A 14-year-old boy with a known nasopharyngeal angiofibroma is being evaluated for surgical planning. His MRI shows extension into the sphenoid sinus and possible involvement of the cavernous sinus. Which additional investigation is most appropriate to assess vascular anatomy and plan preoperative embolization?

## Preoperative Vascular Assessment in Nasopharyngeal Angiofibroma ### Role of Digital Subtraction Angiography in NAF Management **Key Point:** Digital subtraction angiography (DSA) with selective catheterization is the gold standard for preoperative assessment of vascular supply and planning of embolization in nasopharyngeal angiofibroma. **High-Yield:** DSA provides: - Identification of feeding arteries (maxillary, ascending pharyngeal, internal carotid) - Assessment of collateral circulation - Determination of embolization feasibility and strategy - Real-time visualization of vascular anatomy during intervention - Ability to perform therapeutic embolization in the same session ### Diagnostic vs. Therapeutic Role | Investigation | Diagnostic Role | Therapeutic Role | Timing | |---|---|---|---| | MRI with gadolinium | Gold standard for diagnosis and extent | None | Initial assessment | | DSA with catheterization | Detailed vascular anatomy | Preoperative embolization | Immediately before surgery | | CT angiography | Supplementary vascular assessment | None | Not standard | | Doppler ultrasound | Limited vascular assessment | None | Not useful for NAF | **Clinical Pearl:** Preoperative embolization reduces intraoperative blood loss by 50–80% and is now considered standard of care in most centers managing NAF. DSA is essential for planning this intervention. ### Characteristic Vascular Findings in NAF 1. **Primary feeders:** Maxillary artery (most common), ascending pharyngeal artery 2. **Secondary feeders:** Branches of internal carotid artery, facial artery 3. **Venous drainage:** Usually via pterygoid venous plexus and internal jugular vein 4. **Tumor blush:** Intense, persistent capillary phase enhancement **Warning:** Cavernous sinus involvement requires careful assessment of internal carotid artery relationship — DSA clarifies this critical anatomical relationship before surgery. ### Why Other Options Are Inadequate **MR Angiography:** While non-invasive, lacks the temporal resolution and selective catheterization capability needed for detailed vascular mapping and embolization planning. **CT Angiography:** Provides vascular information but inferior to DSA for selective assessment of individual feeding vessels and does not allow therapeutic intervention. **Doppler Ultrasound:** Operator-dependent, limited field of view, and inadequate for comprehensive vascular assessment in complex cases with cavernous sinus involvement.