Vessel extraction in medical images by wave-propagation and traceback

Presents an approach for the extraction of vasculature from angiography images by using a wave propagation and traceback mechanism. The authors discuss both the theory and the implementation of the approach. Using a dual-sigmoidal filter, they label each pixel in an angiogram with the likelihood that it is within a vessel. Representing the reciprocal of this likelihood image as an array of refractive indexes, the authors propagate a digital wave through the image from the base of the vascular tree. This wave "washes" over the vasculature, ignoring local noise perturbations. The extraction of the vasculature becomes that of tracing the wave along the local normals to the waveform. While the approach is inherently single instruction stream multiple data stream (SIMD), the authors present an efficient sequential algorithm for the wave propagation and discuss the traceback algorithm. They demonstrate the effectiveness of their integer image neighborhood-based algorithm and its robustness to image noise.