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Ischemic stroke has great correlation with carotid atherosclerosis and is mostly caused by vulnerable plaques. It’s
particularly important to analysis the components of plaques for the detection of vulnerable plaques. Recently plaque
analysis based on multi-contrast magnetic resonance imaging has attracted great attention. Though multi-contrast MR
imaging has potentials in enhanced demonstration of carotid wall, its performance is hampered by the misalignment of
different imaging sequences. In this study, a coarse-to-fine registration strategy based on cross-sectional images and wall
boundaries is proposed to solve the problem. It includes two steps: a rigid step using the iterative closest points to register
the centerlines of carotid artery extracted from multi-contrast MR images, and a non-rigid step using the thin plate spline
to register the lumen boundaries of carotid artery. In the rigid step, the centerline was extracted by tracking the crosssectional
images along the vessel direction calculated by Hessian matrix. In the non-rigid step, a shape context descriptor
is introduced to find corresponding points of two similar boundaries. In addition, the deterministic annealing technique is
used to find a globally optimized solution. The proposed strategy was evaluated by newly developed three-dimensional,
fast and high resolution multi-contrast black blood MR imaging. Quantitative validation indicated that after registration,
the overlap of two boundaries from different sequences is 95%, and their mean surface distance is 0.12 mm. In conclusion,
the proposed algorithm has improved the accuracy of registration effectively for further component analysis of carotid
plaques.
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