Real-time digital subtraction angiography for therapeutic neuroradiologic procedures.

Procedural control during therapeutic neuroradiologic procedures is generally based on repeated angiograms to assess the degree to which embolization has reduced abnormal blood flow. Due to the complex craniofacial skeletal anatomy that is superimposed over lesions in this area, subtraction studies are usually required to see the vessels and visualize a tumor stain satisfactorily. We have used a device incorporating continuous recursive digital video filtration, which allows the operator to view a subtracted fluoroscopic image of each control angiographic sequence in real time. The advantages of this technique for therapeutic procedures are described.