4D DSA a new technique for arteriovenous malformation evaluation: a feasibility study

Background The angioarchitectural features of an arteriovenous malformation (AVM) provide key information regarding natural history and treatment planning. Because of rapid filling and vascular overlap, two-dimensional (2D) and three-dimensional (3D) digital subtraction angiography (DSA) are often suboptimal for evaluation of these features. We have developed an algorithm that derives a series of fully time-resolved 3D DSA volumes (four-dimensional (4D) DSA) at up to 30 frames/s from a conventional 3D DSA. The temporal/spatial resolution of 4D reconstructions is significantly higher than that provided by current MR angiography and CT angiography techniques. 4D reconstruction allows viewing of an AVM from any angle at any time during its opacification. This feasibility study investigated the potential of 4D DSA to improve the ability to analyze angioarchitectural features compared with conventional 2D and 3D DSA. Methods 2D, 3D, and 4D DSA reconstructions of angiographic studies of six AVMs were evaluated by three cerebrovascular neurosurgeons and one interventional neuroradiologist. These observers evaluated the ability of each modality to visualize the angioarchitectural features of the AVMs. They also compared the information provided using the combination of 2D and 3D DSA with that provided by a 4D DSA reconstruction. Results By consensus, 4D DSA provided the best ability to visualize the internal features of the AVM including intranidal aneurysms, fistulae, venous obstructions, and sequence of filling and draining. 2D and 3D images in comparison were limited because of overlap of the vasculature. Conclusions In this small series, 4D DSA provided better ability to visualize the angioarchitecture of an AVM than conventional methods. Further experience is required to determine the ultimate utility of this technique.