Svetla Boytcheva

Dr. Svetla Boytcheva


Research Focus & Metrics

Academic Career Length

27Years (2000-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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22 July 2022 in npj Digital Medicine
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Journal Article
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NMNiccolo Marini
Niccolo Marini
SMStefano Marchesin
Stefano Marchesin
SOSebastian Otálora
Sebastian Otálora
MWMarek Wodzinski
Marek Wodzinski
ACAlessandro Caputo
Alessandro Caputo
Manfredo AtzoriManfredo Atzori
Manfredo Atzori
The digitalization of clinical workflows and the increasing performance of deep learning algorithms are paving the way towards new methods for tackling cancer diagnosis. However, the availability of medical specialists to annotate digitized images and free-text diagnostic reports does not scale with the need for large datasets required to train robust computer-aided diagnosis methods that can target the high variability of clinical cases and data produced. This work proposes and evaluates an approach to eliminate the need for manual annotations to train computer-aided diagnosis tools in digital pathology. The approach includes two components, to automatically extract semantically meaningful concepts from diagnostic reports and use them as weak labels to train convolutional neural networks (CNNs) for histopathology diagnosis. The approach is trained (through 10-fold cross-validation) on 3’769 clinical images and reports, provided by two hospitals and tested on over 11’000 images from private and publicly available datasets. The CNN, trained with automatically generated labels, is compared with the same architecture trained with manual labels. Results show that combining text analysis and end-to-end deep neural networks allows building computer-aided diagnosis tools that reach solid performance (micro-accuracy = 0.908 at image-level) based only on existing clinical data without the need for manual annotations.

11 June 2020 in Information
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Journal Article
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PBPavel Boytchev
Pavel Boytchev
SBSvetla Boytcheva
Svetla Boytcheva
The process of converting non-game educational content and processes into game-like educational content and processes is called gamification. This article describes a gamified evaluation software for university students in Science, Technology, Engineering, the Arts and Mathematics (STEAM) courses, based on competence profiles of students and problems. The traditional learning management systems and learning tools cannot handle gamification to its full potential because of the unique requirements of gamified environments. We designed a novel gamification evaluation and assessment methodology implemented in a STEAM course through specially designed software. The results from end-user tests show a positive expectation of students’ performance and motivation. The preliminary results of over 100 students in the Fundamentals of Computer Graphics course are presented and the results of quantitative analysis are discussed. In addition we present an analysis of students’ surveys, where students expressed in free text form observations about the software.

14 August 2024 in Medical Image Analysis
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Journal Article
Open access
NMNiccolo Marini
Niccolo Marini
SMStefano Marchesin
Stefano Marchesin
MWMarek Wodzinski
Marek Wodzinski
Alessandro CaputoAlessandro Caputo
Alessandro Caputo
DPDamian Podareanu
Damian Podareanu
Manfredo AtzoriManfredo Atzori
Manfredo Atzori
The increasing availability of biomedical data creates valuable resources for developing new deep learning algorithms to support experts, especially in domains where collecting large volumes of annotated data is not trivial. Biomedical data include several modalities containing complementary information, such as medical images and reports: images are often large and encode low-level information, while reports include a summarized high-level description of the findings identified within data and often only concerning a small part of the image. However, only a few methods allow to effectively link the visual content of images with the textual content of reports, preventing medical specialists from properly benefitting from the recent opportunities offered by deep learning models. This paper introduces a multimodal architecture creating a robust biomedical data representation encoding fine-grained text representations within image embeddings. The architecture aims to tackle data scarcity (combining supervised and self-supervised learning) and to create multimodal biomedical ontologies. The architecture is trained on over 6,000 colon whole slide Images (WSI), paired with the corresponding report, collected from two digital pathology workflows. The evaluation of the multimodal architecture involves three tasks: WSI classification (on data from pathology workflow and from public repositories), multimodal data retrieval, and linking between textual and visual concepts. Noticeably, the latter two tasks are available by architectural design without further training, showing that the multimodal architecture that can be adopted as a backbone to solve peculiar tasks. The multimodal data representation outperforms the unimodal one on the classification of colon WSIs and allows to halve the data needed to reach accurate performance, reducing the computational power required and thus the carbon footprint. The combination of images and reports exploiting self-supervised algorithms allows to mine databases without needing new annotations provided by experts, extracting new information. In particular, the multimodal visual ontology, linking semantic concepts to images, may pave the way to advancements in medicine and biomedical analysis domains, not limited to histopathology.

28 September 2017 in Health Information Science and Systems
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Journal Article
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SBSvetla Boytcheva
Svetla Boytcheva
Galia AngelovaGalia Angelova
Galia Angelova
ZAZhivko Angelov
Zhivko Angelov
DTDimitar Tcharaktchiev
Dimitar Tcharaktchiev
Background: Studying comorbidities of disorders is important for detection and prevention. For discovering frequent patterns of diseases we can use retrospective analysis of population data, by filtering events with common properties and similar significance. Most frequent pattern mining methods do not consider contextual information about extracted patterns. Further data mining developments might enable more efficient applications in specific tasks like comorbidities identification.Methods: We propose a cascade data mining approach for frequent pattern mining enriched with context information, including a new algorithm MIxCO for maximal frequent patterns mining. Text mining tools extract entities from free text and deliver additional context attributes beyond the structured information about the patients.Results: The proposed approach was tested using pseudonymised reimbursement requests (outpatient records) submitted to the Bulgarian National Health Insurance Fund in 2010–2016 for more than 5 million citizens yearly. Experiments were run on 3 data collections. Some known comorbidities of Schizophrenia, Hyperprolactinemia and Diabetes Mellitus Type 2 are confirmed; novel hypotheses about stable comorbidities are generated. The evaluation shows that MIxCO is efficient for big dense datasets.Conclusion: Explicating maximal frequent itemsets enables to build hypotheses concerning the relationships between the exogeneous and endogeneous factors triggering the formation of these sets. MixCO will help to identify risk groups of patients with a predisposition to develop socially-significant disorders like diabetes. This will turn static archives like the Diabetes Register in Bulgaria to a powerful alerting and predictive framework.

1 November 2015 in Cybernetics and Information Technologies
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Journal Article
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SBSvetla Boytcheva
Svetla Boytcheva
Galia AngelovaGalia Angelova
Galia Angelova
ZAZhivko Angelov
Zhivko Angelov
DTDimitar Tcharaktchiev
Dimitar Tcharaktchiev
This paper presents the results of an on-going research project for knowledge extraction from large corpora of clinical narratives in Bulgarian language, approximately 100 million of outpatient care notes. Entities with numerical values are mined in the free text and the extracted information is stored in a structured format. The Algorithms for retrospective analyses and big data analytics are applied for studying the treatment and evaluating the diabetes compensation and control of arterial blood pressure.

1 January 2003
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Conference Paper
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MYMilena Yankova
Milena Yankova
SBSvetla Boytcheva
Svetla Boytcheva