First ERCIM Workshop on Informatics and Mathematics Applied to Interventional Medicine
by Marc Thiriet
The first workshop of the IM2IM ERCIM Working Group was held from 1-2 December 2003 at CRP Henri Tudor in Luxembourg, as part of the ERCIM biannual meetings hosted by the Luxembourg National Research Fund (FNR).
Participants attended from Canada, Chile, France, Germany, Greece, Italy, Spain, Switzerland and the UK. The set of presentations covered the necessary topics involved in the development of medical simulators.
Medical image processing and virtual reality was discussed by L. Soler, who pointed out the usefulness of navigation tools and medical robotics to our community, a fact which had not hitherto been widely appreciated.
Three-dimensional reconstructions of anatomical organs are a popular research theme (talks from N. Gabrielides, National Technical University of Athens, D. Manoussaki working at FORTH, J. Peiro, Imperial College London and M. Thiriet for the INRIA teams EPIDAURE and REO). Medically oriented flow computations must be performed in image-based discretised domains due to the huge between-subject variability in vessel anatomy and to the patient-dependent shape of the vessel-wall pathologies. Once the three-dimensional reconstruction is made, the mesh must be compatible with the constraints of scientific computing (presentation of L. Baffico, Universidad de Chile and M. Thiriet). Furthermore, mesh adaptation and adaptivity are necessary in the case of unsteady phenomena such as cryotherapy for liver tumours (talk from Youssef Belhamadia, GIREF, Université Laval, Quebec, Canada).
Biofluid flow modelling must also take into account the deformation of the vessel wall during pressure-wave propagation or environment loading, in particular changes in external pressure during respiration, and especially in thoracic vessels. The rheology of the moving fluid and of the bio-conduit wall must be determined in vivo. At the same time, suitable software must take into account the complete set of rheological properties of the composite bio-tissues, with possible structure changes (presentation of A. Pascau, University of Zaragoza, Spain on Non-Newtonian fluids and M. Thiriet). Due to the geometry of the vessels and the mechanics of the wall and flow genesis, the bioflow models being developed are three-dimensional, generally laminar and quasi-periodic (talk from Giuseppe Pontrelli, CNR, Roma and M. Thiriet). Moreover, although it belongs to a network with the cardiac pump and its input and output impedances, the three-dimensional region of interest is rather limited. Multiphysics multiscale modelling is also being investigated (presentation of M. Fernandez, Ecole Polytechnique Fédérale de Lausanne and J. Peiro). Lumped parameter models may be used for various regions of the vessel network.
New procedures are also being developed however, including the reduced basis element method with fractal and multiphysics homogenisation (talk from Y. Maday, Université Pierre et Marie Curie, Paris). Such complete modelling is associated with a large computational cost. Fast solvers are therefore necessary, using geometric and algebraic multigrid and domain decomposition techniques, and coupling of sequential and parallel codes (presentation of W. Joppich, Fraunhofer-Institute for Algorithms and Scientific Computing (SCAI), Germany).
Mass transport by the fluid conveyed in bio-conduits is investigated in order to understand vessel-wall lesions and to develop new local or bulk therapy strategy. Aerosol transport and deposition in the airways still needs to be accurately modelled in the physical sense (talk from P.-E. Jabin, Ecole Normale Supérieure, Paris). Mini-invasive medical procedures use the body's natural paths, the vessels. Interventional medicine treats vessel-wall damages with medical devices, which are displaced through the vascular bed and deployed within the lesion using catheter-based techniques. The design and shape optimisation of such devices, as well as ventricule-assist pumps is currently of major interest (presentation of M.-I. Farinas, Ecole Polytechnique de Montréal, Canada).
During the final session it was decided that the next IM2IM workshop would be held in Marseille in August 2004, in order to coincide with a six-week summer school in biomathematics. It is planned to hold the following workshop at IRCAD in Strasbourg in December 2005. The Working Group intends to submit a proposal under the European Commission's Future and Emerging Technologies scheme to drive the Working Group in a precise direction.
Marc Thiriet, INRIA