Biomedical subjects

Peter Heinze

Publications and source records attributed to Peter Heinze.

4 recordsLinked to original sources

PubMed2002

Atlas-based segmentation of pathological knee joints.

Efficiency, comparability and simplicity are key aspects for user acceptance of surgical planning systems in the long term. Automatic segmentation and identification of geometric reference systems of the anatomical structures are essential to fulfill these requirements. A statistical motivated shape atlas of the knee joint, based on 235 normal and abnormal MR and CT volume sets, is constructed for automatic segmentation of CT image data. In the first step of the atlas construction, the bony structures of the knee were segmented semi-automatically and processed into a dense and a sparse triangulated surface mesh to obtain training data sets. To establish an inter-individual correspondence, a skeleton-based registration method is used. The registered sparse surface meshes are retriangulated to estimate a pointwise inter-individual correspondence. The shape atlas is build upon these correspondences and integrated into a segmentation algorithm. An iterative segmentation scheme is proposed, which consists of a combination of the iterative-closest-point algorithm for spatial registration and of a downhill-simplex optimization procedure for deformation of the statistical motivated shape atlas to the image data. We expect the statistical shape model to be a robust and image modality independent method for the segmentation of pathological knee joints in CT image data.

Arthroplasty, Replacement, Knee↗

PubMed2002

Realtime textured 3D-models for medical applications.

Realistic visualisation becomes more and more important in medicine. Whenever a patient individual 3D-model was generated the aim is to visualise the model as realistic as possible. We use 3D-models in our diagnostic and therapeutic tools for intraoperative visualisation of e.g. CT-scans. Most medical tools uses surface-rendering or volume-rendering for virtual visualisation. The coloration of a visualised model is normally done by using a convenient colour for each surface resp. volume. Our approach for 3D-models generated from motion in image series (e.g. videoendoscopes) is to add textures to the 3D-model. The main problem is, to handle the huge amount of videoimage-data (20Mb/sec.) and render the model in realtime.

Computer Simulation↗

PubMed2002

3D structure from endoscopic images.

Endoscopy is an important procedure for the diagnostic and therapy of various pathologies. In 2000, the Institute for Process Control and Robotics/Universität Karlsruhe (TH) has developed a basic framework for reconstructing 3D models from image sequences. The framework is able to realise automatic navigation for new colonoscopes with own driving system and on the other hand to offer a virtual 3D endoscopic view during bad visibility conditions caused by e.g. abrupt bleeding. This method generates a 3D-model intraoperatively compared to preoperatively generated 3D-models in virtual endoscopy.

Colonography, Computed Tomographic↗

PubMed2002

CT, MRI and video based analysis of knee kinematics--a basis for CT based simulation.

With the new computer aided surgery techniques a surgery can be split in two phases, which are pre-operative planning and intervention. The planning is frequently based on three dimensional image data and takes place in the office of the surgeon. Using this approach the surgical feeling, the physical feedback of the patient, is not available during the planning phase. However, this feedback yields information, which is helpful or necessary for the planning. This lack of information can be compensated by a simulation module, which simulates kinematic data from image volume data. To develop such a module first both image volume data and kinematic data have to be captured from a wide range of patients. In this work a new approach for kinematic analysis of the knee is presented which yields an accuracy which is necessary for such simulation. Because the analysis has to be done for many patients the degree of invasiveness is emphasized. This contactless and non invasive approach is based on external fixations, anatomical skin markers, video sequences and computer tomograms. Position tracking of femur and tibia for any motion pattern is possible. Because the individual anatomic structures extracted from the tomogram are tracked, an analysis of any point or coordinate system can be done later using the originally captured data. This gives a new degree of freedom for analysis.

Biomechanical Phenomena↗