Interventional 2D/3D Registration with Contextual Pose Update

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Date
2019-05-06
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Publisher
Johns Hopkins University
Abstract
Traditional intensity-based 2D/3D registration requires near-perfect initialization in order for image similarity metrics to yield meaningful gradient updates of X-ray pose. They depend on image appearance rather than content, and therefore, fail in revealing large pose offsets that substantially alter the appearance of the same structure. We complement traditional similarity metrics with a convolutional neural network-based (CNN-based) similarity function that captures large-range pose relations by extracting both local and contextual information, and proposes meaningful X-ray pose updates without the need for accurate initialization. Our CNN accepts a target X-ray image and a digitally reconstructed radiograph at the current pose estimate as input and iteratively outputs pose updates on the Riemannian Manifold. It integrates seamlessly with conventional image-based registration frameworks. Long-range relations are captured primarily by our CNN-based method while short-range offsets can be recovered accurately with an image similarity-based method. On both synthetic and real X-ray images of the pelvis, we demonstrate that the proposed method can successfully recover large rotational and translational offsets, irrespective of initialization.
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Keywords
Image-guided surgery, machine learning, X-ray, CT, Riemannian Manifold
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