Proceedings of Spie the International Society For Optical Engineering, Feb 9, 2006
For planning, simulation and documentation of interventions in maxillofacial surgery high resolvi... more For planning, simulation and documentation of interventions in maxillofacial surgery high resolving soft tissue information of the human face in upright position is needed. This information can be gained by holographic methods, which allow a recording of the whole face in an extremely short time period, so that no movement artefacts occur. The hologram is recorded with a single laser pulse of 25 ns duration and stored in photosensitive material. After automated wet-chemical processing, the hologram is optically reconstructed with a cw-laser. During the optical reconstruction, a light field, which is a one-to-one three-dimensional representation of the recorded face, emerges at its original position and is digitized into a set of two-dimensional projections. Digital image processing leads to merging of these projections into a three-dimensional computer model. Besides the topometric information, a high resolving pixel precise texture is also extracted from the holographic reconstruction and used for the texturing of the computer models. The use of mirrors allows the simultaneous recording of three different views of the face with one laser pulse. The three different views of the face can be combined easily, because they are simultaneously recorded. Thus a recording range of approximately 270 degrees is achieved. In addition to the medical application, high resolving and textured computer models of faces are of tremendous importance for facial reconstruction in anthropology, forensic science and archaeology.
ABSTRACT Anatomy related heterogeneous discontinuities in material properties strongly influence h... more ABSTRACT Anatomy related heterogeneous discontinuities in material properties strongly influence human soft tissue behavior under mechanical load. We present a parametric model of the aortic root, which defines multi-material surface regions for advanced tissue property control and supports patient-specific model refinement. Our results strongly indicate improvements for in-silico clinical application experiments using multi-material simulation.
This paper describes a new approach for the reconstruction of complete 3-D arterial trees from pa... more This paper describes a new approach for the reconstruction of complete 3-D arterial trees from partially incomplete image data. We utilize a physiologically motivated simulation framework to iteratively generate artificial, yet physiologically meaningful, vasculatures for the correction of vascular connectivity. The generative approach is guided by a simplified angiogenesis model, while at the same time topological and morphological evidence extracted from the image data is considered to form functionally adequate tree models. We evaluate the effectiveness of our method on four synthetic datasets using different metrics to assess topological and functional differences. Our experiments show that the proposed generative approach is superior to state-of-the-art approaches that only consider topology for vessel reconstruction and performs consistently well across different problem sizes and topologies.
Forensic Science Medicine and Pathology, Apr 16, 2009
Facial reconstruction can be used as a forensic technique to identify a person, when no other ide... more Facial reconstruction can be used as a forensic technique to identify a person, when no other identification method is applicable. The facial soft tissue thickness applied to the skull is crucial when performing an accurate facial reconstruction. Historically, scientists developed several techniques to measure the soft tissue of the face. It was their aim, to build a database of a unique point-set, differentiated by gender, age, ethnic origin, BMI. All used a limited number of landmarks and an inaccurate measuring technique. We developed a contact-free and precise measuring technique, using low-dose CT and holographic data. Due to the extremely short exposure time, the holographic measurement is very precise. We lay out our first experiences to create a facial soft tissue layer map of the face.
We present an approach to generate 3-D arterial tree models based on physiological principles whi... more We present an approach to generate 3-D arterial tree models based on physiological principles while at the same time certain morphological properties are enforced at construction time in order to build individual vascular models down to the capillary level. The driving force of our approach is an angiogenesis model incorporating case-specific information about the metabolic activity in the considered domain. Additionally, we enforce morphometrically confirmed bifurcation statistics of vascular networks. The proposed method is able to generate artificial, yet physiologically plausible, arterial tree models that match the metabolic demand of the embedding tissue and fulfill the enforced morphological properties at the same time. We demonstrate the plausibility of our method on synthetic data for different metabolic configurations and analyze physiological and morphological properties of the generated tree models.
Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference, 2013
Transcatheter aortic valve implantation (TAVI) is a minimally invasive off-pump procedure to repl... more Transcatheter aortic valve implantation (TAVI) is a minimally invasive off-pump procedure to replace diseased aortic heart valves. Known complications include paravalvular leaks, atrioventricular blocks, coronary obstruction and annular rupture. Careful procedure planning including appropriate stent selection and sizing are crucial. Few patient-specific geometric parameters, like annular diameters, annular perimeter and measurement of the distance to the coronary ostia, are currently used within this process. Biomechanical simulation allows the consideration of extracted anatomy and material parameters for the intervention, which may improve planning and execution phases. We present a simulation workflow using a fully segmented aortic root anatomy, which was extracted from pre-operative CT-scan data and apply individual material models and parameters to predict the procedure outcome. Our results indicate the high relevance of calcification location and size for intervention planning...
Fast and precise shape measurement of moving objects The starting point for the development of a ... more Fast and precise shape measurement of moving objects The starting point for the development of a new shape measurement system was the request of surgeons working in the field of cranio-facial and reconstructive surgery for an improved system for precise facial measurement. For the planning and documentation of surgical interventions, information on the bone structure of the patient is needed, which is imaged by computer tomography (CT). In particular in facial surgery it is vital to the patient, that not only the functionality of the face is given, but also the appearance of the patient is restored. To account for this aspect in the planning and evaluation of surgery, the outer appearance of a patient has to be documented, hence a surface model of the face has to be generated.
For planning, simulation and documentation of interventions in maxillofacial surgery high resolvi... more For planning, simulation and documentation of interventions in maxillofacial surgery high resolving soft tissue information of the human face is needed. This information can be gained by holographic methods, which allow a recording of the whole face in an extremely short time period, so that no movement artefacts occur. In order to utilize the three-dimensional information stored in a hologram for medical applications, the hologram has to be optically reconstructed and digitized. Illumination of the hologram with the complex conjugate reference beam leads to a threedimensional real image of the recorded face, which can be digitized into a set of two-dimensional projections and merged to a three-dimensional computer model.
Medical image computing and computer-assisted intervention : MICCAI ... International Conference on Medical Image Computing and Computer-Assisted Intervention, 2011
We present an approach to generate 3-D arterial tree models based on physiological principles whi... more We present an approach to generate 3-D arterial tree models based on physiological principles while at the same time certain morphological properties are enforced at construction time in order to build individual vascular models down to the capillary level. The driving force of our approach is an angiogenesis model incorporating case-specific information about the metabolic activity in the considered domain. Additionally, we enforce morphometrically confirmed bifurcation statistics of vascular networks. The proposed method is able to generate artificial, yet physiologically plausible, arterial tree models that match the metabolic demand of the embedding tissue and fulfill the enforced morphological properties at the same time. We demonstrate the plausibility of our method on synthetic data for different metabolic configurations and analyze physiological and morphological properties of the generated tree models.
Transcatheter aortic valve implantation (TAVI) is a minimally invasive off-pump procedure to repl... more Transcatheter aortic valve implantation (TAVI) is a minimally invasive off-pump procedure to replace diseased aortic heart valves. Known complications include paravalvular leaks, atrioventricular blocks, coronary obstruction and annular rupture. Careful procedure planning including appropriate stent selection and sizing are crucial. Few patient-specific geometric parameters, like annular diameters, annular perimeter and measurement of the distance to the coronary ostia, are currently used within this process. Biomechanical simulation allows the consideration of extracted anatomy and material parameters for the intervention, which may improve planning and execution phases. We present a simulation workflow using a fully segmented aortic root anatomy, which was extracted from pre-operative CT-scan data and apply individual material models and parameters to predict the procedure outcome.
We propose a novel framework for joint 3-D vessel segmentation and centerline extraction. The app... more We propose a novel framework for joint 3-D vessel segmentation and centerline extraction. The approach is based on multivariate Hough voting and oblique random forests (RFs) that we learn from noisy annotations. It relies on steerable filters for the efficient computation of local image features at different scales and orientations. We validate both the segmentation performance and the centerline accuracy of our approach both on synthetic vascular data and four 3-D imaging datasets of the rat visual cortex at 700 nm resolution. First, we evaluate the most important structural components of our approach: (1) Orthogonal subspace filtering in comparison to steerable filters that show, qualitatively, similarities to the eigenspace filters learned from local image patches. (2) Standard RF against oblique RF. Second, we compare the overall approach to different state-of-the-art methods for (1) vessel segmentation based on optimally oriented flux (OOF) and the eigenstructure of the Hessian...
Medical image computing and computer-assisted intervention : MICCAI ... International Conference on Medical Image Computing and Computer-Assisted Intervention, 2014
This paper describes a new approach for the reconstruction of complete 3-D arterial trees from pa... more This paper describes a new approach for the reconstruction of complete 3-D arterial trees from partially incomplete image data. We utilize a physiologically motivated simulation framework to iteratively generate artificial, yet physiologically meaningful, vasculatures for the correction of vascular connectivity. The generative approach is guided by a simplified angiogenesis model, while at the same time topological and morphological evidence extracted from the image data is considered to form functionally adequate tree models. We evaluate the effectiveness of our method on four synthetic datasets using different metrics to assess topological and functional differences. Our experiments show that the proposed generative approach is superior to state-of-the-art approaches that only consider topology for vessel reconstruction and performs consistently well across different problem sizes and topologies.
For medical application in the field of maxillofacial surgery, a highly resolved 3D digital repre... more For medical application in the field of maxillofacial surgery, a highly resolved 3D digital representation of the human face is needed. Especially moving objects, i.e. infant patients are hard to capture with conventional systems. We eliminated moveable artifacts systematically by using eye safe holographic recording with short pulsed lasers (Nd:YLF laser, 526.5 nm wavelength). With a single pulse (35 ns, 1,4 J energy), surface data are recorded. Our conventional system uses an analogue process, where the hologram is reconstructed optically and digitized slice-by-slice. We explored the possibility for a complete digital process. The conventional analogue recording material is replaced by a CCD-sensor with significantly lower pulse energy (0.1 mJ) for exposure. Numerical reconstruction of the real image is performed on a computer using appropriate algorithms. Surface calculations can follow immediately. Using this digital holographic approach to measure 3D surfaces means, that processing time, costs and effort can be reduced. However, in terms of resolution, digital technology lags behind the capabilities of our current analogue method for 3D surface detection. This involves inherent limitations at the current technological state of sensor technology. Nevertheless first applications are already possible.
Proceedings of Spie the International Society For Optical Engineering, Feb 9, 2006
For planning, simulation and documentation of interventions in maxillofacial surgery high resolvi... more For planning, simulation and documentation of interventions in maxillofacial surgery high resolving soft tissue information of the human face in upright position is needed. This information can be gained by holographic methods, which allow a recording of the whole face in an extremely short time period, so that no movement artefacts occur. The hologram is recorded with a single laser pulse of 25 ns duration and stored in photosensitive material. After automated wet-chemical processing, the hologram is optically reconstructed with a cw-laser. During the optical reconstruction, a light field, which is a one-to-one three-dimensional representation of the recorded face, emerges at its original position and is digitized into a set of two-dimensional projections. Digital image processing leads to merging of these projections into a three-dimensional computer model. Besides the topometric information, a high resolving pixel precise texture is also extracted from the holographic reconstruction and used for the texturing of the computer models. The use of mirrors allows the simultaneous recording of three different views of the face with one laser pulse. The three different views of the face can be combined easily, because they are simultaneously recorded. Thus a recording range of approximately 270 degrees is achieved. In addition to the medical application, high resolving and textured computer models of faces are of tremendous importance for facial reconstruction in anthropology, forensic science and archaeology.
ABSTRACT Anatomy related heterogeneous discontinuities in material properties strongly influence h... more ABSTRACT Anatomy related heterogeneous discontinuities in material properties strongly influence human soft tissue behavior under mechanical load. We present a parametric model of the aortic root, which defines multi-material surface regions for advanced tissue property control and supports patient-specific model refinement. Our results strongly indicate improvements for in-silico clinical application experiments using multi-material simulation.
This paper describes a new approach for the reconstruction of complete 3-D arterial trees from pa... more This paper describes a new approach for the reconstruction of complete 3-D arterial trees from partially incomplete image data. We utilize a physiologically motivated simulation framework to iteratively generate artificial, yet physiologically meaningful, vasculatures for the correction of vascular connectivity. The generative approach is guided by a simplified angiogenesis model, while at the same time topological and morphological evidence extracted from the image data is considered to form functionally adequate tree models. We evaluate the effectiveness of our method on four synthetic datasets using different metrics to assess topological and functional differences. Our experiments show that the proposed generative approach is superior to state-of-the-art approaches that only consider topology for vessel reconstruction and performs consistently well across different problem sizes and topologies.
Forensic Science Medicine and Pathology, Apr 16, 2009
Facial reconstruction can be used as a forensic technique to identify a person, when no other ide... more Facial reconstruction can be used as a forensic technique to identify a person, when no other identification method is applicable. The facial soft tissue thickness applied to the skull is crucial when performing an accurate facial reconstruction. Historically, scientists developed several techniques to measure the soft tissue of the face. It was their aim, to build a database of a unique point-set, differentiated by gender, age, ethnic origin, BMI. All used a limited number of landmarks and an inaccurate measuring technique. We developed a contact-free and precise measuring technique, using low-dose CT and holographic data. Due to the extremely short exposure time, the holographic measurement is very precise. We lay out our first experiences to create a facial soft tissue layer map of the face.
We present an approach to generate 3-D arterial tree models based on physiological principles whi... more We present an approach to generate 3-D arterial tree models based on physiological principles while at the same time certain morphological properties are enforced at construction time in order to build individual vascular models down to the capillary level. The driving force of our approach is an angiogenesis model incorporating case-specific information about the metabolic activity in the considered domain. Additionally, we enforce morphometrically confirmed bifurcation statistics of vascular networks. The proposed method is able to generate artificial, yet physiologically plausible, arterial tree models that match the metabolic demand of the embedding tissue and fulfill the enforced morphological properties at the same time. We demonstrate the plausibility of our method on synthetic data for different metabolic configurations and analyze physiological and morphological properties of the generated tree models.
Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference, 2013
Transcatheter aortic valve implantation (TAVI) is a minimally invasive off-pump procedure to repl... more Transcatheter aortic valve implantation (TAVI) is a minimally invasive off-pump procedure to replace diseased aortic heart valves. Known complications include paravalvular leaks, atrioventricular blocks, coronary obstruction and annular rupture. Careful procedure planning including appropriate stent selection and sizing are crucial. Few patient-specific geometric parameters, like annular diameters, annular perimeter and measurement of the distance to the coronary ostia, are currently used within this process. Biomechanical simulation allows the consideration of extracted anatomy and material parameters for the intervention, which may improve planning and execution phases. We present a simulation workflow using a fully segmented aortic root anatomy, which was extracted from pre-operative CT-scan data and apply individual material models and parameters to predict the procedure outcome. Our results indicate the high relevance of calcification location and size for intervention planning...
Fast and precise shape measurement of moving objects The starting point for the development of a ... more Fast and precise shape measurement of moving objects The starting point for the development of a new shape measurement system was the request of surgeons working in the field of cranio-facial and reconstructive surgery for an improved system for precise facial measurement. For the planning and documentation of surgical interventions, information on the bone structure of the patient is needed, which is imaged by computer tomography (CT). In particular in facial surgery it is vital to the patient, that not only the functionality of the face is given, but also the appearance of the patient is restored. To account for this aspect in the planning and evaluation of surgery, the outer appearance of a patient has to be documented, hence a surface model of the face has to be generated.
For planning, simulation and documentation of interventions in maxillofacial surgery high resolvi... more For planning, simulation and documentation of interventions in maxillofacial surgery high resolving soft tissue information of the human face is needed. This information can be gained by holographic methods, which allow a recording of the whole face in an extremely short time period, so that no movement artefacts occur. In order to utilize the three-dimensional information stored in a hologram for medical applications, the hologram has to be optically reconstructed and digitized. Illumination of the hologram with the complex conjugate reference beam leads to a threedimensional real image of the recorded face, which can be digitized into a set of two-dimensional projections and merged to a three-dimensional computer model.
Medical image computing and computer-assisted intervention : MICCAI ... International Conference on Medical Image Computing and Computer-Assisted Intervention, 2011
We present an approach to generate 3-D arterial tree models based on physiological principles whi... more We present an approach to generate 3-D arterial tree models based on physiological principles while at the same time certain morphological properties are enforced at construction time in order to build individual vascular models down to the capillary level. The driving force of our approach is an angiogenesis model incorporating case-specific information about the metabolic activity in the considered domain. Additionally, we enforce morphometrically confirmed bifurcation statistics of vascular networks. The proposed method is able to generate artificial, yet physiologically plausible, arterial tree models that match the metabolic demand of the embedding tissue and fulfill the enforced morphological properties at the same time. We demonstrate the plausibility of our method on synthetic data for different metabolic configurations and analyze physiological and morphological properties of the generated tree models.
Transcatheter aortic valve implantation (TAVI) is a minimally invasive off-pump procedure to repl... more Transcatheter aortic valve implantation (TAVI) is a minimally invasive off-pump procedure to replace diseased aortic heart valves. Known complications include paravalvular leaks, atrioventricular blocks, coronary obstruction and annular rupture. Careful procedure planning including appropriate stent selection and sizing are crucial. Few patient-specific geometric parameters, like annular diameters, annular perimeter and measurement of the distance to the coronary ostia, are currently used within this process. Biomechanical simulation allows the consideration of extracted anatomy and material parameters for the intervention, which may improve planning and execution phases. We present a simulation workflow using a fully segmented aortic root anatomy, which was extracted from pre-operative CT-scan data and apply individual material models and parameters to predict the procedure outcome.
We propose a novel framework for joint 3-D vessel segmentation and centerline extraction. The app... more We propose a novel framework for joint 3-D vessel segmentation and centerline extraction. The approach is based on multivariate Hough voting and oblique random forests (RFs) that we learn from noisy annotations. It relies on steerable filters for the efficient computation of local image features at different scales and orientations. We validate both the segmentation performance and the centerline accuracy of our approach both on synthetic vascular data and four 3-D imaging datasets of the rat visual cortex at 700 nm resolution. First, we evaluate the most important structural components of our approach: (1) Orthogonal subspace filtering in comparison to steerable filters that show, qualitatively, similarities to the eigenspace filters learned from local image patches. (2) Standard RF against oblique RF. Second, we compare the overall approach to different state-of-the-art methods for (1) vessel segmentation based on optimally oriented flux (OOF) and the eigenstructure of the Hessian...
Medical image computing and computer-assisted intervention : MICCAI ... International Conference on Medical Image Computing and Computer-Assisted Intervention, 2014
This paper describes a new approach for the reconstruction of complete 3-D arterial trees from pa... more This paper describes a new approach for the reconstruction of complete 3-D arterial trees from partially incomplete image data. We utilize a physiologically motivated simulation framework to iteratively generate artificial, yet physiologically meaningful, vasculatures for the correction of vascular connectivity. The generative approach is guided by a simplified angiogenesis model, while at the same time topological and morphological evidence extracted from the image data is considered to form functionally adequate tree models. We evaluate the effectiveness of our method on four synthetic datasets using different metrics to assess topological and functional differences. Our experiments show that the proposed generative approach is superior to state-of-the-art approaches that only consider topology for vessel reconstruction and performs consistently well across different problem sizes and topologies.
For medical application in the field of maxillofacial surgery, a highly resolved 3D digital repre... more For medical application in the field of maxillofacial surgery, a highly resolved 3D digital representation of the human face is needed. Especially moving objects, i.e. infant patients are hard to capture with conventional systems. We eliminated moveable artifacts systematically by using eye safe holographic recording with short pulsed lasers (Nd:YLF laser, 526.5 nm wavelength). With a single pulse (35 ns, 1,4 J energy), surface data are recorded. Our conventional system uses an analogue process, where the hologram is reconstructed optically and digitized slice-by-slice. We explored the possibility for a complete digital process. The conventional analogue recording material is replaced by a CCD-sensor with significantly lower pulse energy (0.1 mJ) for exposure. Numerical reconstruction of the real image is performed on a computer using appropriate algorithms. Surface calculations can follow immediately. Using this digital holographic approach to measure 3D surfaces means, that processing time, costs and effort can be reduced. However, in terms of resolution, digital technology lags behind the capabilities of our current analogue method for 3D surface detection. This involves inherent limitations at the current technological state of sensor technology. Nevertheless first applications are already possible.
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Papers by Sven Hirsch