Functional angiography of the head and neck.

The basic concepts of the territorial approach to angiography and intravascular embolization of vascular lesions of the head and neck are reviewed. Superselective arteriographic injections are performed in sequences and projections tailored to the suspected location of the vascular lesion. The resulting studies are then reviewed as a whole, so that a complete angiographic map of the tissue territory involved is considered. From this map the interventionalist selects the best and safest route for embolization, taking into account developmental and acquired constraints to blood flow and the presence of any potentially dangerous collateral flow toward normal nervous tissue. Case studies are presented to illustrate the most frequently encountered anatomic variants that may, by their presence within the circulation to be embolized, increase the risk of complication. Attention is directed toward the probability of intraprocedural changes in hemodynamic balance and flow direction, which also may increase risk and which may be modified by catheter techniques and minimized by meticulous attention to detail. This article should support the contention that functional angiography and careful attention to the resulting angiographic map are essential for efficacious and safe head and neck embolization.