Scholars@Duke
Ehsan Abadi

Ehsan Abadi

Associate Professor in Radiology
Radiology

Scholarly Works - Conferences

An integrated PET-CT simulation pipeline for biomedical imaging research

Conference Progress in Biomedical Optics and Imaging Proceedings of SPIE · January 1, 2025 Positron emission tomography-computed tomography (PET-CT) is a frequently used multimodality imaging technique. PET scans utilize a radioactive tracer to record metabolic activity, and CT scans provide anatomical information through x-ray attenuation. The ... Full text Cite

The Utility of Photon-Counting CT Localizer Radiograph in Bone Densitometry

Conference Progress in Biomedical Optics and Imaging Proceedings of SPIE · January 1, 2025 Osteoporosis is a prevalent but underdiagnosed condition that significantly increases fracture risk, leading to substantial healthcare costs. Dual-energy X-ray absorptiometry (DEXA) remains the gold standard for areal bone mineral density (aBMD) assessment ... Full text Cite

Variability in patient CT radiation dose and image quality: the impact of positioning and body habitus via a virtual imaging trial study

Conference Progress in Biomedical Optics and Imaging Proceedings of SPIE · January 1, 2025 Computed tomography (CT) dose and image quality data exhibit a large variability even for the same patient size. That is so despite the tube current modulation (TCM) systems adjusting radiation exposure according to patient body habitus to achieve consiste ... Full text Cite

Reproducibility of Lung Density Quantifications in Photon-counting CT: A Multi-center Phantom Study

Conference AMERICAN JOURNAL OF RESPIRATORY AND CRITICAL CARE MEDICINE · May 1, 2024 Link to item Cite

Virtual patients for clinical trials

Conference RADIOTHERAPY AND ONCOLOGY · May 2024 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

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

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

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

Emphysema Score in CT for COPD Quantifications Using Artificial Intelligence Informed by Virtual Imaging Datasets

Conference AMERICAN JOURNAL OF RESPIRATORY AND CRITICAL CARE MEDICINE · May 1, 2023 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

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

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

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

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 (50< ... Full text 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

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

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

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

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