Both Dyna CT, a rotational faultage reconstructed technique, and digital subtraction angiography (DSA) play important roles in the diagnosis and treatment of arteriovenous malformations (AVM). Three-dimensional Dyna CT can provide the spatial information of AVM nidus, while two-dimensional DSA can provide the time information for distinguishing arteries and veins. To illustrate the location relationship of the nidus, arteries and veins at the same time, these two imaging modalities need to be fused. In this paper, a two-dimensional to three-dimensional back projection and growing method is proposed, which realizes the image fusion of two-dimensional DSA and three-dimensional Dyna CT and achieves the differentiation of arteries and veins in Dyna CT. The experimental results showed that the fusion image could present both the position information of AVM nidus and the dynamic information of the blood vessels. Therefore, the proposed method can help surgeons locate the AVM abnormality and make operation plan more accurately.