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Benčević M, Habijan M, Galić I, Babin D, Pižurica A. Understanding skin color bias in deep learning-based skin lesion segmentation. Comput Methods Programs Biomed 2024; 245:108044. [PMID: 38290289 DOI: 10.1016/j.cmpb.2024.108044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 01/17/2024] [Accepted: 01/21/2024] [Indexed: 02/01/2024]
Abstract
BACKGROUND The field of dermatological image analysis using deep neural networks includes the semantic segmentation of skin lesions, pivotal for lesion analysis, pathology inference, and diagnoses. While biases in neural network-based dermatoscopic image classification against darker skin tones due to dataset imbalance and contrast disparities are acknowledged, a comprehensive exploration of skin color bias in lesion segmentation models is lacking. It is imperative to address and understand the biases in these models. METHODS Our study comprehensively evaluates skin tone bias within prevalent neural networks for skin lesion segmentation. Since no information about skin color exists in widely used datasets, to quantify the bias we use three distinct skin color estimation methods: Fitzpatrick skin type estimation, Individual Typology Angle estimation as well as manual grouping of images by skin color. We assess bias across common models by training a variety of U-Net-based models on three widely-used datasets with 1758 different dermoscopic and clinical images. We also evaluate commonly suggested methods to mitigate bias. RESULTS Our findings expose a significant and large correlation between segmentation performance and skin color, revealing consistent challenges in segmenting lesions for darker skin tones across diverse datasets. Using various methods of skin color quantification, we have found significant bias in skin lesion segmentation against darker-skinned individuals when evaluated both in and out-of-sample. We also find that commonly used methods for bias mitigation do not result in any significant reduction in bias. CONCLUSIONS Our findings suggest a pervasive bias in most published lesion segmentation methods, given our use of commonly employed neural network architectures and publicly available datasets. In light of our findings, we propose recommendations for unbiased dataset collection, labeling, and model development. This presents the first comprehensive evaluation of fairness in skin lesion segmentation.
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Affiliation(s)
- Marin Benčević
- J. J. Strossmayer University of Osijek, Faculty of Electrical Engineering, Computer Science and Information Technology Osijek, Kneza Trpimira 2B, Osijek, 31000, Croatia; Ghent University, Department of Telecommunications and Information Processing, TELIN-GAIM, St-Pietersnieuwstraat 41, Ghent, 9000, Belgium.
| | - Marija Habijan
- J. J. Strossmayer University of Osijek, Faculty of Electrical Engineering, Computer Science and Information Technology Osijek, Kneza Trpimira 2B, Osijek, 31000, Croatia
| | - Irena Galić
- J. J. Strossmayer University of Osijek, Faculty of Electrical Engineering, Computer Science and Information Technology Osijek, Kneza Trpimira 2B, Osijek, 31000, Croatia
| | - Danilo Babin
- Ghent University, Department of Telecommunications and Information Processing, imec-TELIN-IPI, St-Pietersnieuwstraat 41, Ghent, 9000, Belgium
| | - Aleksandra Pižurica
- Ghent University, Department of Telecommunications and Information Processing, TELIN-GAIM, St-Pietersnieuwstraat 41, Ghent, 9000, Belgium
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De Winne J, Strumane A, Babin D, Luthman S, Luong H, Philips W. Multispectral indices for real-time and non-invasive tissue ischemia monitoring using snapshot cameras. Biomed Opt Express 2024; 15:641-655. [PMID: 38404312 PMCID: PMC10890856 DOI: 10.1364/boe.506084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Revised: 11/14/2023] [Accepted: 11/14/2023] [Indexed: 02/27/2024]
Abstract
An adequate supply of oxygen-rich blood is vital to maintain cell homeostasis, cellular metabolism, and overall tissue health. While classical methods of measuring tissue ischemia are often invasive, localized and require skin contact or contrast agents, spectral imaging shows promise as a non-invasive, wide field, and contrast-free approach. We evaluate three novel reflectance-based spectral indices from the 460 - 840 nm spectral range. With the aim of enabling real time visualization of tissue ischemia, information is extracted from only 2-3 spectral bands. Video-rate spectral data was acquired from arm occlusion experiments in 27 healthy volunteers. The performance of the indices was evaluated against binary Support Vector Machine (SVM) classification of healthy versus ischemic skin tissue, two other indices from literature, and tissue oxygenation estimated using spectral unmixing. Robustness was tested by evaluating these under various lighting conditions and on both the dorsal and palmar sides of the hand. A novel index with real-time capabilities using reflectance information only from 547 nm and 556 nm achieves an average classification accuracy of 88.48, compared to 92.65 using an SVM trained on all available wavelengths. Furthermore, the index has a higher accuracy compared to reference methods and its time dynamics compare well against the expected clinical responses. This holds promise for robust real-time detection of tissue ischemia, possibly contributing to improved patient care and clinical outcomes.
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Affiliation(s)
- Jens De Winne
- Department of Telecommunications and Information Processing (TELIN) - PI Research Group, Ghent University-imec, 9000 Ghent, Belgium
- Interuniversity Micro-Electronics Center (IMEC) vzw, 3000 Leuven, Belgium
| | - Anoek Strumane
- Department of Telecommunications and Information Processing (TELIN) - PI Research Group, Ghent University-imec, 9000 Ghent, Belgium
| | - Danilo Babin
- Department of Telecommunications and Information Processing (TELIN) - PI Research Group, Ghent University-imec, 9000 Ghent, Belgium
| | - Siri Luthman
- Interuniversity Micro-Electronics Center (IMEC) vzw, 3000 Leuven, Belgium
| | - Hiep Luong
- Department of Telecommunications and Information Processing (TELIN) - PI Research Group, Ghent University-imec, 9000 Ghent, Belgium
| | - Wilfried Philips
- Department of Telecommunications and Information Processing (TELIN) - PI Research Group, Ghent University-imec, 9000 Ghent, Belgium
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Van Den Berghe T, Babin D, Chen M, Callens M, Brack D, Maes H, Lievens J, Lammens M, Van Sumere M, Morbée L, Hautekeete S, Schatteman S, Jacobs T, Thooft WJ, Herregods N, Huysse W, Jaremko JL, Lambert R, Maksymowych W, Laloo F, Baraliakos X, De Craemer AS, Carron P, Van den Bosch F, Elewaut D, Jans L. Neural network algorithm for detection of erosions and ankylosis on CT of the sacroiliac joints: multicentre development and validation of diagnostic accuracy. Eur Radiol 2023; 33:8310-8323. [PMID: 37219619 DOI: 10.1007/s00330-023-09704-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 03/03/2023] [Accepted: 03/25/2023] [Indexed: 05/24/2023]
Abstract
OBJECTIVES To evaluate the feasibility and diagnostic accuracy of a deep learning network for detection of structural lesions of sacroiliitis on multicentre pelvic CT scans. METHODS Pelvic CT scans of 145 patients (81 female, 121 Ghent University/24 Alberta University, 18-87 years old, mean 40 ± 13 years, 2005-2021) with a clinical suspicion of sacroiliitis were retrospectively included. After manual sacroiliac joint (SIJ) segmentation and structural lesion annotation, a U-Net for SIJ segmentation and two separate convolutional neural networks (CNN) for erosion and ankylosis detection were trained. In-training validation and tenfold validation testing (U-Net-n = 10 × 58; CNN-n = 10 × 29) on a test dataset were performed to assess performance on a slice-by-slice and patient level (dice coefficient/accuracy/sensitivity/specificity/positive and negative predictive value/ROC AUC). Patient-level optimisation was applied to increase the performance regarding predefined statistical metrics. Gradient-weighted class activation mapping (Grad-CAM++) heatmap explainability analysis highlighted image parts with statistically important regions for algorithmic decisions. RESULTS Regarding SIJ segmentation, a dice coefficient of 0.75 was obtained in the test dataset. For slice-by-slice structural lesion detection, a sensitivity/specificity/ROC AUC of 95%/89%/0.92 and 93%/91%/0.91 were obtained in the test dataset for erosion and ankylosis detection, respectively. For patient-level lesion detection after pipeline optimisation for predefined statistical metrics, a sensitivity/specificity of 95%/85% and 82%/97% were obtained for erosion and ankylosis detection, respectively. Grad-CAM++ explainability analysis highlighted cortical edges as focus for pipeline decisions. CONCLUSIONS An optimised deep learning pipeline, including an explainability analysis, detects structural lesions of sacroiliitis on pelvic CT scans with excellent statistical performance on a slice-by-slice and patient level. CLINICAL RELEVANCE STATEMENT An optimised deep learning pipeline, including a robust explainability analysis, detects structural lesions of sacroiliitis on pelvic CT scans with excellent statistical metrics on a slice-by-slice and patient level. KEY POINTS • Structural lesions of sacroiliitis can be detected automatically in pelvic CT scans. • Both automatic segmentation and disease detection yield excellent statistical outcome metrics. • The algorithm takes decisions based on cortical edges, rendering an explainable solution.
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Affiliation(s)
- Thomas Van Den Berghe
- Department of Radiology and Medical Imaging, Ghent University Hospital, Corneel Heymanslaan 10, 9000, Ghent, Belgium.
| | - Danilo Babin
- Department of Telecommunication and Information Processing - Image Processing and Interpretation (TELIN-IPI), Faculty of Engineering and Architecture, Ghent University - IMEC, Sint-Pietersnieuwstraat 41, 9000, Ghent, Belgium
| | - Min Chen
- Department of Radiology, Peking University Shenzhen Hospital, Shenzhen, 518036, China
| | - Martijn Callens
- Department of Radiology and Medical Imaging, Ghent University Hospital, Corneel Heymanslaan 10, 9000, Ghent, Belgium
| | - Denim Brack
- Department of Radiology and Medical Imaging, Ghent University Hospital, Corneel Heymanslaan 10, 9000, Ghent, Belgium
| | - Helena Maes
- Department of Radiology and Medical Imaging, Ghent University Hospital, Corneel Heymanslaan 10, 9000, Ghent, Belgium
| | - Jan Lievens
- Department of Radiology and Medical Imaging, Ghent University Hospital, Corneel Heymanslaan 10, 9000, Ghent, Belgium
| | - Marie Lammens
- Department of Radiology and Medical Imaging, Ghent University Hospital, Corneel Heymanslaan 10, 9000, Ghent, Belgium
| | - Maxime Van Sumere
- Department of Radiology and Medical Imaging, Ghent University Hospital, Corneel Heymanslaan 10, 9000, Ghent, Belgium
| | - Lieve Morbée
- Department of Radiology and Medical Imaging, Ghent University Hospital, Corneel Heymanslaan 10, 9000, Ghent, Belgium
| | - Simon Hautekeete
- Department of Radiology and Medical Imaging, Ghent University Hospital, Corneel Heymanslaan 10, 9000, Ghent, Belgium
| | - Stijn Schatteman
- Department of Radiology and Medical Imaging, Ghent University Hospital, Corneel Heymanslaan 10, 9000, Ghent, Belgium
| | - Tom Jacobs
- Department of Radiology and Medical Imaging, Ghent University Hospital, Corneel Heymanslaan 10, 9000, Ghent, Belgium
| | - Willem-Jan Thooft
- Department of Radiology and Medical Imaging, Ghent University Hospital, Corneel Heymanslaan 10, 9000, Ghent, Belgium
| | - Nele Herregods
- Department of Radiology and Medical Imaging, Ghent University Hospital, Corneel Heymanslaan 10, 9000, Ghent, Belgium
| | - Wouter Huysse
- Department of Radiology and Medical Imaging, Ghent University Hospital, Corneel Heymanslaan 10, 9000, Ghent, Belgium
| | - Jacob L Jaremko
- Department of Radiology and Diagnostic Imaging and Rheumatology, University of Alberta, 8440 122 Street NW, Edmonton, Alberta, T6G 2B7, Canada
| | - Robert Lambert
- Department of Radiology and Diagnostic Imaging and Rheumatology, University of Alberta, 8440 122 Street NW, Edmonton, Alberta, T6G 2B7, Canada
| | - Walter Maksymowych
- Department of Radiology and Diagnostic Imaging and Rheumatology, University of Alberta, 8440 122 Street NW, Edmonton, Alberta, T6G 2B7, Canada
| | - Frederiek Laloo
- Department of Radiology and Medical Imaging, Ghent University Hospital, Corneel Heymanslaan 10, 9000, Ghent, Belgium
| | - Xenofon Baraliakos
- Rheumazentrum Ruhrgebiet Herne, Ruhr-University Bochum, Claudiusstraße 45, 44649, Herne, Germany
| | - Ann-Sophie De Craemer
- Department of Rheumatology, Ghent University Hospital, Corneel Heymanslaan 10, 9000, Ghent, Belgium
- Vlaams Instituut voor Biotechnologie (VIB) Centre for Inflammation Research (IRC), Ghent University, Technologiepark 927, 9052, Ghent, Belgium
| | - Philippe Carron
- Department of Rheumatology, Ghent University Hospital, Corneel Heymanslaan 10, 9000, Ghent, Belgium
- Vlaams Instituut voor Biotechnologie (VIB) Centre for Inflammation Research (IRC), Ghent University, Technologiepark 927, 9052, Ghent, Belgium
| | - Filip Van den Bosch
- Department of Rheumatology, Ghent University Hospital, Corneel Heymanslaan 10, 9000, Ghent, Belgium
- Vlaams Instituut voor Biotechnologie (VIB) Centre for Inflammation Research (IRC), Ghent University, Technologiepark 927, 9052, Ghent, Belgium
| | - Dirk Elewaut
- Department of Rheumatology, Ghent University Hospital, Corneel Heymanslaan 10, 9000, Ghent, Belgium
- Vlaams Instituut voor Biotechnologie (VIB) Centre for Inflammation Research (IRC), Ghent University, Technologiepark 927, 9052, Ghent, Belgium
| | - Lennart Jans
- Department of Radiology and Medical Imaging, Ghent University Hospital, Corneel Heymanslaan 10, 9000, Ghent, Belgium
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Costa M, Strumane A, Raes A, Van Soom A, Babin D, Aelterman J. Deep-Learning Based Quantification of Bovine Oocyte Quality From Microscopy Images . Annu Int Conf IEEE Eng Med Biol Soc 2023; 2023:1-4. [PMID: 38082658 DOI: 10.1109/embc40787.2023.10340258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2023]
Abstract
The success rate of bovine in vitro embryo reproduction is low and highly dependent on the oocyte quality. The selection of the oocyte to be fertilized is done by the embryologists' visual examination of oocytes. It is time-consuming, subjective, and inconsistent between specialists in the area. In this paper, a semi-automatic solution is proposed to score the quality of an immature oocyte. It consists of a deep learning model to classify oocyte competence. The model was trained and tested with real data, composed of images of immature oocytes and their label of whether they developed into blastocysts after fertilization. To the best of our knowledge, automated bovine oocyte classification was not attempted before, but experimental results show that our proposed solution is more robust and objective than specialists' visual assessment and comparable with other works on human oocytes.Clinical relevance- This establishes a semi-automatic real-time method to score bovine immature oocytes, based on stereo-microscopy images. Our method will significantly reduce the time of in vitro embryo production and its success.
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Herrera-Pereda R, Crispi AT, Babin D, Philips W. Segmentation of endothelial cells of the cornea from the distance map of confocal microscope images. Comput Biol Med 2021; 139:104953. [PMID: 34735943 DOI: 10.1016/j.compbiomed.2021.104953] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2021] [Revised: 10/14/2021] [Accepted: 10/15/2021] [Indexed: 11/28/2022]
Abstract
We propose a novel algorithm for segmenting cells of the cornea endothelium layer on confocal microscope images. To get an inter-cellular space with minimum gray-scale value and to enhance cell borders, we apply a difference of Gaussian filter before image binarization by thresholding with the minimum gray-scale value. Removal of segmented noise and artifacts is performed by automatic thresholding (using an image frequency analysis to obtain a global threshold value per image). Final segmentation of cells is achieved by fitting the largest inscribed circles into the centers of cell regions defined by the distance map of the binary images. Parameters of interest such as cell count and density, pleomorphism, polymegathism, and F-measure are computed on a publicly available data-set (Confocal Corneal Endothelial Microscopy Data Set - Rotterdam Ophthalmic Data Repository) and compared against the results of the segmentation methods included with the data set, and the results of state of the art automatic methods. The obtained results achieve higher accuracy compared to the results of the segmentation included with the data set (e.g., -proposed versus dataset in R2 and mean relative error-, cell count: 0.823, - 0.241 versus 0.017, 0.534; cell density: 0.933, - 0.067 versus 0.154, 0.639; cell polymegathism: 0.652, - 0.079 versus 0.075, 0.886; cell pleomorphism: 0.242, - 0.128 versus 0.0352, - 0.222, respectively), and are in good agreement with the results of the state of the art method.
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Affiliation(s)
- Raidel Herrera-Pereda
- Departamento de Bioinformática, Facultad de Ciencias y Tecnologías Computacionales, Universidad de las Ciencias Informáticas (UCI), Carretera a San Antonio de los Baños Km 2 ½, Torrens, Boyeros, La Habana, Cuba; TELIN-IPI, Ghent University - imec, Belgium.
| | - Alberto Taboada Crispi
- Centro de Investigaciones de la Informática, Universidad Central "Marta Abreu" de Las Villas (UCLV), Carretera a Camajuaní, km 5 ½, Santa Clara, VC, CP 54830, Cuba
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Herrera-Pereda R, Taboada Crispi A, Babin D, Philips W, Holsbach Costa M. A Review On digital image processing techniques for in-Vivo confocal images of the cornea. Med Image Anal 2021; 73:102188. [PMID: 34340102 DOI: 10.1016/j.media.2021.102188] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 06/12/2021] [Accepted: 07/16/2021] [Indexed: 12/27/2022]
Abstract
This work reviews the scientific literature regarding digital image processing for in vivo confocal microscopy images of the cornea. We present and discuss a selection of prominent techniques designed for semi- and automatic analysis of four areas of the cornea (epithelium, sub-basal nerve plexus, stroma and endothelium). The main context is image enhancement, detection of structures of interest, and quantification of clinical information. We have found that the preprocessing stage lacks of quantitative studies regarding the quality of the enhanced image, or its effects in subsequent steps of the image processing. Threshold values are widely used in the reviewed methods, although generally, they are selected empirically and manually. The image processing results are evaluated in many cases through comparison with gold standards not widely accepted. It is necessary to standardize values to be quantified in terms of sensitivity and specificity of methods. Most of the reviewed studies do not show an estimation of the computational cost of the image processing. We conclude that reliable, automatic, computer-assisted image analysis of the cornea is still an open issue, constituting an interesting and worthwhile area of research.
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Affiliation(s)
- Raidel Herrera-Pereda
- Departamento de Bioinformática, Facultad de Ciencias y Tecnologías Computacionales, Universidad de las Ciencias Informáticas (UCI), Carretera a San Antonio de los Baños Km 2 1/2, Torrens, Boyeros, La Habana, Cuba; TELIN-IPI, Ghent University - imec, Belgium.
| | - Alberto Taboada Crispi
- Centro de Investigaciones de la Informática, Universidad Central "Marta Abreu" de Las Villas (UCLV), Carretera a Camajuaní, km 5 1/2, Santa Clara, VC, CP 54830, Cuba
| | | | | | - Márcio Holsbach Costa
- Department of Electrical and Electronic Engineering, Federal University of Santa Catarina, Florianópolis, SC, Brazil
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Argacha JF, Decamp J, Vandeloo B, Babin D, Lochy S, Van den Bussche K, de Hemptinne Q, Xaplanteris P, Magne J, Segers P, Cosyns B. Guiding Myocardial Revascularization by Algorithmic Interpretation of FFR Pullback Curves: A Proof of Concept Study. Front Cardiovasc Med 2021; 8:623841. [PMID: 33778020 PMCID: PMC7990785 DOI: 10.3389/fcvm.2021.623841] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Accepted: 02/19/2021] [Indexed: 01/09/2023] Open
Abstract
Background: Coronary artery disease distribution along the vessel is a main determinant of FFR improvement after PCI. Identifying focal from diffuse disease from visual inspections of coronary angiogram (CA) and FFR pullback (FFR-PB) are operator-dependent. Computer science may standardize interpretations of such curves. Methods: A virtual stenting algorithm (VSA) was developed to perform an automated FFR-PB curve analysis. A survey analysis of the evaluations of 39 vessels with intermediate disease on CA and a distal FFR <0.8, rated by 5 interventional cardiologists, was performed. Vessel disease distribution and PCI strategy were successively rated based on CA and distal FFR (CA); CA and FFR-PB curve (CA/FFR-PB); and CA and VSA (CA/VSA). Inter-rater reliability was assessed using Fleiss kappa and an agreement analysis of CA/VSA rating with both algorithmic and human evaluation (operator) was performed. We hypothesize that VSA would increase rater agreement in interpretation of epicardial disease distribution and subsequent evaluation of PCI eligibility. Results: Inter-rater reliability in vessel disease assessment by CA, CA/FFR-PB, and CA/VSA were respectively, 0.32 (95% CI: 0.17-0.47), 0.38 (95% CI: 0.23-0.53), and 0.4 (95% CI: 0.25-0.55). The raters' overall agreement in vessel disease distribution and PCI eligibility was higher with the VSA than with the operator (respectively, 67 vs. 42%, and 80 vs. 70%, both p < 0.05). Compared to CA/FFR-PB, CA/VSA induced more reclassification toward a focal disease (92 vs. 56.2%, p < 0.01) with a trend toward more reclassification as eligible for PCI (70.6 vs. 33%, p = 0.06). Change in PCI strategy did not differ between CA/FFR-PB and CA/VSA (23.6 vs. 28.5%, p = 0.38). Conclusions: VSA is a new program to facilitate and standardize the FFR pullback curves analysis. When expert reviewers integrate VSA data, their assessments are less variable which might help to standardize PCI eligibility and strategy evaluations. Clinical Trial Registration: https://www.clinicaltrials.gov/ct2/show/NCT03824600.
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Affiliation(s)
- Jean-François Argacha
- Department of Cardiology, Universitair Ziekenhuis Brussel, Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Jean Decamp
- Centre for Quantum Technologies, National University of Singapore, Singapore, Singapore
| | - Bert Vandeloo
- Department of Cardiology, Universitair Ziekenhuis Brussel, Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Danilo Babin
- imec-TELIN-IPI, Ghent University, Ghent, Belgium
| | - Stijn Lochy
- Department of Cardiology, Universitair Ziekenhuis Brussel, Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Karen Van den Bussche
- Department of Cardiology, Universitair Ziekenhuis Brussel, Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Quentin de Hemptinne
- Department of Cardiology, Centre Hospitalier Universitaire (CHU) Saint-Pierre, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Panagiotis Xaplanteris
- Department of Cardiology, Centre Hospitalier Universitaire (CHU) Saint-Pierre, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Julien Magne
- Department of Cardiology, Dupuytren University Hospital 2, Limoges, France.,INSERM U1094 and IRD, Limoges University, Limoges, France
| | - Patrick Segers
- Department of Electronics and Information Systems, IBiTech-bioMMeda, Ghent University, Ghent, Belgium
| | - Bernard Cosyns
- Department of Cardiology, Universitair Ziekenhuis Brussel, Vrije Universiteit Brussel (VUB), Brussels, Belgium
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Habijan M, Babin D, Galić I, Leventić H, Romić K, Velicki L, Pižurica A. Overview of the Whole Heart and Heart Chamber Segmentation Methods. Cardiovasc Eng Technol 2020; 11:725-747. [DOI: 10.1007/s13239-020-00494-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Accepted: 10/06/2020] [Indexed: 12/13/2022]
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Leventić H, Babin D, Velicki L, Devos D, Galić I, Zlokolica V, Romić K, Pižurica A. Left atrial appendage segmentation from 3D CCTA images for occluder placement procedure. Comput Biol Med 2019; 104:163-174. [DOI: 10.1016/j.compbiomed.2018.11.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Revised: 10/29/2018] [Accepted: 11/07/2018] [Indexed: 11/29/2022]
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Zlokolica V, Krstanović L, Velicki L, Popović B, Janev M, Obradović R, Ralević NM, Jovanov L, Babin D. Semiautomatic Epicardial Fat Segmentation Based on Fuzzy c-Means Clustering and Geometric Ellipse Fitting. J Healthc Eng 2017; 2017:5817970. [PMID: 29083420 PMCID: PMC5632458 DOI: 10.1155/2017/5817970] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Revised: 08/06/2017] [Accepted: 08/20/2017] [Indexed: 01/10/2023]
Abstract
Automatic segmentation of particular heart parts plays an important role in recognition tasks, which is utilized for diagnosis and treatment. One particularly important application is segmentation of epicardial fat (surrounds the heart), which is shown by various studies to indicate risk level for developing various cardiovascular diseases as well as to predict progression of certain diseases. Quantification of epicardial fat from CT images requires advance image segmentation methods. The problem of the state-of-the-art methods for epicardial fat segmentation is their high dependency on user interaction, resulting in low reproducibility of studies and time-consuming analysis. We propose in this paper a novel semiautomatic approach for segmentation and quantification of epicardial fat from 3D CT images. Our method is a semisupervised slice-by-slice segmentation approach based on local adaptive morphology and fuzzy c-means clustering. Additionally, we use a geometric ellipse prior to filter out undesired parts of the target cluster. The validation of the proposed methodology shows good correspondence between the segmentation results and the manual segmentation performed by physicians.
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Affiliation(s)
- Vladimir Zlokolica
- Department of Fundamentals Sciences, Faculty of Technical Sciences, University of Novi Sad, Trg Dositeja Obradovića 6, 21000 Novi Sad, Serbia
| | - Lidija Krstanović
- Department of Fundamentals Sciences, Faculty of Technical Sciences, University of Novi Sad, Trg Dositeja Obradovića 6, 21000 Novi Sad, Serbia
| | - Lazar Velicki
- Faculty of Medicine, University of Novi Sad, Hajduk Veljkova 3, 21000 Novi Sad, Serbia
| | - Branislav Popović
- Department of Power, Electronic and Telecommunication Engineering, Faculty of Technical Sciences, University of Novi Sad, Trg Dositeja Obradovića 6, 21000 Novi Sad, Serbia
| | - Marko Janev
- Mathematical Institute, Serbian Academy of Arts and Sciences, Kneza Mihaila 36, 11000 Beograd, Serbia
| | - Ratko Obradović
- Department of Fundamentals Sciences, Faculty of Technical Sciences, University of Novi Sad, Trg Dositeja Obradovića 6, 21000 Novi Sad, Serbia
| | - Nebojsa M. Ralević
- Department of Fundamentals Sciences, Faculty of Technical Sciences, University of Novi Sad, Trg Dositeja Obradovića 6, 21000 Novi Sad, Serbia
| | - Ljubomir Jovanov
- Faculty of Engineering and Architecture, imec-IPI-UGent, Ghent University, Sint-Pietersnieuwstraat 41, 9000 Gent, Belgium
| | - Danilo Babin
- Faculty of Engineering and Architecture, imec-IPI-UGent, Ghent University, Sint-Pietersnieuwstraat 41, 9000 Gent, Belgium
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Devos DGH, De Groote K, Babin D, Demulier L, Taeymans Y, Westenberg JJ, Van Bortel L, Segers P, Achten E, De Schepper J, Rietzschel E. Proximal aortic stiffening in Turner patients may be present before dilation can be detected: a segmental functional MRI study. J Cardiovasc Magn Reson 2017; 19:27. [PMID: 28222756 PMCID: PMC5320803 DOI: 10.1186/s12968-017-0331-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Accepted: 01/20/2017] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND To study segmental structural and functional aortic properties in Turner syndrome (TS) patients. Aortic abnormalities contribute to increased morbidity and mortality of women with Turner syndrome. Cardiovascular magnetic resonance (CMR) allows segmental study of aortic elastic properties. METHOD We performed Pulse Wave Velocity (PWV) and distensibility measurements using CMR of the thoracic and abdominal aorta in 55 TS-patients, aged 13-59y, and in a control population (n = 38;12-58y). We investigated the contribution of TS on aortic stiffness in our entire cohort, in bicuspid (BAV) versus tricuspid (TAV) aortic valve-morphology subgroups, and in the younger and older subgroups. RESULTS Differences in aortic properties were only seen at the most proximal aortic level. BAV Turner patients had significantly higher PWV, compared to TAV Turner (p = 0.014), who in turn had significantly higher PWV compared to controls (p = 0.010). BAV Turner patients had significantly larger ascending aortic (AA) luminal area and lower AA distensibility compared to both controls (all p < 0.01) and TAV Turner patients. TAV Turner had similar AA luminal areas and AA distensibility compared to Controls. Functional changes are present in younger and older Turner subjects, whereas ascending aortic dilation is prominent in older Turner patients. Clinically relevant dilatation (TAV and BAV) was associated with reduced distensibility. CONCLUSION Aortic stiffening and dilation in TS affects the proximal aorta, and is more pronounced, although not exclusively, in BAV TS patients. Functional abnormalities are present at an early age, suggesting an aortic wall disease inherent to the TS. Whether this increased stiffness at young age can predict later dilatation needs to be studied longitudinally.
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Affiliation(s)
- Daniel G. H. Devos
- Department of Radiology, MRI (-1K12), Ghent University Hospital, De Pintelaan 185, B-9000 Gent, Belgium
| | - Katya De Groote
- Pediatric Cardiology, Department of Pediatrics and Turner Clinic, Ghent University Hospital, De Pintelaan 185, B-9000 Gent, Belgium
| | - Danilo Babin
- Telecommunications and Information Processing, TELIN-IPI-iMinds, Faculty of Engineering and Architecture, Ghent University, Sint-Pietersnieuwstraat 41, 9000 Ghent, Belgium
| | - Laurent Demulier
- Department of Cardiology, Ghent University Hospital, De Pintelaan 185, B-9000 Gent, Belgium
| | - Yves Taeymans
- Department of Cardiology, Ghent University Hospital, De Pintelaan 185, B-9000 Gent, Belgium
| | - Jos J. Westenberg
- Department of Radiology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden, The Netherlands
| | - Luc Van Bortel
- Heymans Institute of Pharmacology, Ghent University Hospital, De Pintelaan 185, B-9000 Gent, Belgium
| | - Patrick Segers
- IBiTech-bioMMeda, Ghent University Hospital, De Pintelaan 185, B-9000 Gent, Belgium
| | - Eric Achten
- Department of Radiology, MRI (-1K12), Ghent University Hospital, De Pintelaan 185, B-9000 Gent, Belgium
| | - Jean De Schepper
- Pediatric Endocrinology, Department of Pediatrics and Turner Clinic, Ghent University Hospital, De Pintelaan 185, B-9000 Gent, Belgium
| | - Ernst Rietzschel
- Department of Cardiology, Ghent University Hospital, De Pintelaan 185, B-9000 Gent, Belgium
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Greulich S, Meloni A, Nazir SA, Stefan Biesbroek P, Arenja N, Kammerlander AA, Sayeed A, Ricci F, Bernhardt P, Meierhofer C, Devos DG, Ruecker B, Burkhardt B, Kamphuis VP, De Lazzari M, Nederend I, Dux-Santoy L, Cavalcante JL, Rosmini S, Liu B, Fent G, Claessen G, Behar J, Oebel S, Baritussio A, Ranjit Arnold J, Kitterer D, Latus J, Henes J, Kurmann R, Gloekler S, Wahl A, Buss S, Katus H, Bobbo M, Lombardi M, Braun N, Alscher M, Sechtem U, Mahrholdt H, Neri M, Preziosi P, Grassedonio E, Schicchi N, Keilberg P, Pulini S, Facchini E, Positano V, Pepe A, Shetye A, Khan JN, Singh A, Kanagala P, Swarbrick D, Gulsin G, Graham-Brown M, Squire I, Gershlick A, McCann GP, Amier RP, Teunissen PF, Robbers LF, Beek AM, van Rossum AC, Hofman MB, van Royen N, Nijveldt R, Riffel JH, Djiokou CN, Andre F, Fritz T, Halder M, Thomas Z, Korosoglou G, Katus HA, Buss SJ, Schwaiger ML, Duca F, Aschauer S, Marzluf BA, Zotter-Tufaro C, Dalos D, Pfaffenberger S, Bonderman D, Mascherbauer J, Fridman Y, Hackman B, Kadakkal A, Maanja M, Daya HA, Wong TC, Schelbert EB, Barison A, Todiere G, Gaeta R, Galllina S, Emdin M, De Caterina R, Aquaro G, Buckert D, Dyckmanns N, Rottbauer W, Kühn A, Shehu N, Müller J, Stern H, Ewert P, Fratz S, Vogt M, De Groote K, Babin D, Demulier L, Taeymans Y, Westenberg JJ, Van Bortel L, Segers P, Achten E, De Schepper J, Rietzschel E, Geiger J, Makki M, Burkhardt B, Kellenberger CJ, Buechel ERV, Kellenberger C, Geiger J, Ruecker B, Buechel EV, Elbaz MS, Kroft LJ, van der Geest RJ, de Roos A, Blom NA, Westenberg JJ, Roest AA, Cipriani A, Susana A, Rizzo S, Giorgi B, Carmelo L, Bertaglia E, Bauce B, Corrado D, Thiene G, Marra MP, Basso C, Iliceto S, Roest A, van den Boogaard P, ten Harkel A, de Geus J, Kroft L, de Roos A, Westenberg J, Kale R, Teixido-Tura G, Maldonado G, Huguet M, Garcia-Dorado D, Evangelista A, Rodriguez-Palomares J, Rijal S, Schindler JT, Gleason TG, Lee JS, Schelbert EB, Bulluck H, Treibel TA, Bhuva A, Abdel-Gadir A, Culotta V, Merghani A, Maestrini V, Herrey AS, Kellman P, Manisty C, Moon JC, Hayer M, Baig S, Shah T, Rooney S, Edwards N, Steeds R, Garg P, Swoboda P, Dobson L, Musa T, Foley J, Haaf P, Greenwood J, Plein S, Schnell F, Bogaert J, Dymarkowski S, Pattyn N, Claus P, Van Cleemput J, Gerche AL, Heidbuchel H, Toth D, Reiml S, Panayiotou M, Claridge S, Jackson T, Sohal M, Webb J, O'Neill M, Brost A, Mountney P, Razavi R, Rhode K, Rinaldi CA, Arya A, Hilbert S, Bollmann A, Hindricks G, Jahnke C, Paetsch I, Dinov B, Perazzolo Marra M, Ghosh Dastidar A, Rodrigues J, Zorzi A, Susana A, Scatteia A, De Garate E, Mattesi G, Strange J, Corrado D, Bucciarelli-Ducci C, Jerosch-Herold M, Karamitsos TD, Francis JM, Bhamra-Ariza P, Sarwar R, Choudhury R, Selvanayagam JB, Neubauer S. ORAL AB AGORA1362Cardiac Involvement in Patients With Different Rheumatic Disorders1366Gender differences in the development of cardiac complications: a multicentric prospective study in a large cohort of thalassemia major patients1646Comparison of T1-mapping, T2-weighted and contrast-enhanced cine imaging at 3.0T CMR for diagnostic oedema assessment in ST-segment elevation myocardial infarction1375Evaluation of Tissue Changes in Remote Noninfarcted Myocardium after Acute Myocardial Infarction using T1-mapping1377Right ventricular long axis strain – The prognostic value of a novel parameter in non-ischemic dilated cardiomyopathy using standard cardiac magnetic resonance imaging1389The role of the right ventricular insertion point in heart failure patients with preserved ejection fraction: Insights from a cardiovascular magnetic resonance study1398Myocardial fibrosis associates with B-type natriuretic peptide levels and outcomes more than wall stress1478Prognostic Value of Pulmonary Blood Volume by Contrast-Enhanced Magnetic Resonance Imaging in Heart Failure Outpatients – The PROVE-HF Study1370Magnetic Resonance Adenosine Perfusion Imaging as Gatekeeper of Invasive Coronary1509Influence of non-invasive hemodynamic CMR parameters on maximal exercise capacity in surgically untreated patients with Ebstein's anomaly1356Proximal aortic stiffening in Turner patients is more pronounced in the presence of a bicuspid valve. A segmental functional MRI study1503Flow pattern and vascular distensibility of the pulmonary arteries in patients after repair of tetralogy of Fallot. Insights from 4D flow CMR1516Myocardial deformation characteristics of the systemic right ventricle after atrial switch operation for transposition of the great arteries1633Three-dimensional vortex formation in patients with a Fontan circulation: evaluation with 4D flow CMR1483Mitral valve prolapse: arrhythmogenic substrates by cardiac magnetic imaging1596Increased local wall shear stress after coarctation repair is associated with descending aorta pulse wave velocity: evaluation with CMR and 4D flow1636Three-dimensional wall shear stress assessed by 4Dflow CMR in bicuspid aortic valve disease1464Cardiac Amyloidosis and Aortic Stenosis – The Convergence of Two Aging Processes1630Blood T1 variability explained in healthy volunteers: an analysis on MOLLI, ShMOLLI and SASHA1408Myocardial deformation on CMR predicts adverse outcomes in carcinoid heart disease - a new marker of risk1492Myocardial Perfusion Reserve and Global Longitudinal Strain in Early Rheumatoid Arthritis1500Exercise CMR to differentiate athlete's heart from patients with early dilated cardiomyopathy1559Real-Time, x-mri guidance to optimise left ventricular lead placement for delivery of cardiac resynchronisation therapy1560The role of Cardiac magnetic resonance imaging in patients undergoing ablation for ventricular tachycardia- Defining the substrate and visualizing the outcome1590Impact of cardiovascular magnetic resonance on clinical management and decision-making of out of hospital cardiac arrest survivors with inconclusive coronary angiogram1561Detection of coronary stenosis at rest using Oxygenation-Sensitive Magnetic Resonance Imaging. Eur Heart J Cardiovasc Imaging 2016. [DOI: 10.1093/ehjci/jew181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Devos DGH, Rietzschel E, Heyse C, Vandemaele P, Van Bortel L, Babin D, Segers P, Westenberg JM, Achten R. MR pulse wave velocity increases with age faster in the thoracic aorta than in the abdominal aorta. J Magn Reson Imaging 2014; 41:765-72. [PMID: 24615998 DOI: 10.1002/jmri.24592] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Accepted: 01/10/2014] [Indexed: 11/09/2022] Open
Abstract
PURPOSE To assess the difference between thoracic and abdominal aortic pulse wave velocity (PWV) in apparently healthy subjects including young adults to elderly subjects. MATERIALS AND METHODS We performed PWV and distensibility measurements and analysis of thoracic and abdominal aortic segments in 96 apparently normal subjects aged 20-80 years with magnetic resonance (MR). Both unadjusted correlation and General Linear Model (GLM) analysis of log-transformed PWV (thoracic and abdominal aorta) and distensibility (four aortic cross-sections) were performed. RESULTS Both thoracic and abdominal PWV values and distensibility values increased with age. In unadjusted analyses the correlation between the ln(thoracic PWV) and age (r = 0.71; P < 0.001) was stronger than between ln(abdominal PWV) and age (r = 0.50; P < 0.001). In GLM analysis, the only determinant of thoracic and abdominal PWV was age (F = 42.5 and F = 14.8, respectively; both P < 0.001). Similarly, correlation between ln(distensibility) and age was strong (r = -0.79, r = -0.67, r = -0.71, and r = -0.65 for ascending, descending, diaphragmatic, and low abdominal aorta, respectively; all P < 0.001). In GLM analysis, age was the major determinant for distensibility of the ascending aorta (F = 81.7; P < 0.001), descending aorta (F = 42.2; P < 0.001), diaphragmatic aorta (F = 39.2; P < 0.001), and low abdominal aorta (F = 32.8; P < 0.001). CONCLUSION The thoracic aorta is less stiff than the abdominal aorta in young and middle-aged subjects, and stiffens more rapidly with age than the abdominal aorta, resulting in a stiffer thoracic than abdominal aorta at older age.
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Affiliation(s)
- Daniel G H Devos
- Department of Radiology, MRI (-1K12), University Hospital Ghent, De Pintelaan 185, B-9000, Gent, Belgium
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Babin D, Devos D, Pižurica A, Westenberg J, Vansteenkiste E, Philips W. Robust segmentation methods with an application to aortic pulse wave velocity calculation. Comput Med Imaging Graph 2014; 38:179-89. [PMID: 24405817 DOI: 10.1016/j.compmedimag.2013.12.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2013] [Revised: 11/06/2013] [Accepted: 12/09/2013] [Indexed: 10/25/2022]
Abstract
Aortic stiffness has proven to be an important diagnostic and prognostic factor of many cardiovascular diseases, as well as an estimate of overall cardiovascular health. Pulse wave velocity (PWV) represents a good measure of the aortic stiffness, while the aortic distensibility is used as an aortic elasticity index. Obtaining the PWV and the aortic distensibility from magnetic resonance imaging (MRI) data requires diverse segmentation tasks, namely the extraction of the aortic center line and the segmentation of aortic regions, combined with signal processing methods for the analysis of the pulse wave. In our study non-contrasted MRI images of abdomen were used in healthy volunteers (22 data sets) for the sake of non-invasive analysis and contrasted magnetic resonance (MR) images were used for the aortic examination of Marfan syndrome patients (8 data sets). In this research we present a novel robust segmentation technique for the PWV and aortic distensibility calculation as a complete image processing toolbox. We introduce a novel graph-based method for the centerline extraction of a thoraco-abdominal aorta for the length calculation from 3-D MRI data, robust to artifacts and noise. Moreover, we design a new projection-based segmentation method for transverse aortic region delineation in cardiac magnetic resonance (CMR) images which is robust to high presence of artifacts. Finally, we propose a novel method for analysis of velocity curves in order to obtain pulse wave propagation times. In order to validate the proposed method we compare the obtained results with manually determined aortic centerlines and a region segmentation by an expert, while the results of the PWV measurement were compared to a validated software (LUMC, Leiden, the Netherlands). The obtained results show high correctness and effectiveness of our method for the aortic PWV and distensibility calculation.
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Affiliation(s)
- Danilo Babin
- Department of Telecommunications and Information Processing - TELIN-IPI-iMinds, Faculty of Sciences, Ghent University, Sint-Pietersnieuwstraat 41, B-9000 Ghent, Belgium.
| | - Daniel Devos
- Department of Radiology, Cardiovascular MR & CT, Ghent University Hospital, De Pintelaan 185, B-9000 Ghent, Belgium.
| | - Aleksandra Pižurica
- Department of Telecommunications and Information Processing - TELIN-IPI-iMinds, Faculty of Sciences, Ghent University, Sint-Pietersnieuwstraat 41, B-9000 Ghent, Belgium.
| | - Jos Westenberg
- Department of Radiology, LUMC, Leiden University Medical Center, Albinusedreef 2, 2333 ZA Leiden, The Netherlands.
| | - Ewout Vansteenkiste
- Department of Telecommunications and Information Processing - TELIN-IPI-iMinds, Faculty of Sciences, Ghent University, Sint-Pietersnieuwstraat 41, B-9000 Ghent, Belgium.
| | - Wilfried Philips
- Department of Telecommunications and Information Processing - TELIN-IPI-iMinds, Faculty of Sciences, Ghent University, Sint-Pietersnieuwstraat 41, B-9000 Ghent, Belgium.
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Babin D, Vansteenkiste E, Pižurica A, Philips W. Centerline calculation for extracting abdominal aorta in 3-D MRI images. Annu Int Conf IEEE Eng Med Biol Soc 2013; 2012:3982-5. [PMID: 23366800 DOI: 10.1109/embc.2012.6346839] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The examination of abdominal aorta is an effective way to diagnose many cardiovascular diseases. Aortic stiffness measured by pulse wave velocity (PWV) calculation is a good estimate of overall cardiovascular health. Calculation of pulse wave velocity requires the length of abdominal aorta as an input parameter, while the structure of abdominal aorta can be used for diagnostic purposes. For the sake of non-invasive diagnostics, non-contrasted MRI images of aorta were used. Due to the "black-blood" imaging, a lot of artifacts are present and a robust centerline extraction method is needed. In this research we develop a novel graph-based method for extracting centerlines of abdominal aorta for length calculation. Our method is robust to artifacts and noise and applicable to any imaging modality.
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Affiliation(s)
- Danilo Babin
- Department of Telecommunications and Information Processing-TELIN-IPI-IBBT, Faculty of Sciences, Ghent University, Sint-Pietersnieuwstraat 41, B-9000 Ghent, Belgium.
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Babin D, Vansteenkiste E, Pizurica A, Philips W. Segmentation of brain blood vessels using projections in 3-D CT angiography images. Annu Int Conf IEEE Eng Med Biol Soc 2011; 2011:8475-8478. [PMID: 22256315 DOI: 10.1109/iembs.2011.6092091] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Segmenting cerebral blood vessels is of great importance in diagnostic and clinical applications, especially in quantitative diagnostics and surgery on aneurysms and arteriovenous malformations (AVM). Segmentation of CT angiography images requires algorithms robust to high intensity noise, while being able to segment low-contrast vessels. Because of this, most of the existing methods require user intervention. In this work we propose an automatic algorithm for efficient segmentation of 3-D CT angiography images of cerebral blood vessels. Our method is robust to high intensity noise and is able to accurately segment blood vessels with high range of luminance values, as well as low-contrast vessels.
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Affiliation(s)
- Danilo Babin
- Department of Telecommunications and Information Processing-TELIN-IPI-IBBT, Faculty of Sciences, Ghent University, Sint-Pietersnieuwstraat 41, B-9000 Ghent, Belgium.
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Babin D, Vansteenkiste E, Pizurica A, Philips W. Segmentation of airways in lungs using projections in 3-D CT angiography images. Annu Int Conf IEEE Eng Med Biol Soc 2010; 2010:3162-3165. [PMID: 21096807 DOI: 10.1109/iembs.2010.5627401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
In diagnosing lung diseases, the structure and shape of airways in lungs are of great importance. In this paper we propose a novel method for segmenting low-contrast 3-D CTA images of airways in lungs. Our approach is an edge-detecting slice-by-slice segmentation method, capable of segmenting low contrasted airway regions. Our segmentation using projections method shows robustness in images with high presence of noise.
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Affiliation(s)
- Danilo Babin
- Department of Telecommunications and Information Processing-TELIN-IPI-IBBT, Faculty of Sciences, Ghent University, Sint-Pietersnieuwstraat 41, B-9000, Belgium.
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Babin D, Vansteenkiste E, Pizurica A, Philips W. Segmentation and length measurement of the abdominal blood vessels in 3-D MRI images. Annu Int Conf IEEE Eng Med Biol Soc 2009; 2009:4399-4402. [PMID: 19964361 DOI: 10.1109/iembs.2009.5333689] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
In diagnosing diseases and planning surgeries the structure and length of blood vessels is of great importance. In this research we develop a novel method for the segmentation of 2-D and 3-D images with an application to blood vessel length measurements in 3-D abdominal MRI images. Our approach is robust to noise and does not require contrast-enhanced images for segmentation. We use an effective algorithm for skeletonization, graph construction and shortest path estimation to measure the length of blood vessels of interest.
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Affiliation(s)
- Danilo Babin
- Department of Telecommunications and Information Processing-TELIN-IPI-IBBT, Faculty of Sciences, Ghent University, Sint-Pietersnieuwstraat 41, B-9000 Ghent, Belgium.
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Loreau M, Oteng-Yeboah A, Arroyo MTK, Babin D, Barbault R, Donoghue M, Gadgil M, Häuser C, Heip C, Larigauderie A, Ma K, Mace G, Mooney HA, Perrings C, Raven P, Sarukhan J, Schei P, Scholes RJ, Watson RT. Diversity without representation. Nature 2006; 442:245-6. [PMID: 16855567 DOI: 10.1038/442245a] [Citation(s) in RCA: 112] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Michel Loreau
- Department of Biology, McGill University, Montreal, Quebec H3A 1B1, Canada
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Hemmerling TM, Babin D. Phonomyography--acoustic myography using condenser microphones: a promising new method of monitoring neuromuscular transmission. Anaesth Intensive Care 2002; 30:532-3. [PMID: 12180599] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/26/2023]
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Hemmerling TM, Donati F, Beaulieu P, Babin D. Phonomyography of the corrugator supercilii muscle: signal characteristics, best recording site and comparison with acceleromyography. Br J Anaesth 2002; 88:389-93. [PMID: 11990272 DOI: 10.1093/bja/88.3.389] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND This study investigated the acoustic signal characteristics and best recording site of phonomyography at the corrugator supercilii muscle and compared phonomyography with acceleromyography. METHODS In 12 patients (group I), after induction of anaesthesia and insertion of a laryngeal mask, a microphone (frequency range 2.5 Hz to 10 kHz) was placed on six different areas on the forehead and the peak-to-peak response after single-twitch stimulation of the facial nerve was measured. The microphone was placed where the response was largest and mivacurium 0.2 mg kg(-1) was administered. Fast Fourier transformation was applied to all signals to determine peak frequencies and the power-frequency relationship at different stages of neuromuscular block. In an additional 15 patients (group II), the same microphone and an acceleromyographic probe were placed above the middle portion of the left and right eyebrows respectively. Onset and offset of neuromuscular block were determined after mivacurium 0.2 mg kg(-1). RESULTS In all seven women and all five men in group I, the best response was obtained just above the middle portion of the eyebrow. Peak frequency was 4.1 (SD 0.9) Hz without neuromuscular block and did not change significantly during onset and offset of neuromuscular block. Ninety per cent of the total signal power was below 40 Hz. In group II, mean onset time and maximum effect measured were 104 (20) s and 76 (10)% respectively using acceleromyography and 134 (30) s and 92 (4)% using phonomyography (P<0.04). Mean time to reach 25, 75 and 90% of control was 9.5 (2.8), 14 (5.1) and 15.1 (5.3) min respectively using acceleromyography and 6.9 (2.8), 12.5 (5.9) and 13.6 (4.9) min using phonomyography (P<0.04). Bland-Altman testing revealed significant bias (precision) for onset time, maximum effect and time to reach 25% of control (acceleromyography minus phonomyography) at -30 (38) s, -16 (11)% and 2.6 (2.8) min respectively. CONCLUSIONS Phonomyography can be used to determine neuromuscular block at the corrugator supercilii muscle. In comparison with acceleromyography, phonomyography tends to measure a longer onset with more pronounced maximum effect and shorter recovery of neuromuscular block.
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Affiliation(s)
- T M Hemmerling
- Department of Anaesthesia, Centre Hospitalier de l'Université de Montréal, Québec, Canada
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Haché M, Denault AY, Bélisle S, Couture P, Babin D, Tétrault F, Guimond JG. Inhaled prostacyclin (PGI2) is an effective addition to the treatment of pulmonary hypertension and hypoxia in the operating room and intensive care unit. Can J Anaesth 2001; 48:924-9. [PMID: 11606352 DOI: 10.1007/bf03017361] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
PURPOSE There is a growing interest in the intraoperative and intensive care use of inhaled epoprostenol (PGI2) for the treatment of pulmonary hypertension (PHT) and hypoxia of cardiac or non-cardiac origin. We report our experience with this form of therapy. METHODS A retrospective chart review of all patients who received inhaled PGI2 over a one-year period was undertaken. Demographic, hemodynamic, oxygenation status, mode of administration, side effects, duration of hospital stay, and mortality were noted. RESULTS Thirty-five patients, of which 33 (92%) were in the intensive care unit, received inhaled PGI2. Of the 27 patients whose pulmonary artery pressure (PAP) was monitored, a significant decrease in mean PAP from 34.8 +/- 11.8 mmHg to 32.1 +/- 11.8 mmHg was observed within one hour after the start of therapy (P=0.0017). Selective pulmonary vasodilatation occurred in 77.8% of the patients. Thirty-three patients had arterial blood gases before and after therapy. There was an improvement in the PaO2/FIO2 ratio in 88% of these with a 175% improvement on average. The ratio of PaO2/FIO2 improved from 108 +/- 8 to 138 +/- 105 (P=0.001). Six patients (17%) presented hypotension, two had subsequent pneumothorax, one had bronchospasm and in one patient PGI2 inhalation was stopped because of increasing peak pulmonary pressures from the secondary flow coming from the nebulizer. Mortality of the cohort was 54%. CONCLUSION Inhaled PGI2 can be useful in the treatment of patients with PHT and severe hypoxia. It can however be associated with systemic side effects.
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Affiliation(s)
- M Haché
- Department of Anesthesiology, Montreal Heart Institute, Centre Hospitalier de l'Université de Montréal, Campus Notre-Dame, Montreal, Quebec, Canada
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Bernard F, Denault A, Babin D, Goyer C, Couture P, Couturier A, Buithieu J. Diastolic dysfunction is predictive of difficult weaning from cardiopulmonary bypass. Anesth Analg 2001. [PMID: 11159219 DOI: 10.1213/00000539-200102000-00002] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Diastolic function is receiving more attention since echocardiographic measurements were developed and have become widely available. The importance and significance of diastolic dysfunction (DD) observed before cardiac surgery and its relationship with adverse outcomes, such as difficult separation from cardiopulmonary bypass (CPB), have not been fully explored. In this study, we hypothesize that DD can be a predictor for the need of inotropic support to successfully separate from CPB. Ninety-two consecutive patients underwent surgery during the study period. Twenty-six patients were excluded. From the remaining 66 patients, 52 had coronary artery bypass grafting alone and 14 combined procedures, valvular surgery, and reoperations (redo). Systolic and diastolic function was evaluated by two experts blinded as to the clinical data except for the age. The evaluation of diastolic function was done according to published guidelines. The demographic, echocardiographic, and hemodynamic variables were entered in a logistic regression analysis to determine which variables were independent predictors of difficult separation from CPB and the need for postoperative vasoactive support. DD was present in 20 patients (30%). Patients with DD had lower weight (P = 0.046), less frequent coronary artery bypass grafting alone (P = 0.0004), more myocardial infarction before surgery (P = 0.02), higher regional wall motion score index (P = 0.0002), and larger left ventricle (P = 0.03). Total CPB time (P = 0.004) and ischemic time (P = 0.007) were longer in the DD group. Patients with DD required more frequent inotropic support at the end of surgery (P = 0.006) and up to 12 h after surgery (P = 0.003). Multivariate logistic regression identified female sex, DD, and total CPB time as predictive of difficult weaning and inotropic requirements up to 12 h after surgery.
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Affiliation(s)
- F Bernard
- Department of Medicine, CHUM, Notre-Dame Hospital, Montreal, Quebec, Canada
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Abstract
PURPOSE Veno-arterial and regional differences of the partial pressure in CO2 (deltaPCO2), may be used as index to evaluate the adequacy of the cardiac output to the oxygen consumption. To determine the incidence of elevated deltaPCO2 and its relationship with difficult separation from bypass (DSB) in patients undergoing cardiac surgery, we conducted a prospective observational cohort study. METHODS Data were collected from 58 consecutive patients undergoing various cardiac operations requiring cardiopulmonary bypass (CPB). During the procedure, arterial and venous blood gases and lactate were sampled. Blood was drawn after induction of anesthesia, during bypass and at the closure of the chest wall. Difficult separation from bypass was defined as a systolic arterial pressure < 80 mmHg, and diastolic pulmonary artery pressure > 15 mmHg during progressive separation from CPB with inotropic or mechanical support of cardiac function, or hemodynamic instability resulting in reintroduction of extra-corporeal circulation or insertion of an intra-aortic balloon pump. RESULTS In our study, 65% of the samples were associated with elevated deltaPCO2 (> 6 mmHg). Variables associated with difficult weaning were LVEF; duration of bypass and aortic cross-clamping, pre-bypass deltaPCO2 and in-bypass lactate values (P < 0.05). Multivariable analysis identified the pre-bypass deltaPCO2 and the duration of bypass as predictors of DSB. CONCLUSION Elevated deltaPCO2 is frequently observed during cardiac surgery and values obtained before bypass were associated with DSB. The deltaPCO2 gradients could be used as marker of the adequacy of tissue perfusion during cardiac surgery.
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Affiliation(s)
- A Denault
- Department of Anesthesiology, Research Center, Montreal Heart Institute, Quebec, Canada.
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Bernard F, Denault A, Babin D, Goyer C, Couture P, Couturier A, Buithieu J. Diastolic dysfunction is predictive of difficult weaning from cardiopulmonary bypass. Anesth Analg 2001; 92:291-8. [PMID: 11159219 DOI: 10.1097/00000539-200102000-00002] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Diastolic function is receiving more attention since echocardiographic measurements were developed and have become widely available. The importance and significance of diastolic dysfunction (DD) observed before cardiac surgery and its relationship with adverse outcomes, such as difficult separation from cardiopulmonary bypass (CPB), have not been fully explored. In this study, we hypothesize that DD can be a predictor for the need of inotropic support to successfully separate from CPB. Ninety-two consecutive patients underwent surgery during the study period. Twenty-six patients were excluded. From the remaining 66 patients, 52 had coronary artery bypass grafting alone and 14 combined procedures, valvular surgery, and reoperations (redo). Systolic and diastolic function was evaluated by two experts blinded as to the clinical data except for the age. The evaluation of diastolic function was done according to published guidelines. The demographic, echocardiographic, and hemodynamic variables were entered in a logistic regression analysis to determine which variables were independent predictors of difficult separation from CPB and the need for postoperative vasoactive support. DD was present in 20 patients (30%). Patients with DD had lower weight (P = 0.046), less frequent coronary artery bypass grafting alone (P = 0.0004), more myocardial infarction before surgery (P = 0.02), higher regional wall motion score index (P = 0.0002), and larger left ventricle (P = 0.03). Total CPB time (P = 0.004) and ischemic time (P = 0.007) were longer in the DD group. Patients with DD required more frequent inotropic support at the end of surgery (P = 0.006) and up to 12 h after surgery (P = 0.003). Multivariate logistic regression identified female sex, DD, and total CPB time as predictive of difficult weaning and inotropic requirements up to 12 h after surgery.
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Affiliation(s)
- F Bernard
- Department of Medicine, CHUM, Notre-Dame Hospital, Montreal, Quebec, Canada
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Couture P, Denault AY, McKenty S, Boudreault D, Plante F, Perron R, Babin D, Normandin L, Poirier N. Impact of routine use of intraoperative transesophageal echocardiography during cardiac surgery. Can J Anaesth 2000; 47:20-6. [PMID: 10626713 DOI: 10.1007/bf03020726] [Citation(s) in RCA: 87] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
PURPOSE To determine the relative impact of each category-based TEE indication according to the ASA guidelines. METHODS In 851 patients undergoing cardiac surgery, TEE clinical indications were classified as category I or II according to the ASA guidelines. Category I indications are patients in which TEE is considered useful and category II are those where TEE is potentially useful but indications are less clear. All TEE examinations were reviewed by two anesthesiologists with advanced training in TEE. For each patient, the clinical impact of TEE in the clinical management was assessed using five criteria: 1) change of medical therapy; 2) change in the surgical procedure; 3) confirmation of a suspected diagnosis; 4) positioning of an intravascular device, and 5) substitute to a pulmonary artery catheter (PAC). RESULTS TEE had greater utility in category I than in category II indications (15/53 (28%) vs. 110/798 (14%) respectively) (P<0.01). The nature of the clinical impact was as follows: modification of medical therapy in 67/125 (53%), modification of planned surgical intervention in 38/125 (30%), confirmation of a diagnosis in 34/125 (27%). The impact on therapy was higher in complex surgical procedures (39%) than in valvular replacement (19%) (P<0.01) and coronary artery bypass surgery (10%) (P<0.001). CONCLUSIONS Our findings validate the usefulness of the ASA practice guidelines demonstrating a greater impact of TEE on clinical management for category I indications than for category II. TEE also had a greater clinical impact in complex surgical procedures and in valvular replacement.
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Affiliation(s)
- P Couture
- Department of Anesthesiology, Centre Hospitalier de l'Université de Montréal, Québec, Canada.
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Couture P, Denault AY, Carignan S, Boudreault D, Babin D, Ruel M. Intraoperative detection of segmental wall motion abnormalities with transesophageal echocardiography. Can J Anaesth 1999; 46:827-31. [PMID: 10490149 DOI: 10.1007/bf03012970] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
PURPOSE To compare two methods of analysis of regional wall-motion (RWM) using transesophageal echocardiography (TEE). METHODS Thirty patients undergoing coronary artery bypass surgery were studied. The transgastric short axis view at the mid-papillary level was recorded before and after cardiopulmonary bypass. All images were reviewed by an anesthesiologist trained in TEE and an echocardiographer. Regional wall motion was graded: 1 normal, 2 hypokinetic, 3 akinetic, and 4 dyskinetic. The left ventricle was evaluated according to the guidelines of the American Society of Echocardiography using 6-segment, and 4-segment models. Agreement between observers (interobservers), and for one observer at two different moments (intraobservers), for grading each segment was defined as RWM abnormality scores within 1 grade. A wall-motion score index (WMSI), which is the sum of individual scores divided by the number of segments visualized, was calculated. A Bland Altman analysis was used to assess interobserver variability. RESULTS Agreement between observers occurred in 96% and 94% of the examined segments, using 4- and 6-segment models respectively. Intraobserver agreement was 99% and 97% for the 4- and 6-segment models. The mean differences (bias) of the interobserver variability in grading the segments were 0.04 +/- 0.79 and 0 +/- 0.72 using a 4- or 6-segment model. The mean difference of the interobserver variability in WMSI were -0.05 +/- 0.42 and 0.05 +/- 0.37 using a 4- or a 6-segment model. CONCLUSION Both methods, using either a 4- or a 6-segment model, result in a high intraobserver and interobserver agreement, and a low interobserver variability.
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Affiliation(s)
- P Couture
- Department of Anesthesia, Montreal Heart Institute, Quebec, Canada.
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Trainer VL, McPhee JC, Boutelet-Bochan H, Baker C, Scheuer T, Babin D, Demoute JP, Guedin D, Catterall WA. High affinity binding of pyrethroids to the alpha subunit of brain sodium channels. Mol Pharmacol 1997; 51:651-7. [PMID: 9106631 DOI: 10.1124/mol.51.4.651] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Na+ channels are the primary molecular targets of the pyrethroid insecticides. Na+ channels consisting of only a type IIA alpha subunit expressed in Chinese hamster ovary cells responded to pyrethroid treatment in a normal manner: a sustained Na+ current was induced progressively after each depolarizing pulse in a train of stimuli, and this Na+ current decayed slowly on repolarization. These modified Na+ channels could be reactivated at much more negative membrane potentials (V0.5 = -139 mV) than unmodified Na+ channels (V0.5 = -28 mV). These results indicate that pyrethroids can modify the functional properties of the Na+ channel alpha subunit expressed alone by blocking their inactivation, shifting their voltage dependence of activation, and slowing their deactivation. To demonstrate directly the specific interaction of pyrethroids with the alpha subunit of voltage-gated Na+ channels, a radioactive photosensitive derivative, [3H]RU58487, was used in binding and photolabeling studies. In the presence of a low concentration of the nonionic detergent Triton X-100, specific pyrethroid binding to Na+ channels in rat brain membrane preparations could be measured and reached 75% of total binding under optimal conditions. Binding approached equilibrium within 1 hr at 4 degrees, dissociated with a half-time of approximately 10 min, and had K(D) values of approximately 58-300 nM for three representative pyrethroids. Specific pyrethroid binding was enhanced by approximately 40% in the presence of 100 nM alpha-scorpion toxin, but no allosteric enhancement was observed in the presence of toxins acting at other Na+ channel receptor sites. Extensive membrane washing increased specific binding to 89%. Photolabeling with [3H]RU58487 under these optimal binding conditions revealed a radiolabeled band with an apparent molecular mass of 240 kDa corresponding to the Na+ channel alpha subunit. Anti-peptide antibodies recognizing sequences within the alpha subunit were able to specifically immunoprecipitate the covalently modified channel. Together, these results demonstrate that the pyrethroids can modify the properties of cells expressing only the alpha subunit of Na+ channels and can bind specifically to a receptor site on the alpha subunit.
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Affiliation(s)
- V L Trainer
- Department of Pharmacology, University of Washington, Seattle 98195, USA
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Prioreschi P, Babin D. [Kos and Knidos]. Hist Sci Med 1995; 29:317-24. [PMID: 11625931] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/17/2023]
Abstract
The authors review the evidence concerning the antagonism between Cos and Cnidus and the alleged differences between their medical theories. They conclude that, most probably, the theoretical differences were negligible and the antagonism limited to professional competition between two groups of physicians sharing a common medical paradigm.
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Affiliation(s)
- P Prioreschi
- Creighton University, Omaha, Nebraska 68178, USA
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Abstract
Recent investigation from this laboratory has identified in the rat brain a zinc-inducible and actinomycin D-inhibited metallothionein with an elution volume (Ve/Vo) of 2.08 and a molecular weight of smaller than 10,000 daltons. Furthermore, purification of the zinc-induced metallothionein by ion exchange chromatography on DEAE-Sephadex A-25 columns produced two isoforms, eluting, respectively, at 68 and 130 mM of Tris-acetate buffer, pH 7.5. In this paper, we report that zinc-induced metallothionein produces also two distinct isoforms on reverse phase high performance liquid chromatography that exhibit retention times of 17.23 and 18.53 minutes, respectively. Brain metallothionein was characterized further by studies showing that the zinc-induced metallothionein incorporated a large quantity of [35S]cysteine and that isoforms I and II contain 17 and 18 cysteine residues, respectively, while being devoid of any arginine, histidine, leucine, phenylalanine or tyrosine. The precise functions of the brain metallothionein isoforms, which may be related to the transport and homeostasis of essential elements such as zinc and copper, remain to be elucidated.
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Affiliation(s)
- M Ebadi
- Department of Pharmacology, University of Nebraska College of Medicine, Omaha 68105
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Abstract
Two new allergenic specificites were detected in honeybee venom and the two corresponding protein substances isolated by gel filtration, immunoadsorption, and ion exchange chromatography. The first of these, allergen B, has a molecular weight ranging from 49,000 to more than 200,00 d and can be recognized by rabbit and guinea pig antisera as well as by human reaginic sera using the radioallergosorbent test (RAST). Allergen B gives a single line in immunodiffusion distinct from hyaluronidase, phospholipase A, melittin, and the other high molecular weight substances described and gives a single band at 49,000 d in sodium dodecyl sulfate (SDS) polyacrylamide gel. The second substance, allergen C, has a molecular weight of 105,000 d and was separated from allergen B by immunoadsorption with insoluble antibody. Allergen C was shown to be distinct from the other sustances in bee venom by immunodiffusion with animal antisera. One human reaginic serum was monospecific for allergen C. Two other minor components of 86,000 and 71,000 d are present in bee venom; their allergenic activities are unknown. The two specifities, B and C, comprise most of the reactivity of the previously described Sephadex G-75 fraction 1 and clearly are important allergens, reacting with 98% of sera from bee venom-allergic individuals.
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