Role of image fusion combining three-dimensional digital subtraction angiography with magnetic resonance imaging in evaluation of unruptured cerebral aneurysms.

Objectives: The goal of this study was to evaluate the usefulness of a recently developed image fusion of three-dimensional digital subtraction angiography (3D DSA) and magnetic resonance (MR) images, DSA-MR fusion, in the pre-treatment assessment of cerebral aneurysm. Methods: Eighteen patients with 21 unruptured anterior or posterior circulation aneurysms underwent pre-treatment DSA-MR fusion. The authors independently assessed whether DSA-MR fusion images provided any useful additional information compared with analysing 3D DSA and MR images separately, and if this had an impact on the therapeutic decision-making of unruptured aneurysms. Results: DSA-MR fusion images were obtained within 30 minutes for all patients. In 19 of 21 aneurysms, it provided the following additional information to the findings of 3D DSA, MR images or both: the passing course in the brain tissues of perforating arteries near or originating from an aneurysm, and/or the spatial relationship between an aneurysm and an oculomotor nerve. This information from DSA-MR fusion images was useful for diagnosis, therapeutic decision-making and the risk assessment associated with the treatment, as well as patient education regarding cerebral aneurysm. Discussion: DSA-MR fusion images were useful for the pre-treatment evaluation of unruptured cerebral aneurysms as a supplement to DSA and MR images.