Phase-Based Nonrigid Deformation for Digital Subtraction Angiography

We present a method for digital subtraction angiography based on phase-based nonrigid deformation with specific consideration for changes between the image pairs. Input images are transformed into a scale-space representation using complex-valued filter responses. We apply a novel selection criterion to discern object motion and actual change by comparing the magnitudes in the responses. By manipulating phase, we directly generate a deformed image without explicit calculation of motion vectors. Our method is particularly useful in angiographic imaging where subtle changes between the image pairs should be preserved within the deformation and subtraction process. The experiments show that the proposed method preserves contrast for vessels and tumor stains while reducing motion artifact, which is clinically meaningful.