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Practical aspects of HIS/PACS integration with emphasis on radiological workflow

International Congress Series 2001年第C期1230卷 805-811页

作者： Feron, Michel Bellon, Erwin Vanautgaerden, Mark Deprez, Tom Pauwels, Herman Reviers, Willy Draelants, Brigitte Ghys, Swa De Deurwaerder, André Aerts, Werner Suetens, Paul Marchal, Guy Van den Bosch, Bart Department of Information Systems University Hospitals Leuven B-3000 Louvain Herestraat 49 Belgium Department of Radiology University Hospitals Leuven Louvain Belgium Medical Image Computing (ESAT/PSI and Radiology) Katholieke Universiteit Leuven Louvain Belgium

In the PACS that is now being installed for the University Hospitals Leuven, there is a strong emphasis on integration into the overall hospital-wide information system and on supporting interdepartmental workflow. In this paper, we focus on operations within the Radiology Department. We (1) motivate our emphasis on integration, (2) briefly describe our approach to integrating a commercial PACS, (3) situate some of the challenges we were faced with so far, and (4) report on initial experiences. We discuss integration into the overall workflow from the perspective of a changing emphasis in PACS. © 2001, Elsevier B.V. All rights reserved.

关键词： HIS PACS Radiological workflow

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Retrospective heel effect correction in conventional radiography

Retrospective heel effect correction in conventional radiogr...

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Workshop on Mathematical Methods in Biomedical image Analysis

作者： G. Behiels F. Maes D. Vandermeulen P. Suetens Medical Image Computing (Radiology - ESAT/PSI - LRD) University Hospital Gasthuisberg Leuven Belgium Postdoctoral Fellow of Research for the Fund for Scientific Research-Flanders (Belgium) (FWO-Vlaanderen)

ISBN: (纸本)0769513360

Three methods for retrospective correction of intensity inhomogeneities in diagnostic digital X-ray images are presented. The first method fits a theoretical heel effect model to the background intensities. The second method optimizes the parameters of a chosen image formation model to maximize the likelihood of the background pixels of the acquired image, under the assumption that their intensity values are Gaussian distributed. Additive and multiplicative linear image formation models with different degrees of freedom are fitted onto a subset of the background pixels discarding the pixels with the largest residual errors to eliminate outliers. The third method minimizes the entropy of the background and diagnostic region of the image, excluding the collimation areas. Six image formation models, using a combination of smoothly varying basis functions, are quantitatively evaluated and compared with the first method on a number of reference and real diagnostic X-ray images.

关键词： X-ray imaging Pixel Diagnostic radiography Optimization methods Entropy Collimators Humans Solid modeling Anodes Biomedical imaging

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Excess height versus cluster extent in subtraction SPECT

Excess height versus cluster extent in subtraction SPECT

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IEEE Symposium on Nuclear Science (NSS/MIC)

作者： K. Baete J. Nuyts W. Van Paesschen A. Maes S. Ghoorun P. Suetens P. Dupont Department of Nuclear Medicine University of Hospital Gasthuisberg Leuven Belgium Department of Neurology University of Hospital Gasthuisberg Leuven Belgium Department of Nuclear Medicine Tygerberg Hospital Cape Town South Africa Laboratory for Medical Image Computing Radiology-ESAT/PSI University of Hospital Gasthuisberg Leuven Belgium

Subtraction of ictal and interictal SPECT perfusion images of the brain has the potential of locating the epileptogenic region. This region generally shows large differences between both images. However, differences can also be induced by noise in the projection data. We hypothesized that the extent, besides the intensity, of observed clusters of voxels in thresholded subtraction images, is an important parameter in the classification of clusters into real perfusion differences and noise induced differences. To test this hypothesis, we performed a number of simulation experiments. Using a Monte Carlo approach, we constructed cumulative distribution functions (CDF) of the excess height (i.e. the largest difference in a cluster) and the cluster extent under the condition of no perfusion change (i.e. only noise induced clusters). The reproducibility of the CDF curves was shown using measured patient data. Furthermore, a 3D brain software phantom experiment was used to examine the detection and classification of an induced region of hyperperfusion. We assigned to every observed cluster a probability, derived from the CDF curves, for excess height and extent. For different probability thresholds, sensitivity and specificity of the detection of the induced hyperperfusion based on its probability for excess height and cluster extent was measured. These measurements were combined in receiver operating characteristic (ROC) curves. These ROC curves showed a better performance when using classification based on cluster extent. We conclude that the cluster extent is an important parameter in the characterization of clusters in thresholded subtraction of perfusion SPECT images of the brain.

关键词： Epilepsy Hospitals image analysis Single photon emission computed tomography Nuclear medicine Brain Testing Performance evaluation Monte Carlo methods Distribution functions

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Statistical shape model-based segmentation of digital X-ray images

Statistical shape model-based segmentation of digital X-ray ...

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Workshop on Mathematical Methods in Biomedical image Analysis

作者： G. Behiels D. Vandermeulen P. Suetens Faculties of Medicine and Engineering Medical Image Computing Radiology-ESAT/PSI University of Hospital Gasthuisberg Leuven Belgium

Proposes an improved search procedure for Active Shape Model (ASM) based delineation of anatomical structures in digital X-ray images and compare the original ASM search method with this new technique and a search method optimizing a Bayesian objective function, based on the prior knowledge of the statistical variation of the object boundary points and the variation of image-profiles. The original ASM search method iteratively improves the current estimate of the location of boundary points by a limited least squares adjustment of the pose and shape parameters, the authors' method additionally requires the subsequent changes in shape during the search to be smooth, which is achieved by using a minimum cost path search algorithm, while the Bayesian search methods uses the prior knowledge of the shape-model to constrain the shape parameters within acceptable limits. A number of experiments were performed to compare the accuracy and robustness of all methods using a cross-validation procedure.

关键词： image segmentation X-ray imaging Search methods Bayesian methods Active shape model Anatomical structure Optimization methods Least squares approximation Costs Iterative algorithms

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An image-based 3D planning environment for hemicricolaryngectomy and reconstruction by tracheal autotransplantation

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Computer Aided Surgery 2000年第3期5卷 166-174页

作者： Schutyser, F. Poorten, V.V. Van Cleynenbreugel, J. Delaere, P. Suetens, P. Medical Image Computing Radiology - ESAT/PSI University Hospitals of Leuven B-3000 Leuven Herestraat 49 Belgium

Objective: A new conservation method for unilateral glottal cancer with significant subglottal extension consists of a hemicricolaryngectomy and subsequent reconstruction of the laryngeal defect with a transferable patch of revascularized cervical trachea. In order to restore the three crucial functions of the larynx airway patency, speech, and swallowing the reconstructed larynx should resemble a situation with one paralyzed and one intact vocal fold at the glottal level. We hypothesize that this result can be achieved when the tracheal patch meets a typical surgical constraint the so-called paramedian position at the glottal level and when the patch is rigidly applied. This hypothesis was tested by developing and using an image-based planning system in a number of situations. Materials and Methods: An image-based surgery simulator was developed according to the working hypothesis. To validate the transfer from planning towards actual surgery, a cadaver study was set up. Based on a patient case-study, the sufficiency of the hypothesis for obtaining good functional results was evaluated. Finally, post-operative images of patients who were doing well after being operated without pre-operative planning were compared with retrospective planning to check the necessity of the hypothesis in obtaining good functionality of the neolarynx. Results: We were able to design an efficient surgery simulator. The transfer from planning towards actual surgery is accurate, and satisfactory functional results were obtained from the patient case-study. The results from the retrospective planning showed that the hypothesis is not necessary to obtain good functional results, and that the smallest possible resection is preferred from the oncological point of view. Conclusion: The working hypothesis is sufficient for good functional results, but is unnecessary and often undesirable from an oncological point of view. Important lessons are drawn concerning our long-term goal of pre-operative

关键词： Hemicricolaryngectomy image-guided therapy Surgery simulation Tracheal autograft

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An image-based 3D planning environment for hemicricolaryngectomy and reconstruction by tracheal autotransplantation

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Computer Aided Surgery 2000年第3期5卷

作者： Filip Schutyser M.Sc. Vincent Vander Poorten M.D. M.Sc. Johan Van Cleynenbreugel Ph.D. Pierre Delaere M.D., Ph.D. Paul Suetens Ph.D. Medical Image Computing (Radiology –ESAT/PSI) and Department of Oto-Rhino-Laryngology Head and Neck Surgery University Hospitals Leuven Leuven Belgium

Objective: A new conservation method for unilateral glottal cancer with significant subglottal extension consists of a hemicricolaryngectomy and subsequent reconstruction of the laryngeal defect with a transferable patch of revascularized cervical trachea. In order to restore the three crucial functions of the larynx — airway patency, speech, and swallowing — the reconstructed larynx should resemble a situation with one paralyzed and one intact vocal fold at the glottal level. We hypothesize that this result can be achieved when the tracheal patch meets a typical surgical constraint — the so-called paramedian position at the glottal level — and when the patch is rigidly applied. This hypothesis was tested by developing and using an image-based planning system in a number of situations. Materials and Methods: An image-based surgery simulator was developed according to the working hypothesis. To validate the transfer from planning towards actual surgery, a cadaver study was set up. Based on a patient case-study, the sufficiency of the hypothesis for obtaining good functional results was evaluated. Finally, post-operative images of patients who were doing well after being operated without pre-operative planning were compared with retrospective planning to check the necessity of the hypothesis in obtaining good functionality of the neolarynx. Results: We were able to design an efficient surgery simulator. The transfer from planning towards actual surgery is accurate, and satisfactory functional results were obtained from the patient case-study. The results from the retrospective planning showed that the hypothesis is not necessary to obtain good functional results, and that the smallest possible resection is preferred from the oncological point of view. Conclusion: The working hypothesis is sufficient for good functional results, but is unnecessary and often undesirable from an oncological point of view. Important lessons are drawn concerning our long-term goal of pre-o

关键词： image-guided therapy surgery simulation hemicricolaryngectomy tracheal autograft

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Metal streak artifacts in X-ray computed tomography: a simulation study

Metal streak artifacts in X-ray computed tomography: a simul...

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IEEE Symposium on Nuclear Science (NSS/MIC)

作者： B. De Man J. Nuyts P. Dupont G. Marchal P. Suetens ESAT-PSI Medical Image Computing K.U. Leuven Leuven Belgium Department of Nuclear Medicine K.U. Leuven Leuven Belgium Department of Radiology K.U. Leuven Leuven Belgium

Metal streak artifacts are an important problem in X-ray computed tomography. A high-resolution 2D fan-beam computed tomography simulator is presented. Several potential causes of metal streak artifacts are studied using phantom measurements and simulations. Beam hardening, scatter, noise and exponential edge-gradient effect are identified as important causes of metal streak artifacts. Furthermore, also aliasing effects and object motion can be responsible for certain metal streak artifacts.

关键词： Computed tomography X-ray imaging Computational modeling Brain modeling Solid modeling Detectors medical simulation Sampling methods X-ray scattering image reconstruction

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Three-Dimensional Cephalometry 1

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1000年

作者： Gwen R.J. Swennen Filip Schutyser Jarg-Erich Hausamen

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