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medical image computing and computer-assisted intervention, MICCAI 2004 - 7th international conference, Proceedings

作者： Lau, William W. Ramey, Nicholas A. Corso, Jason J. thakor, Nitish V. Hager, Gregory D. Department of Biomedical Engineering Johns Hopkins School of Medicine Baltimore MD United States Computational Interaction and Robotics Laboratory Johns Hopkins University Baltimore MD United States

We propose an image-based motion tracking algorithm that can be used with stereo endoscopie and microscope systems. the tracking problem is considered to be a time-varying optimization of a parametric function describing the disparity map. this algorithm could be used as part of a virtual stabilization system that can be employed to compensate residual motion of the heart during robot-assisted off-pump coronary artery bypass surgery (CABG). To test the appropriateness of our methods for this application, we processed an image sequence of a beating pig heart obtained by the stereo endoscope used in the da Vinci robotic surgery system. the tracking algorithm was able to detect the beating of the heart itself as well as the respiration of the lungs. © Springer-Verlag Berlin Heidelberg 2004.

关键词： image processing

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Measuring Biomechanical characteristics of Blood vessels for early diagnostics of vascular Retinal Pathologies

Measuring Biomechanical characteristics of Blood vessels for...

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7th international conference on medical image computing and computer-assisted intervention, MICCAI 2004

作者： Ilyasova, Nataly Yu Kupriyanov, Alexander V. Ananin, Michael A. Gavrilova, Nataly A. Image Processing Systems Institute of Russian Academy of Sciences 151 Molodogvardeiskaya st Samara443001 Russia Moscow State Medical and Stomatological University Russia

ISBN: (纸本)3540229779

A problem of early diagnostics of vascular pathologies is discussed. the method of diagnostic features estimation based on the mathematical model of a retina vessel fragment is presented. the experimental studies of the computa-tion accuracy of the global diagnostic parameters are considered. A technology for localization of the OD region and methods of estimating optic disk parame-ters are proposed. the methods proposed allow a differentiated diagnostics of the retinal diseases. © Springer-Verlag Berlin Heidelberg 2004.

关键词： Blood vessels

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Validation of dynamic heart models obtained using non-linear registration for virtual reality training, planning, and guidance of minimally invasive cardiac surgeries

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medical image ANALYSIS 2004年第3期8卷 387-401页

作者： Wierzbicki, M Drangova, M Guiraudon, G Peters, T John P Robarts Res Inst Imaging Res Labs London ON N6A 5K8 Canada Univ Western Ontario Dept Med Biophys London ON N6A 5C1 Canada CSTAR London ON N6A 5A5 Canada

Current minimally invasive techniques for beating heart surgery are associated with three major limitations: the shortage of realistic and safe training methods, the process of selecting port locations for optimal target coverage from X-rays and angiograms, and the sole use of the endoscope for instrument navigation in a dynamic and confined 3D environment. To supplement the current surgery training, planning and guidance methods, we continue-to develop our Virtual Cardiac Surgery Planning environment (VCSP) - a virtual reality, patient-specific, thoracic cavity model derived from 3D pre-procedural images. In this work, we create and validate dynamic models of the heart and its components. A static model is first generated by segmenting one of the image frames in a given 4D data set. the dynamics of this model are then extracted from the remaining image frames using a non-linear, intensity-based registration algorithm with a choice of six different similarity metrics. the algorithm is validated on an artificial CT image set created using an excised porcine heart, on CT images of canine subjects, and on MR images of human volunteers. We found that with the appropriate choice of similarity metric, our algorithm extracts the motion of the epicardial surface in CT images, or of the myocardium, right atrium, right ventricle, aorta, left atrium, pulmonary arteries, vena, cava and epicardial surface in MR images, with a root mean square error in the I rum range. these results indicate that our method of modeling the motion of the heart is easily adaptable and sufficiently accurate to meet the requirements for reliable cardiac surgery training, planning, and guidance. (C) 2004 Elsevier B.V. All rights reserved.

关键词： deformable models non-linear image registration registration validation pre-interventional planning image-guided surgery

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A study of saccade transition for attention segregation and task strategy in laparoscopic surgery

A study of saccade transition for attention segregation and ...

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medical image computing and computer-assisted intervention, MICCAI 2004 - 7th international conference, Proceedings

作者： Nicolaou, Marios James, Adam Darzi, Ara Yang, Guang-Zhong Royal Society/Wolfson Medical Image Computing Laboratory Department of Surgical Oncology and Technology Imperial College London London United Kingdom

ISBN: (纸本)3540229779

the advent and accelerated adoption of laparoscopic surgery requires an objective assessment of both operative performance and perceptual events that lead to clinical decisions. In this paper we present a framework to extract the underlying strategy through the analysis of saccadic eye-movements that lead to visual attention, and identification of intrinsic features central to the execution of basic laparoscopic tasks. Markov modeling is applied to the quantification of the saccadic eye movements for elucidating the intrinsic behaviour of the participants and the spatial-temporal evolution of visual search and hand/eye coordination characteristics. It has been found that participants adopted a unified strategy but the underlying disparity in saccadic behaviour reflect temporal and behavioural differences that could be indicative of the mental process by which the task was executed. © Springer-Verlag Berlin Heidelberg 2004.

关键词： Eye movements

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Robust generalized total least squares iterative closest point registration

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medical image computing and computer-assisted intervention, MICCAI 2004 - 7th international conference, Proceedings

作者： Estápar, Raál San Josá Brun, Anders Westin, Carl-Fredrik Laboratory of Mathematics in Imaging Brigham and Women's Hospital Harvard Medical School Boston MA United States Department of Biomedical Engineering Linköping University Sweden

ISBN: (纸本)3540229760

this paper investigates the use of a total least squares approach in a generalization of the iterative closest point (ICP) algorithm for shape registration. A new Generalized Total Least Squares (GTLS) formulation of the minimization process is presented opposed to the traditional Least Squares (LS) technique. Accounting for uncertainty both in the target and in the source models will lead to a more robust estimation of the transformation. Robustness against outliers is guaranteed by an iterative scheme to update the noise covariances. Experimental results show that this generalization is superior to the least squares counterpart. © Springer-Verlag Berlin Heidelberg 2004.

关键词： image processing

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three-dimensional shape-motion analysis of the left anterior descending coronary artery in EBCT images

Three-dimensional shape-motion analysis of the left anterior...

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medical image computing and computer-assisted intervention, MICCAI 2004 - 7th international conference, Proceedings

作者： Kakadiaris, Ioannis A. Pednekar, Amol Santamariáa-Pang, Alberto Visual Computing Lab. Dept. of Computer Science Univ. of Houston Houston TX United States

ISBN: (纸本)3540229779

In this paper, we present a physics-based deformable model framework for the quantification of shape and motion parameters of the Left Anterior Descending (LAD) coronary artery in the heart's local frame of reference. We define the long-axis of the heart as the local frame of reference. the shape of the LAD is modeled as a parametric curved axis with Frenet-Serret frame. the motion of the LAD (due to heart motion) is modeled as a composite of primitive shape-motion components: 1) longitudinal elongation, 2) radial displacement, and 3) twist with respect to the heart's local frame of reference. the three-dimensional shape-motion components are parameterized along the LAD's length. Results from simulated data and three asymptomatic subjects' Electron Beam Computed Tomography (EBCT) data are in agreement with the expected physiological trends. © Springer-Verlag Berlin Heidelberg 2004.

关键词： image analysis

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Simultaneous boundary and partial volume estimation in medical images

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7th international conference on medical Imaging and computer assisted intervention, MICCAI 2004

作者： Pham, Dzung L. Bazin, Pierre-Louis Laboratory of Medical Image Computing Johns Hopkins University BaltimoreMD21224 United States

ISBN: (纸本)3540229760

Partial volume effects are present in nearly all medical imaging data. these artifacts blur the boundaries between different regions, making accurate delineation of anatomical structures difficult. In this paper, we propose a method for unsupervised estimation of partial volume fractions in single-channel image data. Unlike previous methods, the proposed algorithm simultaneously estimates partial volume fractions, the means of the different tissue classes, as well as the the locations of tissue boundaries within the *** latter allows the partial volume fractions to be constrained to represent pure or nearly pure tissue except along tissue boundaries. We demonstrate the application of the algorithm on simulated and real magnetic resonance images. © Springer-Verlag Berlin Heidelberg 2004.

关键词： Tissue

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A study of dosimetric evaluation and feasibility of image guided intravascular brachytherapy in peripheral arteries

A study of dosimetric evaluation and feasibility of image gu...

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medical image computing and computer-assisted intervention, MICCAI 2004 - 7th international conference, Proceedings

作者： Bellec, Julien Manens, Jean-Pierre Göksu, Cemil Moisan, Cécile Haigron, Pascal CRLCC Eugène Marquis CS 44229 35042 Rennes France LTSI INSERM U642 Université de Rennes 1 35042 Rennes France Service de Chirurgie Vasculaire CHRU Rennes France

ISBN: (纸本)3540229779

this work involves the conception of the experimental dosimetric testing setup of an image based procedure for intravascular brachytherapy by 192Ir seed in peripheral arteries. After making sure of the suitability of the basis dosimetry data used for dose calculation, the treatment sequence as a whole has been tested in a customized tissue-equivalent phantom. the method is based on the use of CT preoperative images and 2D intra-operative radiographs. Experimental dosimetric results agree with the planning and demonstrate the feasibility of the procedure. © Springer-Verlag Berlin Heidelberg 2004.

关键词： Dosimetry

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Coupling statistical segmentation and PCA shape modeling

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medical image computing and computer-assisted intervention, MICCAI 2004 - 7th international conference, Proceedings

作者： Pohl, Kilian M. Warfield, Simon K. Kikinis, Ron Grimson, W. Eric L. Wells, William M. Computer Science and Artificial Intelligence Lab. Massachusetts Institute of Technology Cambridge MA United States Surgical Planning Laboratory Harvard Medical School Brigham and Women's Hospital 75 Francis St. Boston MA 02115 United States

ISBN: (纸本)3540229760

this paper presents a novel segmentation approach featuring shape constraints of multiple structures. A framework is developed combining statistical shape modeling with a maximum a posteriori segmentation problem. the shape is characterized by signed distance maps and its modes of variations are generated through principle component analysis. To solve the maximum a posteriori segmentation problem a robust Expectation Maximization implementation is used. the Expectation Maximization segmenter generates a label map, calculates image intensity inhomogeneities, and considers shape constraints for each structure of interest. Our approach enables high quality segmentations of structures with weak image boundaries which is demonstrated by automatically segmenting 32 brain MRIs into right and left thalami. © Springer-Verlag Berlin Heidelberg 2004.

关键词： image segmentation

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Multiresolution image registration based on Kullback-Leibler distance

Multiresolution image registration based on Kullback-Leibler...

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medical image computing and computer-assisted intervention, MICCAI 2004 - 7th international conference, Proceedings

作者： Gan, Rui Wu, Jue Chung, Albert C.S. Yu, Simon C.H. Wells III, William M. Department of Computer Science Hong Kong University of Science and Technology Hong Kong Hong Kong Bioengineering Program School of Engineering Hong Kong University of Science and Technology Hong Kong Hong Kong Dept. of Diagnostic Radiology and Organ Imaging Prince of Wales Hospital Hong Kong Hong Kong Brigham and Women's Hospital Harvard Medical School Boston MA United States MIT CSAI Laboratory Cambridge MA United States

this paper extends our prior work on multi-modal image registration based on the a priori knowledge of the joint intensity distribution that we expect to obtain, and Kullback-Leibler distance. this expected joint distribution can be estimated from pre-aligned training images. Experimental results show that, as compared with the Mutual Information and Approximate Maximum Likelihood based registration methods, the new method has longer capture range at different image resolutions, which can lead to a more robust image registration method. Moreover, with a simple interpolation algorithm based on non-grid point random sampling, the proposed method can avoid interpolation artifacts at the low resolution registration. Finally, it is experimentally demonstrated that our method is applicable to a variety of imaging modalities. © Springer-Verlag Berlin Heidelberg 2004.

关键词： medical imaging

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