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Extraction and analysis of large vascular networks in 3D micro-CT images

Proceedings of SPIE - The International Society for Optical Engineering 1999年 3660卷 322-334页

作者： Wan, Shu-Yen Ritman, Erik L. Higgins, William E. Pennsylvania State Univ University Park United States

High-resolution micro-CT scanners permit the generation of three-dimensional (3D) digital images containing extensive vascular networks. These images provide data needed to study the overall structure and function of such complex networks. Unfortunately, human operators have extreme difficulty in extracting the hundreds of vascular segments contained in the images. Also, no suitable network representation exists that permits straightforward structural analysis and information retrieval. This work proposes an automatic procedure for extracting and analyzing the vascular network contained in very large 3D CT images, such as can be generated by 3D micro-CT and by helical CT scanners. The procedure is efficient in terms of both execution time and memory usage. As results demonstrate, the procedure faithfully follows human-defined measurements and provides far more information than can be defined interactively.

关键词： Angiography

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3D warping and registration from lung images

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Proceedings of SPIE - The International Society for Optical Engineering 1999年 3660卷 459-470页

作者： Li, Fan Chen, Chang Wen Univ of Missouri-Columbia Columbia United States

Computerized volumetric warping and registration of 3D lung images can provide objective, accurate, and reproducible measures to the understanding of human lung structure and function. It is also invaluable to the assessment of the presence of diseases and their response to therapy. However, due to the complexity of breathing motion, little work has been carried out in this research area. In this paper, we propose a novel scheme to implement volumetric lung warping and registration from 3D CT images obtained at different stages of breathing. Bronchial points of airway trees and vessels are selected as feature points since they can be easily tracked over consecutive frames. The warping of these feature points into the entire volume is obtained based on a model of continuum mechanics and is implemented in an iteration fashion governed by such model. The model consists of three constraints: an incompressibility constraint, a divergence-free constraint and a motion-discontinuity-preserving smoothness constraint. An objective function is defined as a weighted sum of the three constraint terms and the desired displacement field of the whole volume between different stage of breathing is obtained by minimizing this objective function. The 3D warping is therefore represented by the dense displacement field obtained from the iteration. Preliminary results are visualized by overlaying the displacement field with the original images. Effectiveness of the algorithm is also evaluated by comparing the volume difference between the real and warped volumes. We believe the proposed approach will open up several areas of research in lung image analysis that can make use of the results from warping lung volumes.

关键词： Medical imaging

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Qualitative and quantitative analysis of voice onset by means of a multidimensional voice analysis system (MVAS) using high-speed imaging

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JOURNAL OF VOICE 1999年第3期13卷 355-374页

作者： Köster, O Marx, B Gemmar, P Hess, MM Künzel, HJ Univ Trier Dept Phonet Trier Germany Fachhsch Trier Dept Appl Comp Sci Trier Germany Univ Hamburg Dept Audiol & Phoniatr Hamburg Germany

High-speed filming is one of the most informative methods for assessing voice physiology data. Tracing high-speed images of the glottis provides quantitative parameters such as the glottal area and the glottal width function. By way of example, a number of studies are discussed which extract quantitative data from high-speed images showing voice onsets. Furthermore, a new computer system (MVAS;multi-dimensional voice analysis system) is presented that synchronously displays a laryngoscopic high-speed film, the electroglottographical signal, and several acoustic analyses of the recorded voice sample. The automatic measurement of glottal width and glottal area from the laryngoscopic images is also provided. Looking at former studies and our analyses of voice onsets reveals a tremendous intersubject and even intrasubject variability (different prephonatory closure, different time span until full amplitude is reached, different open quotient).

关键词： high-speed imaging multidimensional voice analysis system glottal width glottal area voice onset

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Four dimensional B-spline based motion analysis of tagged cardiac MR images

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Proceedings of SPIE - The International Society for Optical Engineering 1999年 3660卷 46-56页

作者： Ozturk, Cengizhan McVeigh, Elliot R. Johns Hopkins Univ Baltimore United States

In recent years, with development of new MRI techniques, noninvasive evaluation of global and regional cardiac function is becoming a reality. One of the methods used for this purpose is MRI tagging. In tagging, spatially encoded magnetic saturation planes, tags, are created within tissues. These act as temporary markers and move with the tissue. In cardiac tagging, tag deformation pattern provides useful qualitative and quantitative information about the functional properties of underlying myocardium. The measured deformation of a single tag plane contains only unidirectional information of the past motion. In order to track the motion of a cardiac material point, this sparse, single dimensional data has to be combined with similar information gathered from other tag sets and all time frames. Previously, several methods have been developed which rely on the specific geometry of the chambers. Here, we employ an image plane based, simple cartesian coordinate system and provide a stepwise method to describe the heart motion using a four-dimensional tensor product of B-splines. The proposed displacement and forward motion fields exhibited sub-pixel accuracy. Since our motion fields are parametric and based on an image plane based coordinate system, trajectories or other derived values (velocity, acceleration, strains...) can be calculated for any desired point on the MRI images. This method is sufficiently general so that the motion of any tagged structure can be tracked.

关键词： Medical imaging

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Use of a 4D planispheric transformation for the tracking and the analysis of LV motion with tagged MR images

Use of a 4D planispheric transformation for the tracking and...

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Proceedings of the 1999 Medical Imaging - physiology and function from multidimensional images

作者： Declerck, Jerome Ayache, Nicholas McVeigh, Elliot R. INRIA Sophia-Antipolis France

A method for reconstructing the motion of the left ventricle (LV) using 4D planispheric transformations of time and space combined in a first step with B-spline tensor products is presented. Experiments are conducted on a normal and a pathological LV to assess the tuning of the parameters of the method. The motion is analyzed as smooth zeroth and first order parameters.

关键词： Medical imaging

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Extraction and analysis of large vascular networks in 3D micro-CT images

Extraction and analysis of large vascular networks in 3D mic...

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Proceedings of the 1999 Medical Imaging - physiology and function from multidimensional images

作者： Wan, Shu-Yen Ritman, Erik L. Higgins, William E. Pennsylvania State Univ University Park PA United States

关键词： Angiography

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Multivariate approach to functional MRI analysis for brain function study

Multivariate approach to functional MRI analysis for brain f...

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Proceedings of the 1999 Medical Imaging - physiology and function from multidimensional images

作者： Lei, Tianhu Udupa, Jayaram K. Univ of Pennsylvania Philadelphia PA United States

functional MRI (fMRI) is a means of analyzing localized brain activity. It is statistically modeled by the multivariate Gaussian probability distribution (in space) and the time series (in time). However, the currently used analysis method takes an univariate approach. That is, the spatial relationships among voxels are ignored. This paper presents a multivariate analysis method. It formulates fMRI activation foci detection as a sensor-array signal processing problem and converts hypotheses tests of the univariate approach to a computer vision approach. It first creates multiple independent, identical sub-images and then uses a covariance matrix to characterize the multivariate Gaussian environment. Not only it utilizes the voxel intensities but also their spatio-temporal relationships. It achieves computer speed superiority over the existing methods. Results obtained by using simulated images, phantom images, and real fMRI data are included. The theoretical and experimental results obtained by using this approach were in good agreement.

关键词： Medical imaging

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3D warping and registration from lung images

3D warping and registration from lung images

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Proceedings of the 1999 Medical Imaging - physiology and function from multidimensional images

作者： Li, Fan Chen, Chang Wen Univ of Missouri-Columbia Columbia MO United States

关键词： Medical imaging

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Four dimensional B-spline based motion analysis of tagged cardiac MR images

Four dimensional B-spline based motion analysis of tagged ca...

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Proceedings of the 1999 Medical Imaging - physiology and function from multidimensional images

作者： Ozturk, Cengizhan McVeigh, Elliot R. Johns Hopkins Univ Baltimore MD United States

关键词： Medical imaging

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Proceedings of SPIE: Medical imaging 1998 - physiology and function from multidimensional images

Proceedings of SPIE: Medical imaging 1998 - Physiology and f...

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Medical Imaging 1998: physiology and function from multidimensional images

The proceedings contains 39 papers from SPIE: Medical Imaging 1998-physiology and function from multidimensional images. Topics discussed include: automated assessment of split lung function in post-lung-transplant evaluation;microfocal angiography of the pulmonary vasculature;optimization of CT scan with predictive contrast monitoring and automatic axis generation for 3D virtual-bronchoscopic image assessment.

关键词： Medical imaging

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