Publications by authors named "Paragios N"

: To evaluate an end-to-end pipeline for normo-fractionated prostate-only and whole-pelvic cancer treatments that requires minimal human input and generates a machine-deliverable plan as an output. : In collaboration with TheraPanacea, a treatment planning pipeline was developed that takes as its input a planning CT with organs-at-risk (OARs) and planning target volume (PTV) contours, the targeted linac machine, and the prescription dose. The primary components are (i) dose prediction by a single deep learning model for both localizations and (ii) a direct aperture VMAT plan optimization that seeks to mimic the predicted dose.

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Challenges drive the state-of-the-art of automated medical image analysis. The quantity of public training data that they provide can limit the performance of their solutions. Public access to the training methodology for these solutions remains absent.

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Ionizing radiation can have a wide range of impacts on tumor-immune interactions, which are being studied with the greatest interest and at an accelerating pace by the medical community. Despite its undeniable immunostimulatory potential, it clearly appears that radiotherapy as it is prescribed and delivered nowadays often alters the host's immunity toward a suboptimal state. This may impair the full recovery of a sustained and efficient antitumor immunosurveillance posttreatment.

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Background: Radiotherapy dose predictions have been trained with data from previously treated patients of similar sites and prescriptions. However, clinical datasets are often inconsistent and do not contain the same number of organ at risk (OAR) structures. The effects of missing contour data in deep learning-based dose prediction models have not been studied.

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Purpose/objectives: An artificial intelligence-based pseudo-CT from low-field MR images is proposed and clinically evaluated to unlock the full potential of MRI-guided adaptive radiotherapy for pelvic cancer care.

Materials And Method: In collaboration with TheraPanacea (TheraPanacea, Paris, France) a pseudo-CT AI-model was generated using end-to-end ensembled self-supervised GANs endowed with cycle consistency using data from 350 pairs of weakly aligned data of pelvis planning CTs and TrueFisp-(0.35T)MRIs.

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The use of multi-modality imaging technologies such as CT, MRI, and PET imaging is state of the art for radiation therapy treatment planning. Except for a limited number of low magnetic field MR scanners the majority of such imaging technologies can only image the patient in a recumbent position. Delivering radiation therapy treatments with the patient in an upright orientation has many benefits and several companies are now developing upright patient positioners combined with upright diagnostic helical CT scanners to facilitate upright radiation therapy treatments.

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Background And Purpose: MR-guided radiotherapy (MRgRT) online plan adaptation accounts for tumor volume changes, interfraction motion and thus allows daily sparing of relevant organs at risk. Due to the high interfraction variability of bladder and rectum, patients with tumors in the pelvic region may strongly benefit from adaptive MRgRT. Currently, fast automatic annotation of anatomical structures is not available within the online MRgRT workflow.

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Multiple sclerosis (MS) is a chronic inflammatory and neurodegenerative disease characterized by the appearance of focal lesions across the central nervous system. The discrimination of acute from chronic MS lesions may yield novel biomarkers of inflammatory disease activity which may support patient management in the clinical setting and provide endpoints in clinical trials. On a single timepoint and in the absence of a prior reference scan, existing methods for acute lesion detection rely on the segmentation of hyperintense foci on post-gadolinium T1-weighted magnetic resonance imaging (MRI), which may underestimate recent acute lesion activity.

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While radiomics analysis has been applied for localized cancer disease, its application to the metastatic setting involves a non-exhaustive lesion subsampling strategy which may sidestep the intrapatient tumoral heterogeneity, hindering the reproducibility and the therapeutic response performance. Our aim was to evaluate if radiomics features can capture intertumoral intrapatient heterogeneity, and the impact of tumor subsampling on the computed heterogeneity. To this end, We delineated and extracted radiomics features of all visible tumors from single acquisition pre-treatment computed tomography of patients with metastatic lung cancer (cohort L) and confirmed our results on a larger cohort of patients with metastatic melanoma (cohort M).

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The Apparent Diffusion Coefficient (ADC) is considered an importantimaging biomarker contributing to the assessment of tissue microstructure and pathophy- siology. It is calculated from Diffusion-Weighted Magnetic Resonance Imaging (DWI) by means of a diffusion model, usually without considering any motion during image acquisition. We propose a method to improve the computation of the ADC by coping jointly with both motion artifacts in whole-body DWI (through group-wise registration) and possible instrumental noise in the diffusion model.

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Article Synopsis
  • Precision medicine is evolving through genomics, but challenges like complex biological interactions and data analysis hinder its clinical use.
  • This paper proposes a new unsupervised framework using the LP-Stability algorithm to identify low-dimensional gene biomarkers, enhancing flexibility and scalability in identifying clusters.
  • The proposed method outperforms existing clustering techniques, showing significant improvements in mathematical and biological metrics, and effectively classifies tumor types and subtypes with high accuracy rates.
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Purpose: The purpose of this study was to determine whether a single reconstruction kernel or both high and low frequency kernels should be used for training deep learning models for the segmentation of diffuse lung disease on chest computed tomography (CT).

Materials And Methods: Two annotated datasets of COVID-19 pneumonia (323,960 slices) and interstitial lung disease (ILD) (4,284 slices) were used. Annotated CT images were used to train a U-Net architecture to segment disease.

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Purpose: To develop a deep learning algorithm for the automatic assessment of the extent of systemic sclerosis (SSc)-related interstitial lung disease (ILD) on chest CT images.

Materials And Methods: This retrospective study included 208 patients with SSc (median age, 57 years; 167 women) evaluated between January 2009 and October 2017. A multicomponent deep neural network (AtlasNet) was trained on 6888 fully annotated CT images (80% for training and 20% for validation) from 17 patients with no, mild, or severe lung disease.

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Purpose: To develop radiomics-based CT scores for assessing lung disease severity and exacerbation risk in adult patients with cystic fibrosis (CF).

Materials And Methods: This two-center retrospective observational study was approved by an institutional ethics committee, and the need for patient consent was waived. A total of 215 outpatients with CF referred for unenhanced follow-up chest CT were evaluated in two different centers between January 2013 and December 2016.

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We investigate the use of recent advances in deep learning and propose an end-to-end trainable multi-instance convolutional neural network within a mixture-of-experts formulation that combines information from two types of data-images and clinical attributes-for the diagnosis of lymphocytosis. The convolutional network learns to extract meaningful features from images of blood cells using an embedding level approach and aggregates them. Moreover, the mixture-of-experts model combines information from these images as well as clinical attributes to form an end-to-end trainable pipeline for diagnosis of lymphocytosis.

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Article Synopsis
  • The study investigates the potential benefits of combining radiotherapy with immuno-oncology therapy in cancer treatment and evaluates a CD8 T-cell radiomics signature for predicting patient outcomes and tumor response.* -
  • It analyzes data from 94 patients with advanced solid tumors, focusing on both irradiated and non-irradiated lesions, assessing their response to IORT and the impact of tumor heterogeneity.* -
  • Results indicate that higher baseline CD8 radiomics scores correlate with better tumor response and that the distribution of these scores is linked to factors such as progression-free survival and overall treatment outcomes.*
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Article Synopsis
  • COVID-19, which surfaced in 2019, spread quickly around the globe, and CT imaging is crucial for screening, quantifying, and staging the disease.
  • Effective staging is necessary for healthcare management, such as planning for ICU beds and enhancing drug development through quick assessments.
  • This study explored the use of medical imaging and AI to improve disease quantification and patient outcomes, demonstrating promising results through automated deep learning methods and combining imaging data with clinical information.
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Background Longitudinal follow-up of interstitial lung diseases (ILDs) at CT mainly relies on the evaluation of the extent of ILD, without accounting for lung shrinkage. Purpose To develop a deep learning-based method to depict worsening of ILD based on lung shrinkage detection from elastic registration of chest CT scans in patients with systemic sclerosis (SSc). Materials and Methods Patients with SSc evaluated between January 2009 and October 2017 who had undergone at least two unenhanced supine CT scans of the chest and pulmonary function tests (PFTs) performed within 3 months were retrospectively included.

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Article Synopsis
  • * The study examines the effects of three normalization methods and two discretization methods on radiomics features in brain MRI, establishing guidelines for consistent future research.
  • * Using two datasets, results demonstrate that proper intensity normalization significantly enhances the stability of extracted features, which can improve the accuracy of machine learning algorithms in classifying tumor grades.
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Article Synopsis
  • Radiation therapy is an important treatment for cancer that has improved a lot recently because of new technology and better imaging.
  • * Machine learning, especially through something called radiomics, helps doctors make better decisions about treating cancer by analyzing medical images.
  • * This review looks at a lot of studies to find out how radiomics can help with things like predicting how well treatments work and managing patient care more accurately, but it also points out some issues that need to be fixed.
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Article Synopsis
  • The study evaluates how various factors affect the quality of pseudo computed tomography (pCT) generated from magnetic resonance imaging (MRI) using a 3D convolutional neural network (CNN).
  • It includes analysis of 402 brain tumor cases, examining different MRI sequences and standardization approaches, while also comparing two specific neural network architectures (HighResNet and 3D UNet).
  • Results show that larger training datasets improve pCT quality, with the best pCTs produced from >200 samples, and reveal that specific standardization methods (like white stripe) yield lower errors compared to others.
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Article Synopsis
  • The paper focuses on improving medical image analysis by addressing image registration and tumor segmentation simultaneously using a new deep learning algorithm.
  • The proposed method utilizes the interdependence between registration and segmentation tasks, specifically adjusting similarity constraints within tumor regions for better results.
  • The algorithm was tested on well-known datasets (BraTS 2018 and OASIS 3), showing competitive performance compared to state-of-the-art methods, especially in tumor areas, and is accessible for public use online.
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Artificial intelligence is a hot topic in medical imaging. The development of deep learning methods and in particular the use of convolutional neural networks (CNNs), have led to substantial performance gain over the classic machine learning techniques. Multiple usages are currently being evaluated, especially for thoracic imaging, such as such as lung nodule evaluation, tuberculosis or pneumonia detection or quantification of diffuse lung diseases.

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Relevance and penetration of machine learning in clinical practice is a recent phenomenon with multiple applications being currently under development. Deep learning-and especially convolutional neural networks (CNNs)-is a subset of machine learning, which has recently entered the field of thoracic imaging. The structure of neural networks, organized in multiple layers, allows them to address complex tasks.

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