and a normal non-contrast MRI, the next step is to perform MRI with intravenous contrast to evaluate for vascular malformations, infantile hemangiomas, or other soft tissue anomalies that may not be visible without contrast enhancement. 1

Why Contrast is Critical

• Vascular malformations require contrast for proper characterization. Non-contrast MRI cannot adequately differentiate between low-flow and high-flow vascular malformations, nor can it assess the full extent of soft tissue involvement that commonly causes progressive facial asymmetry 1

• Contrast-enhanced MRI shows intense enhancement of involved soft tissues, cyst walls, and vascular structures that are invisible on non-contrast sequences, with sensitivity of 83% and specificity of 95% for differentiating vascular malformation types 1

• Progressive asymmetry in a young child strongly suggests an active pathologic process rather than static congenital anomaly, making contrast evaluation essential to identify treatable causes 1, 2

Specific Imaging Protocol

• Order MRI face/orbits/neck without and with IV contrast using thin-section sequences focused on the affected facial region 1

• Include time-resolved contrast-enhanced sequences (dynamic MRA) to assess blood flow dynamics and distinguish high-flow from low-flow lesions, which directly impacts treatment planning 1, 3

• Ensure dedicated soft tissue sequences with fat suppression to evaluate deep facial structures and periorbital regions where vascular anomalies commonly extend 1

Key Diagnostic Considerations

Vascular Malformations

• Low-flow venous malformations are the most common cause of progressive facial asymmetry in children and show characteristic intense enhancement on contrast MRI 1

• Arteriovenous malformations require identification of feeding arteries and draining veins visible only with contrast-enhanced dynamic sequences 1, 3

Infantile Hemangiomas and Associated Syndromes

• Large segmental facial hemangiomas (>5 cm) warrant evaluation for PHACE syndrome, requiring MRI/MRA of head and neck including aortic arch 1

• Contrast administration is essential for detecting active hemangioma tissue and differentiating from involuting lesions, as enhancement patterns change with treatment response 1

Infiltrating Lipomatosis

• Congenital infiltrating lipomatosis causes progressive facial asymmetry with accelerated dental development on the affected side, requiring contrast to delineate soft tissue extent 2

Critical Pitfalls to Avoid

• Do not assume a normal non-contrast MRI excludes significant pathology in progressive facial asymmetry—many vascular and soft tissue lesions are only visible with contrast 1, 4

• Do not delay contrast imaging while pursuing other workup, as progressive asymmetry in a 4-year-old requires urgent characterization to guide treatment and prevent complications 1, 2

• Do not order CT as an alternative—MRI with contrast provides superior soft tissue characterization without ionizing radiation, which is particularly important in young children 1

Additional Workup Based on Contrast MRI Results

If High-Flow Vascular Malformation Identified

• Obtain echocardiography to assess for cardiac anomalies associated with PHACE syndrome 1

• Consider conventional angiography for treatment planning if embolization or sclerotherapy is contemplated 1

If Low-Flow Venous Malformation Identified

• Doppler ultrasound can supplement MRI for follow-up monitoring and assessing treatment response 1

• Radiography may identify phleboliths (calcified thrombi) characteristic of venous malformations 1

If Contrast MRI Remains Normal

• Reassess for non-vascular causes including hemifacial microsomia, condylar hyperplasia, or subtle skeletal asymmetry requiring dedicated facial CT 1

• Consider genetic evaluation for syndromic causes of facial asymmetry if dysmorphic features present 1

Sedation Considerations

• Most 4-year-olds require sedation or general anesthesia for contrast-enhanced MRI to ensure adequate image quality 1

• Coordinate with anesthesia team to optimize imaging protocol and minimize sedation time while obtaining necessary sequences 1

• Infants under 3 months may sleep through MRI if fed immediately before and swaddled, but a 4-year-old will require formal sedation 1