Event Location: NSH 1305
Bio: Septimiu (Tim) E. Salcudean (S’78-M’-79-SM’03-F’05) received the B. Eng (Hons.) and M.Eng degrees from McGill University and the Ph.D. degree from U.C. Berkeley, all in Electrical Engineering. From 1986 to 1989, he was a Research Staff Member in the robotics group at the IBM T.J. Watson Research Center. He then joined the Department of Electrical and Computer Engineering at the University of British Columbia, Vancouver, Canada, where he is now a Professor and holds a Canada Research Chair and the C.A. Laszlo Chair in Biomedical Engineering. He spent one year at ONERA-CERT (aerospace controls laboratory) in Toulouse, France, in 1996-1997, where he held a Killam Research Fellowship, and six months, during 2005, in the medical robotics group (GMCAO) at CNRS in Grenoble. France. His current research interests are in medical robotics and ultrasound image guidance, elastography, medical simulation and virtual environments. Prof. Salcudean has been a co-organizer of several symposia on haptic interfaces and has served as a Technical and Senior Editor of the IEEE Transactions on Robotics and Automation. He is a Fellow of the Canadian Academy of Engineering and of the IEEE.

Abstract: Elastography imaging is concerned with the measurement and display of tissue strain or with the identification of tissue intrinsic properties from the measured strain in response to an external or internal mechanical excitation. Current elastography techniques enable not only generic, but patient-specific deformable models to be acquired. Elastography as an imaging modality presents us with a rich and beautiful set of inter-disciplinary problems, and includes tissue actuator design, specific image sequence design, motion estimation from images, viscoelastic parameter estimation from motion, and computational acceleration of these to the level where real-time performance is achieved. We will first present a tutorial introduction to elastography, focussing primarily on ultrasound elastography. We will then present some of our own contributions to elastography, including wave imaging and elasticity reconstruction techniques. As a clinical application, we will show that, in particular, elastography images are better at delineating the prostate than B-mode ultrasound.

We will also present our use of elastography to derive coarse finite element models of the anatomy. Conventional schemes for generating meshes consist of a segmentation step delineating the anatomy, followed by a meshing step that generates elements conforming to this segmentation. We have developed an energy-based finite element model generation technique that facilitates segmentation by adjusting mesh nodes to minimize a global measure of the strain/elasticity variance within the mesh elements. This tends to align the elements to the underlying anatomical image, and produces coarse meshes that accurately represent anatomy.

We will demonstrate the use of deformable models in a prostate brachytherapy simulator, which combines a number of novel features, including the realistic display of ultrasound images conforming to the deforming mesh and the image-based realistic rendering of needles and brachytherapy seeds.

Progress on current projects aimed at providing ultrasound and elastography capability to the da Vinci surgical system will be briefly reviewed.