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All image-guided neurosurgical systems that we are aware of assume that the head and its contents behave as a rigid body. It is important to measure intraoperative brain deformation (brain shift) to provide some indication of the application accuracy of image-guided surgical systems, and also to provide data to develop and validate nonrigid registration(More)
Creases are a type of ridge/valley structures of an image characterized by local conditions. As creases tend to be at the center of anisotropic grey-level shapes, creaseness can be considered a measure of medialness, and therefore as useful in many image analysis problems. Among the several possibilities, a priori the creaseness based on the level-set(More)
Ridges and valleys are earth's relief structures. They can have an imaging counterpart provided we model a digital image as a landscape by considering grey level values as height. These two dual entities have received comparatively little attention from the computer vision community with regard to others like edges or corners. In this paper we first propose(More)
sion tomography using 14F-deoxyglucose and single photon emission computed tomography using 131IMP showed reduced cerebral blood flow in the left frontal region, particularly in the perisylvian area. Several pathological conditions have been described as an underlying cause of PPA, such as Pick's disease, Alzheimer 's disease, CreutzfeldtJakob disease, or(More)
This paper addresses the registration of ultrasound scans and magnetic resonance (MR) volume datasets of the same patient. During a neurosurgery intervention, pre–operative MR images are often employed as a guide despite the fact that they do not show the actual state of the brain, which sometimes has sunk up to 1 cm. By means of a standard ecographer and a(More)
Ultrasound imaging is a helpful aid for diagnosis in many medical specialities. In order to enhance the information available to the examiner, an upcoming approach is to compound the sequence of video images into a single 3D volume, which needs a real-time tracking of the transducer. However, errors in the positioning occur, and the compounded image becomes(More)