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New Procedure to Make Brain Surgery Safer

To increase patient safety in clinical practice and minimize risks and damage that may arise during surgery, computer support and digital medical imaging are key technologies. Before brain operations, neurosurgeons can now evaluate patient-specific surgical risks, achieve increased safety, and avoid unacceptable risks.

Brain interventions must be planned so that the neurosurgeon can access and remove the tumor without causing unnecessary damage. Before the brain tumor can be removed, crucial questions must be answered. Where do the functional areas of the cortex (gray matter) of the patient lie? What are the paths of the nerve fiber tracts that connect them? Answering these questions is important because the functional areas of the brain are interconnected via nerve pathways, also known as nerve fiber tracts. These nerve tracts must be protected as much as possible; otherwise, permanent dysfunction could occur. Furthermore, nerve tracts can be pushed or infiltrated by the brain tumor itself. If nerve tracts become damaged during an operation, there is a risk that distant functional areas connected to the tumor-afflicted part of the brain could be affected and induce lasting sensory, motor, and cognitive impairment. Therefore, neurosurgeons attempt to answer these questions for each patient during the planning stage of the brain operation to minimize the risks present in the intervention. To do so, surgeons require medical imagery of each patient's brain anatomy and function that is as realistic and precise as possible. However, medical images contain inaccuracies that arise from the processing, modeling, and reconstruction of patient data.

Solving these problems requires more than merely improving existing imaging methods. Mathematical analysis and models must be integrated to produce information about the location of the tumor, functional areas, and nerve fiber tracts, to increase the accuracy of patient-specific data, and to give the surgeon dependable knowledge.

The Fraunhofer MEVIS Institute for Medical Image Computing in Bremen, Germany has pioneered a procedure that analyzes uncertainty in patient-specific images, modeling, and reconstruction and incorporates this information into reconstructions of patient data. This procedure allows safety margins around nerve tracts in the brain to be more accurately determined. In addition, the reliability of the reconstructed data is calculated to supply the surgeon with accurate information concerning nerve tract locations, paths, and intersections and to construct safety margins around the nerve fiber tracts. By integrating errors in measurement, reconstruction, and modeling, the exact locations of tracts in a space-occupying tumor are calculated. This gives the neurosurgeon a reliable prognosis concerning where the incision in the brain should be made and which safety margins should be chosen to avoid harming nerve tracts and irreversibly damaging important functional areas. Before an intervention, the surgeon can evaluate patient-specific risks. These software assistants will be refined and implemented for neuronavigation in future operations, providing the surgeon with updated information during surgery that can be compared to planning data.

The paths of nerve tracts in the brain and the functional areas that they connect can now be explored by visitors of the "New Paths in Medicine" exhibit on the MS Wissenschaft exhibition ship. The converted inland vessel is underway until September 29, 2011 and docks in 35 different cities. During the "Year of Health Research", visitors can familiarize themselves with the field's newest trends, developments, and research findings. The exhibit showcases a physical three-dimensional model of the brain produced through an innovative printing process based on the medical image data of a real person. This brain model can be touched and viewed from different angles thanks to its rotating base. Nerve tracts can be activated by touching sensors on the physical model that correspond to functional areas of the brain. The brain is displayed on a screen along with the activated nerve tracts that are responsible, for instance, for sight, speech, feeling, and motion. This new form of interactive exhibit was developed by Fraunhofer MEVIS in Bremen together with the Universum® Science Center in Bremen to demonstrate how modern image processing combined with mathematics and intelligent software can help make neurosurgical operations more predictable and safe. The three-dimensional print of the brain was produced by the Fraunhofer-Institut ITWM in Kaiserslautern.

Background Information: Since 1995, Fraunhofer MEVIS has pioneered research and development of computer assistance for image-based, personalized medicine. Risk minimization in planning and surgical intervention constitutes an important field of activity. Researchers at Fraunhofer MEVIS develop mathematical models that characterize the human body's structures such as the vascular tree of the liver or the bronchi of the lung. These models are processed for each patient and used to determine how much of a tumor and surrounding tissue can be removed and when to mind safety margins to protect vital structures. Thanks to detailed, patient-specific reconstructed models of organs, surgeons can estimate the risks of an operation before intervention and plan optimal procedures. With more than 100 clinical partners worldwide and over 5,500 prepared clinical cases for liver surgery planning alone, Fraunhofer MEVIS draws upon extensive experience in surgical operation planning and clinical procedures. This experience has led to the development of a navigation system for liver surgery which records ultrasound data and correlates it with planning data. During surgery, new information can be recorded and added to the planning data.

With the help of the dependable knowledge gained from reconstruction and analysis, surgeons no longer need to rely solely on implied knowledge attained through experience. Skilled and experienced surgeons can reliably conduct an intervention and identify risks without having to explicitly specify why they have intuitively chosen to abandon a conventional surgical path in favor of a different one. Less-experienced surgeons lack this implicit knowledge. Fraunhofer MEVIS software assistants can also help these surgeons work more safely by providing this knowledge. This is relevant not only for individual patients, but also for the quality of care as a whole. Thanks to these new processes and software assistants developed by Fraunhofer MEVIS, the quality of care in both urban and rural clinics can be improved.

Contact: Dr. Guido Prause Phone +49 421 218-59004 guido.prause@mevis.fraunhofer.de

About Fraunhofer MEVIS: The Fraunhofer Institute for Medical Image Computing MEVIS in Bremen is one of the world's leading internationally connected research and development centers for computer assistance in image-based medicine. It follows a patient-centered, workflow-oriented approach towards resolving clinically relevant issues in image-based diagnosis and therapy. Fraunhofer MEVIS concentrates on epidemiologically significant diseases of the cardiovascular system, brain, liver, and lung, as well as oncological disorders.

idw :: 31.05.2011