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| 2. |
- Persson, M, et al.
(författare)
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Phase contrast MRI segmentation using multiple cues
- 2005
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Ingår i: SSBA Symposium on Image Analysis.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- This paper presents a method for three-dimensional (3D) segmentation of blood vessels, using a combination of velocity data and magnitude images obtained using phase contrast MRI. In addition to standard MRI images, phase contrast MRI gives velocity information for blood and tissue. The proposed method uses a variational formulation of the segmentation problem which combines different cues; velocity and magnitude. Experiments on phantom and clinical data support the proposed method.
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| 3. |
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| 4. |
- Bergvall, Erik, et al.
(författare)
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Regularization of phase contrast magnetic resonance images using optical flow and smoothness constraints
- 2005
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Ingår i: Computers in Cardiology. - 0276-6574. ; 32, s. 33-36
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Konferensbidrag (refereegranskat)abstract
- This paper presents a post processing strategy for myocardial velocity fields obtained by phase contrast magnetic resonance imaging. Such data can be used to track cardiac motion and to calculate strain. The method combines data regularization with optical flow estimation to overcome the partial volume effect in the image acquisition. Validation is performed both in vitro and in vivo and it is shown that the method improves the accuracy of cardiac motion tracking.
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| 5. |
- Engblom, Henrik, et al.
(författare)
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ECG-MRI based localization of myocardial infarction
- 2007
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Ingår i: Current News in Cardiology. - Milano : Springer Milan. - 9788847006355 ; , s. 347-354
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Konferensbidrag (refereegranskat)abstract
- Magnetic resonance imaging (MRI) has emerged in the last decade as an important method for characterizing various aspects of cardiac anatomy, patho-anatomy, pathophysiology, and function. Measurements of flow parameters, left ventricular function, and grade of valvular regurgitation have been validated and proved to serve as excellent gold standards compared to simpler, established techniques, such as echocardiography, thermodilution measurements, and electrocardiography.
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| 6. |
- Ericsson, Anders, et al.
(författare)
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Automated interpretation of ventilation-perfusion lung scintigrams for the diagnosis of pulmonary embolism using support vector machines
- 2003
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Ingår i: 13th Scandinavian Conference, SCIA 2003 Halmstad, Sweden, June 29 – July 2, 2003 Proceedings/Lecture Notes in Computer Science. - 0302-9743 .- 1611-3349. - 9783540406013 ; 2749, s. 415-421
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Konferensbidrag (refereegranskat)abstract
- The purpose of this study was to develop a new completely automated method for the interpretation of ventilation-perfusion (V-P) lung scintigrams for the diagnosis of pulmonary embolism. A new way of extracting features, characteristic for pulmonary embolism is presented. These features are then used as input to a Support Vector Machine, which discriminates between pulmonary embolism or no embolism. Using a material of 509 training cases and 104 test cases, the performance of the system, measured as the area under the ROC curve, was 0.86 in the test group. It is concluded that a completely automatic method can be used for interpretation of V-P scintigrams. It is faster and more robust than a previously presented method [4,5] and the accuracy is at the same level as the the previous method. It also handles abnormalities in the lungs.
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| 7. |
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| 8. |
- Hedström, Erik, et al.
(författare)
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Model based cardiac motion tracking using velocity encoded magnetic resonance imaging
- 2007
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Ingår i: Image Analysis (Lecture Notes in Computer Science). - Berlin, Heidelberg : Springer Berlin Heidelberg. - 0302-9743 .- 1611-3349. - 9783540730392 ; 4522, s. 82-91
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Konferensbidrag (refereegranskat)abstract
- This paper deals with model based regularization of velocity encoded cardiac magnetic resonance images (MRI). We extend upon an existing spatiotemporal model of cardiac kinematics by considering data certainty and regularity of the model in order to improve its performance. The method was evaluated using a computer simulated phantom and using in vivo gridtag MRI as gold standard. We show, both quantitatively and qualitatively, that our modified model performs better than the original one.
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| 9. |
- Heiberg, Einar, et al.
(författare)
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Automated Calculation of Infarct Transmurality
- 2007
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Ingår i: Computers in Cardiology 2007, vols 1 AND 2. - 0276-6574. ; , s. 165-168
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Konferensbidrag (refereegranskat)abstract
- The aim of this study was to develop all algorithm to automatically calculate infarct transmurality based oil a non dichotomous infarct classification, and to compare with manual delineation. Global transmurality as calculated by the computer algorithm were significantly smaller than the consensus delineation of three observers (p < 0.05). On a regional basis in 6 sectors of each slice the variability of the three observers compared to consensus delineation was 17%, 15%, and 20%. The variability of the automated algorithm was 16%. In conclusion, weighted calculation of transmurality gave smaller global transmurality compared to consensus delineation, but did had the same variability oil a regional basis.
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| 10. |
- Heiberg, Einar, et al.
(författare)
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Time resolved three-dimensional automated segmentation of the left ventricle
- 2005
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Ingår i: Computers in Cardiology 2005. - 0780393376 ; 32, s. 599-602
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Konferensbidrag (refereegranskat)abstract
- This paper describes a robust approach for multimodality segmentation of the cardiac left ventricle. The method is based on the concept of deformable models, but extended with an enhanced and fast edge detection scheme that includes temporal information, and anatomical a priori information. The algorithm is implemented with a fast numeric scheme for solving energy minimization, and efficient filter nets for fast edge detection. This allows clinically applicable time for a whole time resolved 3D cardiac data set to be achieved on a standard desktop computer. The algorithm is validated on images acquired using MRI gradient echo, MRI (SSFP) images, and Cardiac CT The complete algorithm is implemented into a software package freely available for non commercial research at http://segment.heiberg.se
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