Automatic Registration of Cerebral Vascular Structures

In this paper we present a registration method for cerebral vascular structures in the 2D MRA images. The method is based on bifurcation structures. The usual registration methods, based on point matching, largely depend on the branching angels of each bifurcation point. This may cause multiple feature correspondence due to similar branching angels. Hence, bifurcation structures offer better registration. Each bifurcation structure is composed of a master bifurcation point and its three connected neighbors. The characteristic vector of each bifurcation structure consists of the normalized branching angle and length, and it is invariant against translation, rotation, scaling, and even modest distortion. The validation of the registration accuracy is particularly important. Virtual and physical images may provide the gold standard for validation. Also, image databases may in the future provide a source for the objective comparison of different vascular registration methods.