Scholars@Duke
Ehsan Abadi

Ehsan Abadi

Associate Professor in Radiology
Radiology

Selected Publications

A framework to model charge sharing and pulse pileup for virtual imaging trials of photon-counting CT.

Journal Article Physics in medicine and biology · November 2024 Objective.This study describes the development, validation, and integration of a detector response model that accounts for the combined effects of x-ray crosstalk, charge sharing, and pulse pileup in photon-counting detectors.Approach.The x-r ... Full text Cite

Toward widespread use of virtual trials in medical imaging innovation and regulatory science.

Journal Article Med Phys · October 6, 2024 The rapid advancement in the field of medical imaging presents a challenge in keeping up to date with the necessary objective evaluations and optimizations for safe and effective use in clinical settings. These evaluations are traditionally done using clin ... Full text Link to item Cite

Estimation of threshold thickness of residual normal tissue in lung dysfunction detectable by dynamic chest radiography: A virtual imaging trial.

Journal Article Med Phys · September 2024 BACKGROUND: Dynamic chest radiography (DCR) is a recently developed functional x-ray imaging technique that detects pulmonary ventilation impairment as a decrease in changes in lung density during respiration. However, the diagnostic performance of DCR is ... Full text Link to item Cite

Photon-counting computed tomography versus energy-integrating computed tomography for detection of small liver lesions: comparison using a virtual framework imaging.

Journal Article Journal of medical imaging (Bellingham, Wash.) · September 2024 PurposePhoton-counting computed tomography (PCCT) has the potential to provide superior image quality to energy-integrating CT (EICT). We objectively compare PCCT to EICT for liver lesion detection.ApproachFifty anthropomorphic, computati ... Full text Cite

A systematic assessment and optimization of photon-counting CT for lung density quantifications.

Journal Article Med Phys · April 2024 BACKGROUND: Photon-counting computed tomography (PCCT) has recently emerged into clinical use; however, its optimum imaging protocols and added benefits remains unknown in terms of providing more accurate lung density quantification compared to energy-inte ... Full text Open Access Link to item Cite

Development of physiologically-informed computational coronary artery plaques for use in virtual imaging trials.

Journal Article Med Phys · March 2024 BACKGROUND: As a leading cause of death, worldwide, cardiovascular disease is of great clinical importance. Among cardiovascular diseases, coronary artery disease (CAD) is a key contributor, and it is the attributed cause of death for 10% of all deaths ann ... Full text Link to item Cite

Protocol selection formalism for minimizing detectable differences in morphological radiomics features of lung lesions in repeated CT acquisitions.

Journal Article J Med Imaging (Bellingham) · March 2024 BACKGROUND: The accuracy of morphological radiomic features (MRFs) can be affected by various acquisition settings and imaging conditions. To ensure that clinically irrelevant changes do not reduce sensitivity to capture the radiomics changes between succe ... Full text Link to item Cite

A systematic task-based image quality assessment of photon-counting and energy integrating CT as a function of reconstruction kernel and phantom size.

Journal Article Med Phys · February 2024 BACKGROUND: Image quality of photon-counting and energy integrating CT scanners changes with object size, dose to the object, and kernel selection. PURPOSE: To comprehensively compare task-generic image quality of photon-counting CT (PCCT) and energy integ ... Full text Link to item Cite

Deep silicon photon-counting CT: A first simulation-based study for assessing perceptual benefits across diverse anatomies.

Journal Article Eur J Radiol · February 2024 OBJECTIVES: To assess perceptual benefits provided by the improved spatial resolution and noise performance of deep silicon photon-counting CT (Si-PCCT) over conventional energy-integrating CT (ECT) using polychromatic images for various clinical tasks and ... Full text Link to item Cite

Quantitative accuracy of lung function measurement using parametric response mapping: A virtual imaging study.

Conference Proc SPIE Int Soc Opt Eng · February 2024 Parametric response mapping (PRM) is a voxel-based quantitative CT imaging biomarker that measures the severity of chronic obstructive pulmonary disease (COPD) by analyzing both inspiratory and expiratory CT scans. Although PRM-derived measurements have be ... Full text Link to item Cite

Development and Application of a Virtual Imaging Trial Framework for Longitudinal Quantification of Emphysema in CT.

Journal Article Proc SPIE Int Soc Opt Eng · February 2024 Pulmonary emphysema is a progressive lung disease that requires accurate evaluation for optimal management. This task, possible using quantitative CT, is particularly challenging as scanner and patient attributes change over time, negatively impacting the ... Full text Link to item Cite

Virtual NLST: Towards Replicating National Lung Screening Trial

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2024 Virtual Imaging Trials, known as VITs, provide a computational substitute for clinical trials. These traditional trials tend to be sluggish, costly, and frequently deficient in definitive evidence, all the while subjecting participants to ionizing radiatio ... Full text Cite

Synthesizing heterogeneous lung lesions for virtual imaging trials

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2024 Virtual imaging trials of malignancies require realistic models of lesions. The purpose of this study was to create hybrid lesion models and associated tool incorporating morphological and textural realism. The developed tool creates a lesion morphology ba ... Full text Cite

Deep learning-based algorithm to segment pediatric and adult lungs from dynamic chest radiography images using virtual patient datasets

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2024 Dynamic chest radiography (DCR) enables the evaluation of lung function based on changes in lung density, lung area, and diaphragm level due to respiration. The need for lung segmentation techniques for sequential chest images is growing. Thus, this study ... Full text Cite

A comparative study on the utility and choice parameters of photon-counting CT for bone quantification

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2024 The measurements of bone macro- and microstructures provide major insight into bone health and risk fracture. The accuracy of these measurements is limited when Conventional CT is used. However, CT technology has advanced with the introduction of photon-co ... Full text Cite

A generic model of semiconductor-based photon-counting detectors for spectral CT

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2024 Photon-counting CT (PCCT) is an emerging x-ray spectral imaging technology. There are several PCCT prototypes available for clinical and experimental applications. Despite many published results, objective quantitative evaluation of PCCT systems remains ch ... Full text Cite

A Physics-informed Deep Neural Network for Harmonization of CT Images

Journal Article IEEE Transactions on Biomedical Engineering · January 1, 2024 Computed Tomography (CT) quantification is affected by the variability in image acquisition and rendition. This paper aimed to reduce this variability by harmonizing the images utilizing physics-based deep neural networks (DNNs). Methods: An a ... Full text Cite

Surface-based anthropomorphic bone structures for use in high-resolution simulated medical imaging.

Journal Article Phys Med Biol · December 28, 2023 Objective.Virtual imaging trials enable efficient assessment and optimization of medical image devices and techniques via simulation rather than physical studies. These studies require realistic, detailed ground-truth models or phantoms of the relevant ana ... Full text Link to item Cite

Modeling and identification of affective parameters on cadmium's durability and evaluating cadmium pollution indicators caused by using chemical fertilizers in long term.

Journal Article Environ Geochem Health · December 2023 Soil contamination by anthropogenic heavy metals has become a global issue. This study aimed to investigate cadmium (Cd) concentration, mobility, and contamination indices of Cd in soils in the Hamadan province, west of Iran. To investigate the concentrati ... Full text Link to item Cite

Clinical and radiation risk across one million patients in Computed Tomography: influence of age, size, and race

Conference · November 26, 2023 Purpose. We recently developed a mathematical model to balance radiation risk and clinical risk, namely the risk of misdiagnosis due to insufficient image quality. In this work, we applied this model to a population of one million CT imaging cases to evalu ... Open Access Cite

Exploration of the pulse pileup effects in a clinical CdTe-based photon-counting computed tomography.

Journal Article Med Phys · November 2023 BACKGROUND: High tube current generates a high flux of x-rays to photon counting detectors (PCDs) that can potentially result in the piling up of pulses formed by concurrent photons, which can cause count loss and energy resolution degradation. PURPOSE: To ... Full text Link to item Cite

Coronary stenosis quantification in cardiac computed tomography angiography: multi-factorial optimization of image quality and radiation dose.

Journal Article J Med Imaging (Bellingham) · November 2023 BACKGROUND: The accuracy and variability of quantification in computed tomography angiography (CTA) are affected by the interplay of imaging parameters and patient attributes. The assessment of these combined effects has been an open engineering challenge. ... Full text Link to item Cite

Development and Testing of a Clinical Tool to Predict and Optimize Liver Contrast-Enhanced CT Imaging

Conference https://aapm.onlinelibrary.wiley.com/doi/epdf/10.1002/mp.16525 · July 23, 2023 Achieving consistent and sufficient hepatic parenchyma contrast enhancement (HPCE) level can improve diagnostic performance and reduce enhancement variability; this raises the baseline image quality and optimize injection practices, both carries economic a ... Full text Open Access Link to item Cite

Accuracy of Noise Magnitude Measurements from Patient CT Images

Conference https://aapm.onlinelibrary.wiley.com/doi/epdf/10.1002/mp.16525 · July 23, 2023 Purpose Noise magnitude is a main CT image quality indicator. In vivo measurements emerged as a patient-specific methodology to assess and qualify CT noise, yet methods to do so vary. Current noise measurement methods in soft tissues and air surrounding t ... Full text Open Access Link to item Cite

Can Photon-Counting CT Improve Estimation Accuracy of Morphological Radiomics Features? A Simulation Study for Assessing the Quantitative Benefits from Improved Spatial Resolution in Deep Silicon-Based Photon-Counting CT.

Journal Article Acad Radiol · June 2023 RATIONALE AND OBJECTIVES: Deep silicon-based photon-counting CT (Si-PCCT) is an emerging detector technology that provides improved spatial resolution by virtue of its reduced pixel sizes. This article reports the outcomes of the first simulation study eva ... Full text Link to item Cite

Emphysema Quantifications With CT Scan: Assessing the Effects of Acquisition Protocols and Imaging Parameters Using Virtual Imaging Trials.

Journal Article Chest · May 2023 BACKGROUND: CT scan has notable potential to quantify the severity and progression of emphysema in patients. Such quantification should ideally reflect the true attributes and pathologic conditions of subjects, not scanner parameters. To achieve such an ob ... Full text Link to item Cite

Harmonizing CT Images via Physics-based Deep Neural Networks.

Journal Article Proc SPIE Int Soc Opt Eng · February 2023 The rendition of medical images influences the accuracy and precision of quantifications. Image variations or biases make measuring imaging biomarkers challenging. The objective of this paper is to reduce the variability of computed tomography (CT) quantif ... Full text Link to item Cite

A systematic assessment of photon-counting CT for bone mineral density and microarchitecture quantifications.

Journal Article Proc SPIE Int Soc Opt Eng · February 2023 Photon-counting CT (PCCT) is an emerging imaging technology with potential improvements in quantification and rendition of micro-structures due to its smaller detector sizes. The aim of this study was to assess the performance of a new PCCT scanner (NAEOTO ... Link to item Cite

Development and Application of a Virtual Imaging Trial framework for Airway Quantifications via CT.

Journal Article Proc SPIE Int Soc Opt Eng · February 2023 Chronic obstructive pulmonary disease (COPD) is one of the top three causes of death worldwide, characterized by emphysema and bronchitis. Airway measurements reflect the severity of bronchitis and other airway-related diseases. Airway structures can be ob ... Full text Link to item Cite

Phase-contrast virtual chest radiography.

Journal Article Proc Natl Acad Sci U S A · January 3, 2023 Respiratory X-ray imaging enhanced by phase contrast has shown improved airway visualization in animal models. Limitations in current X-ray technology have nevertheless hindered clinical translation, leaving the potential clinical impact an open question. ... Full text Link to item Cite

CT-HARMONICA: physics-based CT harmonization for reliable lung density quantification

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2023 Pulmonary emphysema is a form of Chronic Obstructive Pulmonary Disease (COPD) and a chronic lung condition that results in a breakdown of alveoli walls. Quantitative Computed Tomography (CT) is increasingly used to assess the presence or progression of emp ... Full text Cite

Bone suppression technique for multidirectional dynamic chest radiography: A virtual imaging trial

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2023 Prediction of pleural invasion in lung cancer is crucial in planning appropriate operating procedures and can be assessed using dynamic chest radiography (DCR). However, this assessment is negatively affected by rib shadows in conventional images. The purp ... Full text Cite

Automatic quality control in computed tomography volumes segmentation using a small set of XCAT as reference images

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2023 Deep learning methods have performed superiorly to segment organs of interest from Computed Tomography images than traditional methods. However, the trained models do not generalize well at the inference phase, and manual validation and correction are not ... Full text Cite

Task-based validation and application of a scanner-specific CT simulator using an anthropomorphic phantom.

Journal Article Med Phys · December 2022 BACKGROUND: Quantitative analysis of computed tomography (CT) images traditionally utilizes real patient data that can pose challenges with replicability, efficiency, and radiation exposure. Instead, virtual imaging trials (VITs) can overcome these hurdles ... Full text Link to item Cite

A patient-informed approach to predict iodinated-contrast media enhancement in the liver.

Journal Article Eur J Radiol · November 2022 OBJECTIVE: To devise a patient-informed time series model that predicts liver contrast enhancement, by integrating clinical data and pharmacokinetics models, and to assess its feasibility to improve enhancement consistency in contrast-enhanced liver CT sca ... Full text Open Access Link to item Cite

Anatomically and physiologically informed computational model of hepatic contrast perfusion for virtual imaging trials.

Journal Article Med Phys · May 2022 PURPOSE: Virtual (in silico) imaging trials (VITs), involving computerized phantoms and models of the imaging process, provide a modern alternative to clinical imaging trials. VITs are faster, safer, and enable otherwise-impossible investigations. Current ... Full text Link to item Cite

Correction for Systematic Bias in Radiomics Measurements Due to Variation in Imaging Protocols.

Journal Article Acad Radiol · April 2022 RATIONALE AND OBJECTIVES: The accuracy of measured radiomics features is affected by CT imaging protocols. This study aims to ascertain if applying bias corrections can improve the classification performance of the radiomics features. MATERIALS AND METHODS ... Full text Link to item Cite

Quantitative analysis of changes in lung density by dynamic chest radiography in association with CT values: a virtual imaging study and initial clinical corroboration.

Journal Article Radiol Phys Technol · March 2022 Dynamic chest radiography (DCR) identifies pulmonary impairments as decreased changes in radiographic lung density during respiration (Δpixel values), but not as scaled/standardized computed tomography (CT) values. Quantitative analysis correlated with CT ... Full text Link to item Cite

Corrections to "iPhantom: A Framework for Automated Creation of Individualized Computational Phantoms and its Application to CT Organ Dosimetry".

Journal Article IEEE J Biomed Health Inform · January 2022 In [1], the dose estimation accuracy using the alternative baseline method under modulated tube current was not correctly calculated due to an unintentional simulation error. ... Full text Link to item Cite

Comparing two different noise magnitude estimation methods in CT using virtual imaging trials

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2022 Several methods have been introduced over the years to measure CT image noise magnitudes in vivo applying different image segmentation strategies, HU thresholds, and regions of interests in which the noise is calculated. Therefore, it is impossible to dire ... Full text Open Access Cite

Inter- and intra-scan variability for lung imaging quantifications via CT.

Journal Article Proc SPIE Int Soc Opt Eng · 2022 CT imaging provides physicians valuable insights when diagnosing disease in a clinical setting. In order to provide an accurate diagnosis, is it important to have a high accuracy with controlled variability across CT scans from different scanners and imagi ... Full text Link to item Cite

Scanner-specific validation of a CT simulator using a COPD-emulated anthropomorphic phantom.

Journal Article Proc SPIE Int Soc Opt Eng · 2022 Traditional methods of quantitative analysis of CT images typically involve working with patient data, which is often expensive and limited in terms of ground truth. To counter these restrictions, quantitative assessments can instead be made through Virtua ... Full text Link to item Cite

Development and Clinical Applications of a Virtual Imaging Framework for Optimizing Photon-counting CT.

Journal Article Proc SPIE Int Soc Opt Eng · 2022 The purpose of this study was to develop a virtual imaging framework that simulates a new photon-counting CT (PCCT) system (NAEOTOM Alpha, Siemens). The PCCT simulator was built upon the DukeSim platform, which generates projection images of computational ... Full text Link to item Cite

Photon-counting CT versus conventional CT for COPD quantifications: intra-scanner optimization and inter-scanner assessments using virtual imaging trials.

Journal Article Proc SPIE Int Soc Opt Eng · 2022 Chronic obstructive pulmonary disease (COPD) is a chronic inflammatory lung disease and a major cause of death and disability worldwide. Quantitative CT is a powerful tool to better understand the heterogeneity and severity of this disease. Quantitative CT ... Full text Link to item Cite

A truth-based primal-dual learning approach to reconstruct CT images utilizing the virtual imaging trial platform.

Journal Article Proc SPIE Int Soc Opt Eng · 2022 Inherent to Computed tomography (CT) is image reconstruction, constructing 3D voxel values from noisy projection data. Modeling this inverse operation is not straightforward. Given the ill-posed nature of inverse problem in CT reconstruction, data-driven m ... Full text Link to item Cite

Quality or quantity: toward a unified approach for multi-organ segmentation in body CT

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2022 Organ segmentation of medical images is a key step in virtual imaging trials. However, organ segmentation datasets are limited in in terms of quality (because labels cover only a few organs) and quantity (since case numbers are limited). In this study, we ... Full text Cite

Simulation of the combined effects of charge sharing and pulse pileup in photon-counting CT

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2022 Photon-counting CT (PCCT) is an emerging CT technology that uses photon-counting detectors (PCDs) to offer better spatial resolution, higher contrast, lower noise, and material-specific imaging as compared to conventional energy-integrating CT. To study th ... Full text Cite

Cardiac CT reconstruction for vendor-neutral virtual imaging trials

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2022 Cardiac CT imaging is invaluable in a variety of applications including non-invasive assessment of coronary artery calcifications, the ruling out of acute coronary artery syndrome, and the planning of valve replacement procedures. Newer applications includ ... Full text Cite

Optimization of imaging conditions in pediatric dynamic chest radiography: a virtual imaging trial

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2022 Ventilatory impairment is detected as decreased changes in lung density during respiration in dynamic chest radiography (DCR). The purpose of this study was to determine optimum imaging conditions in pediatric DCR through a virtual imaging trial (VIT). An ... Full text Cite

Virtual versus reality: external validation of COVID-19 classifiers using XCAT phantoms for chest radiography

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2022 Many published studies use deep learning models to predict COVID-19 from chest x-ray (CXR) images, often reporting high performances. However, the models do not generalize well on independent external testing. Common limitations include the lack of medical ... Full text Cite

Virtual vs. reality: External validation of COVID-19 classifiers using XCAT phantoms for chest computed tomography

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2022 Research studies of artificial intelligence models in medical imaging have been hampered by poor generalization. This problem has been especially concerning over the last year with numerous applications of deep learning for COVID-19 diagnosis. Virtual imag ... Full text Cite

Optimization of imaging parameters of an investigational photon-counting CT prototype for lung lesion radiomics

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2022 The aim of this study was to evaluate and optimize the imaging parameters of a new dual-source photon-counting CT (PCCT) scanner (NAEOTOM Alpha, Siemens Healthineers) for lung lesion radiomics using virtual imaging trials. Virtual patients (XCAT phantoms) ... Full text Cite

Development, validation, and relevance of in vivo low-contrast task transfer function to estimate detectability in clinical CT images.

Journal Article Medical physics · December 2021 PurposeThe current state-of-the-art calculation of detectability index (d') is largely phantom-based, with the latest being based on a hybrid phantom noise power spectrum (NPS) combined with patient-specific noise magnitude and high-contrast air-s ... Full text Cite

Deep learning classification of COVID-19 in chest radiographs: performance and influence of supplemental training.

Journal Article J Med Imaging (Bellingham) · November 2021 Purpose: Accurate classification of COVID-19 in chest radiographs is invaluable to hard-hit pandemic hot spots. Transfer learning techniques for images using well-known convolutional neural networks show promise in addressing this problem. These methods ca ... Full text Open Access Link to item Cite

A scanner-specific framework for simulating CT images with tube current modulation.

Journal Article Physics in medicine and biology · September 2021 Although tube current modulation (TCM) is routinely implemented in modern computed tomography (CT) scans, no existing CT simulator is capable of generating realistic images with TCM. The goal of this study was to develop such a framework to (1) facilitate ... Full text Cite

Development and validation of an automated methodology to assess perceptual in vivo noise texture in liver CT.

Journal Article J Med Imaging (Bellingham) · September 2021 Purpose: Developing, validating, and evaluating a method for measuring noise texture directly from patient liver CT images (i.e., in vivo). Approach: The method identifies target regions within patient scans that are least likely to have major contribution ... Full text Link to item Cite

iPhantom: A Framework for Automated Creation of Individualized Computational Phantoms and Its Application to CT Organ Dosimetry.

Journal Article IEEE J Biomed Health Inform · August 2021 OBJECTIVE: This study aims to develop and validate a novel framework, iPhantom, for automated creation of patient-specific phantoms or "digital-twins (DT)" using patient medical images. The framework is applied to assess radiation dose to radiosensitive or ... Full text Link to item Cite

Assessment of pleural invasion and adhesion of lung tumors with dynamic chest radiography: A virtual clinical imaging study.

Journal Article Med Phys · April 2021 PURPOSE: Accurate preoperative assessment of tumor invasion/adhesion is crucial for planning appropriate operative procedures. Recent advances in digital radiography allow a motion analysis of lung tumors with dynamic chest radiography (DCR) with total exp ... Full text Link to item Cite

A GPU-accelerated framework for rapid estimation of scanner-specific scatter in CT for virtual imaging trials.

Journal Article Phys Med Biol · March 23, 2021 Virtual imaging trials (VITs), defined as the process of conducting clinical imaging trials using computer simulations, offer a time- and cost-effective alternative to traditional imaging trials for CT. The clinical potential of VITs hinges on the realism ... Full text Link to item Cite

Classification of COVID-19 in chest radiographs: assessing the impact of imaging parameters using clinical and simulated images

Journal Article Proc. SPIE 11597, Medical Imaging 2021: Computer-Aided Diagnosis, 115970A · February 15, 2021 As computer-aided diagnostics develop to address new challenges in medical imaging, including emerging diseases such as COVID-19, the initial development is hampered by availability of imaging data. Deep learning algorithms are particularly notorious for p ... Full text Open Access Link to item Cite

Estimation of in vivo noise in clinical CT images: comparison and validation of three different methods against ensemble noise gold-standard

Journal Article Proc. SPIE 11595, Medical Imaging 2021: Physics of Medical Imaging, 115952P · February 15, 2021 Image quality estimation is crucial in modern CT with noise magnitude playing a key role. Several methods have been proposed to estimate noise surrogates in vivo. This study aimed to ascertain the accuracy of three different noise-magnitude estimation meth ... Open Access Link to item Cite

Virtual Imaging Trials for Coronavirus Disease (COVID-19).

Journal Article AJR Am J Roentgenol · February 2021 Featured Publication OBJECTIVE. The virtual imaging trial is a unique framework that can greatly facilitate the assessment and optimization of imaging methods by emulating the imaging experiment using representative computational models of patients and validated imaging simula ... Full text Link to item Cite

A framework to simulate ct images with tube current modulation

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2021 Tube current modulation (TCM) is routinely implemented in clinical CT imaging. By modifying the x-ray tube current as a function of patient attenuation, image quality can be made more consistent and radiation dose can be better managed. Optimal TCM setting ... Full text Cite

An analysis of radiomics features in lung lesions in covid-19

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2021 Radiomic features extracted from CT imaging can be used to quantitively assess COVID-19. The objective of this work was to extract and analyze radiomics features in RT-PRC confirmed COVID-19 cases to identify relevant characteristics for COVID-19 diagnosis ... Full text Cite

An experimental evaluation of material separability in photon-counting ct

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2021 Signal separability is an important factor in the differentiation of materials in spectral computed tomography. In this work, we evaluated the separability of two such materials, iodine and gadolinium with k-edges of 33.1 keV and 50.2 keV, respectively, wi ... Full text Cite

A probabilistic conditional adversarial neural network to reduce imaging variation in radiography

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2021 Medical images can vary due to differences in imaging equipment and conditions. This variability negatively can impact the consistency and accuracy of diagnostic processes. Hence, it is critical to decrease the variability in image acquisition to achieve c ... Full text Cite

Copd quantifications via ct imaging: Ascertaining the effects of acquisition protocol using virtual imaging trial

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2021 COPD is the fourth leading cause of death in the United States. The structural and functional attributes of this disease can be assessed in vivo using computed tomography (CT). The value of quantitative CT has been demonstrated towards characterization and ... Full text Cite

Estimation of lung volume changes from frontal and lateral views of dynamic chest radiography using a convolutional neural network model: A computational phantom study

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2021 TWe aimed to estimate respiratory changes in lung volumes (i"lung volume) using frontal and lateral dynamic chest radiography (DCR) by employing a convolutional neural network (CNN) learning approach trained and tested using the four-dimensional (4D) exten ... Full text Cite

Multivariate snr in spectral computed tomography

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2021 In this work, we define a theoretical approach to characterizing the signal-to-noise ratio (SNR) of multi-channeled systems such as spectral computed tomography image series. Spectral image datasets encompass multiple near-simultaneous acquisitions that sh ... Full text Cite

Optimization of CT angiography using physiologically-informed computational plaques, dynamic XCAT phantoms, and physics-based CT simulation

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2021 Cardiovascular disease is a leading cause of death worldwide. Among all cardiovascular diseases, coronary artery disease (CAD) is a major contributor to mortality, accounting for approximately 10% of deaths per annum. Imaging techniques such as computed to ... Full text Cite

Multi-factorial optimization of imaging parameters for quantifying coronary stenosis in cardiac ct

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2021 The accuracy and variability of quantifications in Computed Tomography Angiography (CTA) are affected by imaging parameters and patient attributes. While patient attributes cannot usually be altered for a scan, imaging parameters can be optimized to improv ... Full text Cite

Correlation of respiratory changes in lung density on dynamic chest radiographs with changes in the ct value: A computational phantom study

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2021 Pulmonary impairments are observed as decreased changes in lung density during respiration on dynamic chest radiographs (DCR). To facilitate pulmonary function evaluation based on DCR, the present study was conducted to correlate respiratory changes in pix ... Full text Cite

Virtual Imaging Trials for Novel Coronavirus Disease (COVID-19)

Conference · December 2, 2020 PURPOSE Virtual imaging trial is a unique framework that can greatly facilitate the assessment and optimization of imaging, by emulating the experiments using representative models of patients and scanners. This study aimed to impalement and demonstrate a ... Cite

A comparison of COVID-19 and imaging radiation risk in clinical patient populations.

Journal Article J Radiol Prot · November 11, 2020 The outbreak of coronavirus SARS-COV2 affected more than 180 countries necessitating fast and accurate diagnostic tools. Reverse transcriptase polymerase chain reaction (RT-PCR) has been identified as a gold standard test with Chest CT and Chest Radiograph ... Full text Open Access Link to item Cite

Virtual clinical trials in medical imaging: a review.

Journal Article J Med Imaging (Bellingham) · July 2020 Featured Publication The accelerating complexity and variety of medical imaging devices and methods have outpaced the ability to evaluate and optimize their design and clinical use. This is a significant and increasing challenge for both scientific investigations and clinical ... Full text Link to item Cite

Virtual clinical trial for quantifying the effects of beam collimation and pitch on image quality in computed tomography.

Journal Article J Med Imaging (Bellingham) · July 2020 Purpose: To utilize a virtual clinical trial (VCT) construct to investigate the effects of beam collimation and pitch on image quality (IQ) in computed tomography (CT) under different respiratory and cardiac motion rates. Approach: A computational human mo ... Full text Link to item Cite

Patient-Informed and Physiology-Based Modelling of Hepatic Contrast Dynamics in Contrast-Enhanced CT Imaging

Journal Article · March 16, 2020 PURPOSE Iodinated contrast agents are commonly used in CT imaging to enhance tissue contrast. Consistency in contrast enhancement (CE) is critical in radiological diagnosis. Contrast material circulation in individual patients is affected by factors such a ... Open Access Cite

Optimization of energy thresholds in photon-counting CT via a virtual clinical trial

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2020 In photon-counting CT, detector energy thresholds directly affect image quality attributes such as contrast and noise. The purpose of this study was to identify optimum energy thresholds using a comprehensive virtual clinical trial platform. The virtual tr ... Full text Cite

Virtual imaging trials: An emerging experimental paradigm in imaging research and practice

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2020 As medical imaging technologies continue to accelerate in complexity, application, and multiplicity of design choices and use features, they should ideally be evaluated and optimized through human clinical trials. However, such trials are often impossible ... Full text Cite

In vivo noise texture estimation: Development and validation of an automated methodology

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2020 The purpose of this study was to develop, validate, and evaluate a method for measuring noise texture directly from patient CT images (i.e., “in vivo”). The method identifies target regions within patient scans which are least likely to have major contribu ... Full text Cite

Prediction of pleural invasion of lung cancer with dynamic chest radiography: A simulation study

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2020 We aimed to investigate the feasibility of predicting pleural invasion or adhesion of lung cancers with dynamic chest radiography (DCR), using a four-dimensional (4D) extended cardiac-torso (XCAT) computational phantom. An XCAT phantom of an adult man (50t ... Full text Cite

Modeling Patient-Informed Liver Contrast Perfusion in Contrast-enhanced Computed Tomography.

Journal Article J Comput Assist Tomogr · 2020 OBJECTIVE: To determine the correlation between patient attributes and contrast enhancement in liver parenchyma and demonstrate the potential for patient-informed prediction and optimization of contrast enhancement in liver imaging. METHODS: The study incl ... Full text Open Access Link to item Cite

A real-time Monte Carlo tool for individualized dose estimations in clinical CT.

Journal Article Phys Med Biol · November 4, 2019 The increasing awareness of the adverse effects associated with radiation exposure in computed tomography (CT) has necessesitated the quantification of dose delivered to patients for better risk assessment in the clinic. The current methods for dose quanti ... Full text Link to item Cite

Validation of algorithmic CT image quality metrics with preferences of radiologists.

Journal Article Med Phys · November 2019 PURPOSE: Automated assessment of perceptual image quality on clinical Computed Tomography (CT) data by computer algorithms has the potential to greatly facilitate data-driven monitoring and optimization of CT image acquisition protocols. The application of ... Full text Open Access Link to item Cite

Development of a scanner-specific simulation framework for photon-counting computed tomography.

Journal Article Biomed Phys Eng Express · August 2019 Featured Publication The aim of this study was to develop and validate a simulation platform that generates photon-counting CT images of voxelized phantoms with detailed modeling of manufacturer-specific components including the geometry and physics of the x-ray source, source ... Full text Link to item Cite

Systematic analysis of bias and variability of texture measurements in computed tomography.

Journal Article J Med Imaging (Bellingham) · July 2019 Texture is a key radiomics measurement for quantification of disease and disease progression. The sensitivity of the measurements to image acquisition, however, is uncertain. We assessed bias and variability of computed tomography (CT) texture feature meas ... Full text Link to item Cite

DukeSim: A Realistic, Rapid, and Scanner-Specific Simulation Framework in Computed Tomography.

Journal Article IEEE Trans Med Imaging · June 2019 Featured Publication The purpose of this study was to develop a CT simulation platform that is: 1) compatible with voxel-based computational phantoms; 2) capable of modeling the geometry and physics of commercial CT scanners; and 3) computationally efficient. Such a simulation ... Full text Link to item Cite

Modeling "Textured" Bones in Virtual Human Phantoms.

Journal Article IEEE Trans Radiat Plasma Med Sci · January 2019 The purpose of this study was to develop detailed and realistic models of the cortical and trabecular bones in the spine, ribs, and sternum and incorporate them into the library of virtual human phantoms (XCAT). Cortical bone was modeled by 3D morphologica ... Full text Link to item Cite

A framework for realistic virtual clinical trials in photon counting computed tomography

Conference Medical Imaging 2019: Physics of Medical Imaging · 2019 Cite

Patient-informed and physiology-based modelling of contrast dynamics in cross-sectional imaging

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2019 Previous studies have shown that many factors including body habitus, sex, and age of the patient, as well as contrast injection protocol contribute to the variability in contrast-enhanced cross-sectional imaging (i.e., CT). We have previously developed a ... Full text Cite

Anatomically- and computationally-informed hepatic contrast perfusion simulations for use in virtual clinical trials

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2019 This study modeled a framework for virtual human liver phantoms, focusing primarily on the intricate vascular networks that comprise the liver. Large vasculature was segmented from clinical liver perfusion images to ascertain a general starting point for t ... Full text Cite

Impact of energy threshold on material quantification of contrast agents in photon-counting CT

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2019 The purpose of this study was to examine the effect of energy threshold selection on the quantification of contrast agents in photon-counting CT (PCCT). A phantom was devised consisting of vials of iodine (4, 8, 16 mg/mL), gadolinium (4, 8, 16 mg/mL), and ... Full text Cite

Dynamic chest radiography for pulmonary function diagnosis: A validation study using 4D extended cardiac-torso (XCAT) phantom

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2019 This study was performed to investigate the detection performance of trapped air in dynamic chest radiography using 4D extended cardiac-torso (XCAT) phantom with a user-defined ground truth. An XCAT phantom of an adult male (50th percentile in height and w ... Full text Cite

A Novel Methodology for Automated Image Quality Assessment of Pediatric CT

Conference · November 25, 2018 PURPOSE To develop an effective and automated methodology for patient-specific image quality assessment of clinical pediatric body CT examinations. METHOD AND MATERIALS This IRB approved study evaluated 816 clinically performed (6/14-11/17), contrast-enh ... Cite

Beyond the DRL: Applying Automated Quality Metrics to Assess Pediatric CT Program Liver Lesion Detection Performance

Conference · November 25, 2018 PURPOSE To apply an automated program for evaluating pediatric body CT study quality which utilizes metrics of dose and image quality for optimization of liver lesion detection. METHOD AND MATERIALS With IRB approval, 880 clinical contrast-enhanced abdom ... Cite

Modeling Lung Architecture in the XCAT Series of Phantoms: Physiologically Based Airways, Arteries and Veins.

Journal Article IEEE Trans Med Imaging · March 2018 Featured Publication The purpose of this paper was to extend the extended cardiac-torso (XCAT) series of computational phantoms to include a detailed lung architecture including airways and pulmonary vasculature. Eleven XCAT phantoms of varying anatomy were used in this paper. ... Full text Link to item Cite

From patient-informed to patient-specific organ dose estimation in clinical computed tomography

Conference Medical Imaging 2018: Physics of Medical Imaging · 2018 Cite

Virtual clinical trial in action: Textured XCAT phantoms and scanner-specific CT simulator to characterize noise across CT reconstruction algorithms

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2018 Although non-linear CT systems offer improved image quality over conventional linear systems, they disrupt certain assumptions of the dependency of noise and resolution on radiation dose that are true of linear systems. As such, simplistic phantoms do not ... Full text Cite

A rapid GPU-based Monte-Carlo simulation tool for individualized dose estimations in CT

Conference Medical Imaging 2018: Physics of Medical Imaging · 2018 Cite

Development of a fast, voxel-based, and scanner-specific CT simulator for image-quality-based virtual clinical trials

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2018 This study aimed to develop a simulation framework to synthesize accurate and scanner-specific Computed Tomography (CT) images of voxel-based computational phantoms. Two phantoms were used in the simulations, a geometry-based Mercury phantom and a "texture ... Full text Cite

How reliable are texture measurements?

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2018 The purpose of this study was to assess the bias (objectivity) and variability (robustness) of computed tomography (CT) texture features (internal heterogeneities) across a series of image acquisition settings and reconstruction algorithms. We simulated a ... Full text Cite

Realistic lesion simulation: Application of hyperelastic deformation to lesion-local environment in lung CT

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2018 Lesion simulation programs can be used to insert realistic, generated lesions into anatomical images for further study. Most lesion simulation programs rely on insertion of a mask within an otherwise unchangeable, i.e., static surrounding - in reality, les ... Full text Cite

Patient-specific quantification of image quality: An automated technique for measuring the distribution of organ Hounsfield units in clinical chest CT images.

Journal Article Med Phys · September 2017 PURPOSE: To develop and validate an automated technique for measuring organ Hounsfield units (HUs) in clinical chest CT images. MATERIALS AND METHODS: An automated computer algorithm was developed to measure the distribution of HUs inside four major organs ... Full text Link to item Cite

Robustness and Accuracy of An Automated Solution for Measuring Image Noise, Spatial Resolution, Contrast, and Dose in Clinical CT Images: Efforts Towards Patient-Specific Quantifications of CT Image Quality and Radiation Dose

Conference Medical Physics · June 30, 2017 Purpose: To develop a robust and accurate automated solution for measuring image noise, spatial resolution, contrast, and radiation dose using clinical patient CT images. Methods: An automated infrastructure has been developed to measure the image quality ... Cite

Image Quality Monitoring: Variability in Contrast Enhancement Across a Clinical Population

Conference Medical Physics · June 30, 2017 Purpose: Iodinated contrast agents are commonly used in computed tomography (CT) to delineate vasculature and blood perfusion by enhancement of Hounsfield unit values. Contrast-enhancement is affected by anatomical and physiological factors, and varies acr ... Cite

Organ Dose Estimation for CT Localizer Images

Conference Medical Physics · June 30, 2017 Purpose: Current radiation dose estimation for CT localizer exams report a single CTDIvol value. Localizer exams with the same CTDIvol can be acquired as AP, PA, or lateral geometries, each of which carry different radiation burdens. The Purpose of this st ... Cite

The Effect of Contrast Material on Radiation Dose at CT: Part II. A Systematic Evaluation across 58 Patient Models.

Journal Article Radiology · June 2017 Purpose To estimate the radiation dose as a result of contrast medium administration in a typical abdominal computed tomographic (CT) examination across a library of contrast material-enhanced computational patient models. Materials and Methods In part II ... Full text Link to item Cite

Organ Dose Estimation for CT Localizer Images

Conference MEDICAL PHYSICS · June 1, 2017 Link to item Cite

Airways, vasculature, and interstitial tissue: Anatomically informed computational modeling of human lungs for virtual clinical trials

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2017 This study aimed to model virtual human lung phantoms including both non-parenchymal and parenchymal structures. Initial branches of the non-parenchymal structures (airways, arteries, and veins) were segmented from anatomical data in each lobe separately. ... Full text Cite

SU-F-I-45: An Automated Technique to Measure Image Contrast in Clinical CT Images.

Journal Article Med Phys · June 2016 PURPOSE: To develop and validate an automated technique for measuring image contrast in chest computed tomography (CT) exams. METHODS: An automated computer algorithm was developed to measure the distribution of Hounsfield units (HUs) inside four major org ... Full text Link to item Cite

TH-AB-207A-01: Contrast-Enhanced CT: Correlation of Radiation Dose and Biological Effect.

Journal Article Med Phys · June 2016 PURPOSE: The potential risk from CT is generally characterized in terms of radiation dose. The presence of iodinated-contrast medium increases radiation dose. However, it is unclear how much of this increase is biologically relevant. The purpose of this st ... Full text Link to item Cite

Prediction of glioblastoma multiforme response to bevacizumab treatment using diffusion and perfusion imaging

Conference 2015 22nd Iranian Conference on Biomedical Engineering, ICBME 2015 · February 9, 2016 Response to Bevacizumab in Glioblastoma Multiforme (GBM) is not the same for all patients who receive this antiangiogenic therapy. In this research, structural magnetic resonance images (MRI), Diffusion Tensor Images (DTI), and Dynamic Susceptibility Contr ... Full text Cite

A technique for multi-dimensional optimization of radiation dose, contrast dose, and image quality in CT imaging

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2016 The purpose of this study was to substantiate the interdependency of image quality, radiation dose, and contrast material dose in CT towards the patient-specific optimization of the imaging protocols. The study deployed two phantom platforms. First, a vari ... Full text Cite

Consequences of delayed diagnosis in treatment of retinoblastoma.

Journal Article Iran J Pediatr · August 2014 OBJECTIVE: One of the primary factors in managing patients with retinoblastoma is early diagnosis. The main idea of this study was to recognize the consequences of delay in diagnosis on therapy of the disease. METHODS: A retrospective review of all childre ... Link to item Cite