A virtual liver, a better chance of life

Scientists have developed systems to construct 3D images of individual patients' livers, with their tumours or other pathologies, from MRI or CT-scans. The reconstructions can be transmitted to external experts in any location, for consultation in real time just before surgery. Collaborative decisions can be made and optimal therapy planned with the best possible diagnostic support, before real surgery is attempted. Simulation of laparoscopic and robotic surgery, with tissue resistance, can be used either to practise the exact surgery proposed for an individual patient, or also for training several surgeons simultaneously.

Medical imaging of organs and tissues has contributed greatly to diagnosis and therapy planning, especially in the treatment of cancers, which are the major cause of deaths worldwide. However the 2D scanning images possible until now have been difficult to interpret, and it has not been possible to consult others who are not present in person. The EUREKA project Odysseus has developed software for 3D-imaging of the blood vessels of a patient's liver which has materially advanced medical understanding of how the liver is segmented. Until now, liver surgery has been based on the anatomy classically described by Couinaud in 1957. But the 3D modelling has shown that up to 50% of patients have a significantly different liver structure from the Couinaud description. "Thanks to the 3D modelling," says Professor Luc Soler of the Institut de Recherche pour les Cancers de l'Appareil Digestif (IRCAD), "the future of liver surgery has gained more precision through accurate definition of the liver's blood vessels."

Virtual Patient Modelling (VR-Anat, formerly known as 3D-VPM) uses patient-specific data to enable pre-operative assessment. Diagnosis and Virtual Planning (VR Planning, formerly 3D DVP) is software which enables navigation and tool positioning within 3D images that can be reconstructed from any multimedia-equipped computer. These two sets of software were developed by IRCAD in collaboration with the French Institut National de Recherche en Informatique et Automatique (INRIA), and tested in five hospitals in France, Switzerland and Canada.

France Telecom, also a partner in the Odysseus project, developed the communication system called Argonaute, allowing several practitioners in different places to interact and advise on the images simultaneously. The unlimited laparoscopic simulator (ULIS) and the robotic surgery simulator (SEP Robot) added realistic physical properties of texture and tissue resistance to the 3D model of the patient, allowing surgical intervention to be simulated before real surgery. These simulations were developed respectively by the German endoscope manufacturer Karl Storz and by SimSurgery of Norway. Luc Soler holds that it is now difficult to tell the difference between photos of real surgery and the simulator images.

Better prospects for patients

The products of Odysseus will make a very significant contribution to the accuracy of tumour diagnosis in the liver and its treatment. Once trials and validation are complete, their use will enable more accurate diagnosis of secondary liver tumours so they can be removed completely; and reduce the size of liver segments that need to be resected. Because the success of liver surgery depends on the minimum volume of liver that can safely remain after surgery, accurate knowledge of the topology of the individual liver should significantly increase the number of patients who are eligible for surgery.