Ioannis Karatzanis

Mr. Ioannis Karatzanis

orcid

Research Focus & Metrics

Academic Career Length

12Years (2015-Present)

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

Representative Publications

View All Publications
17 March 2021 in IEEE Reviews in Biomedical Engineering
Verified
Journal Article
Closed access
VSVasileios Skaramagkas
Vasileios Skaramagkas
Giorgos GiannakakisGiorgos Giannakakis
Giorgos Giannakakis
EKEmmanouil Ktistakis
Emmanouil Ktistakis
DMDimitris Manousos
Dimitris Manousos
IKIoannis Karatzanis
Ioannis Karatzanis
Manolis TsiknakisManolis Tsiknakis
Manolis Tsiknakis
Eye behaviour provides valuable information revealing one's higher cognitive functions and state of affect. Although eye tracking is gaining ground in the research community, it is not yet a popular approach for the detection of emotional and cognitive states. In this paper, we present a review of eye and pupil tracking related metrics (such as gaze, fixations, saccades, blinks, pupil size variation, etc.) utilized towards the detection of emotional and cognitive processes, focusing on visual attention, emotional arousal and cognitive workload. Besides, we investigate their involvement as well as the computational recognition methods employed for the reliable emotional and cognitive assessment. The publicly available datasets employed in relevant research efforts were collected and their specifications and other pertinent details are described. The multimodal approaches which combine eye-tracking features with other modalities (e.g. biosignals), along with artificial intelligence and machine learning techniques were also surveyed in terms of their recognition/classification accuracy. The limitations, current open research problems and prospective future research directions were discussed for the usage of eye-tracking as the primary sensor modality. This study aims to comprehensively present the most robust and significant eye/pupil metrics based on available literature towards the development of a robust emotional or cognitive computational model.

Verified
Journal Article
Open access
PDF file
EKEleni Kolokotroni
Eleni Kolokotroni
DADaniel Abler
Daniel Abler
AGAlokendra Ghosh
Alokendra Ghosh
ETEleftheria Tzamali
Eleftheria Tzamali
JGJames Grogan
James Grogan
GSGeorgios S. Stamatakos
Georgios S. Stamatakos
The massive amount of human biological, imaging, and clinical data produced by multiple and diverse sources necessitates integrative modeling approaches able to summarize all this information into answers to specific clinical questions. In this paper, we present a hypermodeling scheme able to combine models of diverse cancer aspects regardless of their underlying method or scale. Describing tissue-scale cancer cell proliferation, biomechanical tumor growth, nutrient transport, genomic-scale aberrant cancer cell metabolism, and cell-signaling pathways that regulate the cellular response to therapy, the hypermodel integrates mutation, miRNA expression, imaging, and clinical data. The constituting hypomodels, as well as their orchestration and links, are described. Two specific cancer types, Wilms tumor (nephroblastoma) and non-small cell lung cancer, are addressed as proof-of-concept study cases. Personalized simulations of the actual anatomy of a patient have been conducted. The hypermodel has also been applied to predict tumor control after radiotherapy and the relationship between tumor proliferative activity and response to neoadjuvant chemotherapy. Our innovative hypermodel holds promise as a digital twin-based clinical decision support system and as the core of future in silico trial platforms, although additional retrospective adaptation and validation are necessary.

1 September 2023 in JCO Clinical Cancer Informatics
Verified
Journal Article
Closed access
VKVarvara Kalokyri
Varvara Kalokyri
Haridimos KondylakisHaridimos Kondylakis
Haridimos Kondylakis
SSStelios Sfakianakis
Stelios Sfakianakis
KNKATERINA NIKIFORAKI
KATERINA NIKIFORAKI
IKIoannis Karatzanis
Ioannis Karatzanis
Manolis TsiknakisManolis Tsiknakis
Manolis Tsiknakis
PURPOSE: The explosion of big data and artificial intelligence has rapidly increased the need for integrated, homogenized, and harmonized health data. Many common data models (CDMs) and standard vocabularies have appeared in an attempt to offer harmonized access to the available information, with Observational Medical Outcomes Partnership (OMOP)-CDM being one of the most prominent ones, allowing the standardization and harmonization of health care information. However, despite its flexibility, still capturing imaging metadata along with the corresponding clinical data continues to pose a challenge. This challenge arises from the absence of a comprehensive standard representation for image-related information and subsequent image curation processes and their interlinkage with the respective clinical information. Successful resolution of this challenge holds the potential to enable imaging and clinical data to become harmonized, quality-checked, annotated, and ready to be used in conjunction, in the development of artificial intelligence models and other data-dependent use cases. METHODS: To address this challenge, we introduce medical imaging (MI)-CDM—an extension of the OMOP-CDM specifically designed for registering medical imaging data and curation-related processes. Our modeling choices were the result of iterative numerous discussions among clinical and AI experts to enable the integration of imaging and clinical data in the context of the ProCAncer-I project, for answering a set of clinical questions across the prostate cancer's continuum. RESULTS: Our MI-CDM extension has been successfully implemented for the use case of prostate cancer for integrating imaging and curation metadata along with clinical information by using the OMOP-CDM and its oncology extension. CONCLUSION: By using our proposed terminologies and standardized attributes, we demonstrate how diverse imaging modalities can be seamlessly integrated in the future.

9 May 2024 in Journal of Imaging
Verified
Journal Article
Open access
PDF file
KNKaterina Nikiforaki
Katerina Nikiforaki
IKIoannis Karatzanis
Ioannis Karatzanis
ADAikaterini Dovrou
Aikaterini Dovrou
MBMaciej Bobowicz
Maciej Bobowicz
KGKatarzyna Gwozdziewicz
Katarzyna Gwozdziewicz
Kostas MariasKostas Marias
Kostas Marias
Image quality assessment of magnetic resonance imaging (MRI) data is an important factor not only for conventional diagnosis and protocol optimization but also for fairness, trustworthiness, and robustness of artificial intelligence (AI) applications, especially on large heterogeneous datasets. Information on image quality in multi-centric studies is important to complement the contribution profile from each data node along with quantity information, especially when large variability is expected, and certain acceptance criteria apply. The main goal of this work was to present a tool enabling users to assess image quality based on both subjective criteria as well as objective image quality metrics used to support the decision on image quality based on evidence. The evaluation can be performed on both conventional and dynamic MRI acquisition protocols, while the latter is also checked longitudinally across dynamic series. The assessment provides an overall image quality score and information on the types of artifacts and degrading factors as well as a number of objective metrics for automated evaluation across series (BRISQUE score, Total Variation, PSNR, SSIM, FSIM, MS-SSIM). Moreover, the user can define specific regions of interest (ROIs) to calculate the regional signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR), thus individualizing the quality output to specific use cases, such as tissue-specific contrast or regional noise quantification.

8 March 2024 in Preprints.org
Verified
Preprint
Open access
PDF file
EKEleni Kolokotroni
Eleni Kolokotroni
DADaniel Abler
Daniel Abler
AGAlokendra Ghosh
Alokendra Ghosh
ETEleftheria Tzamali
Eleftheria Tzamali
JGJames Grogan
James Grogan
GSGeorgios S. Stamatakos
Georgios S. Stamatakos
The massive amount of human biological, imaging and clinical data produced by multiple and diverse sources, necessitates integrative modeling approaches able to summarize all this information into answers to specific clinical questions. In this paper, we present a hypermodeling scheme able to combine models of diverse cancer aspects regardless of their underlying method or scale. Describing tissue-scale cancer cell proliferation, biomechanical tumor growth, nutrient transport, genomic-scale aberrant cancer cell metabolism, and cell signaling pathways that regulate the cellular response to therapy, the hypermodel integrates mutation, miRNA expression, imaging, and clinical data. The constituting hypomodels as well as their orchestration and links are described. Two specific cancer types, Wilms tumor (nephroblastoma) and non-small cell lung cancer, are addressed as proof of concept study cases. Personalized simulations over the actual anatomy of a patient have been carried out. The hypermodel has also applied to predict tumor control after radiotherapy and the relationship between tumor proliferative activity and response to neoadjuvant chemotherapy. Our innovative hypermodel holds promise as a digital twin based clinical decision support system and the core of future in silico trial platforms, although additional retrospective adaptation and validation is necessary.

1 January 2015 in Journal of Clinical Bioinformatics
Verified
Journal Article
Open access
PDF file
IKIoannis Karatzanis
Ioannis Karatzanis
Kostas MariasKostas Marias
Kostas Marias
VSVangelis Sakkalis
Vangelis Sakkalis