Radiology Commons^™

Chemical Structure Of Fe–Ni Nanoparticles For Efficient Oxygen Evolution Reaction Electrocatalysis, Prashant Acharya, Zachary J. Nelson, Mourad Benamara, Ryan H. Manso, Sergio I. Perez Bakovic, Mojtaba Abolhassani, Sungsik Lee, Benjamin Reinhart, Jingyi Chen, Lauren F. Greenlee

Chemical Engineering Faculty Publications and Presentations

Bimetallic iron–nickel-based nanocatalysts are perhaps the most active for the oxygen evolution reaction (OER) in alkaline electrolytes. Recent developments in literature have suggested that the ratio of iron and nickel in Fe–Ni thin films plays an essential role in the performance and stability of the catalysts. In this work, the metallic ratio of iron to nickel was tested in alloy bimetallic nanoparticles. Similar to thin films, nanoparticles with iron–nickel atomic compositions where the atomic iron percentage is ≤50% outperformed nanoparticles with iron–nickel ratios of >50%. Nanoparticles of Fe20Ni80, Fe50Ni50, and Fe80Ni20 compositions were evaluated and demonstrated to have overpotentials of …

Multi-Dimensional Extension Of The Alternating Minimization Algorithm In X-Ray Computed Tomography, Jingwei Lu

McKelvey School of Engineering Graduate Student Theses & Dissertations

X-ray computed tomography (CT) is an important and effective tool in medical and industrial

imaging applications. The state-of-the-art methods to reconstruct CT images have had

great development but also face challenges. This dissertation derives novel algorithms to

reduce bias and metal artifacts in a wide variety of imaging modalities and increase performance

in low-dose scenarios.

The most widely available CT systems still use the single-energy CT (SECT), which is

good at showing the anatomic structure of the patient body. However, in SECT image

reconstruction, energy-related information is lost. In applications like radiation treatment

planning and dose prediction, accurate energy-related information …

Multi-Dimensional Extension Of The Alternating Minimization Algorithm In X-Ray Computed Tomography, Jingwei Lu

McKelvey School of Engineering Graduate Student Theses & Dissertations

X-ray computed tomography (CT) is an important and effective tool in medical and industrial imaging applications. The state-of-the-art methods to reconstruct CT images have had great development but also face challenges. This dissertation derives novel algorithms to reduce bias and metal artifacts in a wide variety of imaging modalities and increase performance in low-dose scenarios. The most widely available CT systems still use the single-energy CT (SECT), which is good at showing the anatomic structure of the patient body. However, in SECT image reconstruction, energy-related information is lost. In applications like radiation treatment planning and dose prediction, accurate energy-related information …

Deep Learning, Medical Physics And Cargo Cult Science., Miguel Romero Phd, Gilmer Valdes Phd, Timothy Solberg Phd, Yannet Interian Phd

Creative Activity and Research Day - CARD

Deep learning algorithms have become widely popular, with considerable success in fields where datasets have hundreds of thousands or million points. As deep learning is increasingly applied to the fields of medical physics and radiation oncology, a reasonable question follows: are these techniques the best approach, given the unique conditions in our field? In this study, we investigate the dependence of dataset size on the performance of deep learning algorithms compared with more traditional radiomics-based methods.

Calibrated Short Tr Recovery Mri For Rapid Measurement Of Brain-Blood Partition Coefficient And Correction Of Quantitative Cerebral Blood Flow, Scott William Thalman

Theses and Dissertations--Biomedical Engineering

The high prevalence and mortality of cerebrovascular disease has led to the development of several methods to measure cerebral blood flow (CBF) in vivo. One of these, arterial spin labeling (ASL), is a quantitative magnetic resonance imaging (MRI) technique with the advantage that it is completely non-invasive. The quantification of CBF using ASL requires correction for a tissue specific parameter called the brain-blood partition coefficient (BBPC). Despite regional and inter-subject variability in BBPC, the current recommended implementation of ASL uses a constant assumed value of 0.9 mL/g for all regions of the brain, all subjects, and even all species.

The …

Renal Granulomatosis Post Intravesical Bacillus Calmette-Guerin Therapy For Non-Muscle-Invasive Bladder Cancer, Karen Tran-Harding, Rashmi T. Nair, Halemane S. Ganesh

Radiology Faculty Publications

Intravesical Bacillus Calmette–Guerin (BCG) immunotherapy is a proven, effective treatment for intermediate- and high-risk non-muscle-invasive bladder cancer. Minor side effects are common and expected but systemic effects can occur in < 5% of treated patients. We present a rare case of a 49-year-old male that presented with fever and chills after 3 weeks of intravesical BCG therapy post transurethral resection of bladder tumor. New renal lesions were present on contrast-enhanced computed tomography scan which was histologically proven to be necrotizing renal granulomatosis.

Deep Gaze Velocity Analysis During Mammographic Reading For Biometric Identification Of Radiologists, Hong-Jun Yoon, Folami Alamudun, Kathy Hudson, Garnetta Morin-Ducote, Georgia Tourassi

Journal of Human Performance in Extreme Environments

Several studies have confirmed that the gaze velocity of the human eye can be utilized as a behavioral biometric or personalized biomarker. In this study, we leverage the local feature representation capacity of convolutional neural networks (CNNs) for eye gaze velocity analysis as the basis for biometric identification of radiologists performing breast cancer screening. Using gaze data collected from 10 radiologists reading 100 mammograms of various diagnoses, we compared the performance of a CNN-based classification algorithm with two deep learning classifiers, deep neural network and deep belief network, and a previously presented hidden Markov model classifier. The study showed that …

Chelator-Free Radiolabeling Of Serrs Nanoparticles For Whole-Body Pet And Intraoperative Raman Imaging, Matthew A. Wall, Travis Shaffer, Stefan Harmsen, Darjus-Felix Tschaharganeh, Chun-Hao Huang, Scott W. Lowe, Charles Michael Drain, Moritz F. Kircher

Publications and Research

A single contrast agent that offers whole-body non-invasive imaging along with the superior sensitivity and spatial resolution of surface-enhanced resonance Raman scattering (SERRS) imaging would allow both pre-operative mapping and intraoperative imaging and thus be highly desirable. We hypothesized that labeling our recently reported ultrabright SERRS nanoparticles with a suitable radiotracer would enable pre-operative identification of regions of interest with whole body imaging that can be rapidly corroborated with a Raman imaging device or handheld Raman scanner in order to provide high precision guidance during surgical procedures. Here we present a straightforward new method that produces radiolabeled SERRS nanoparticles for …

Sensitivity Of Diffuse Reflectance Spectroscopy To Dose- And Depth-Dependent Changes In Tumor Oxygenation After Radiation Therapy, Daria Semeniak

Graduate Theses and Dissertations

Along with chemotherapy, immunotherapy, and surgery, radiotherapy is one of the most common treatments used against cancer. Around 50% of all cancer patients undergo radiation therapy. While for some patients radiotherapy works efficiently and lead to a complete cancer disappearance, for others treatment outcome may be less favorable due to radioresistance processes happening within a tumor on the molecular level. Radioresistance remains a big challenge for modern oncology. The ability to identify radioresistance at the early stage of radiotherapy would help physicians to improve therapy efficiency. At the current moment, despite the rapid progress in cancer understanding and diagnostic modalities, …

Bssfp Elliptical Signal Model With Grappa Parallel Imaging, Grayson Tarbox, Joseph Valentine, Meredith Taylor, Neal Bangerter

Biomedical Engineering Western Regional Conference

In magnetic resonance imaging, balanced steady-state free precession acquisition using the elliptical signal model geometrical solution can be combined with a GRAPPA parallel imaging reconstruction that preserves phase information to shorten scan times.

Validation, Optimization, And Image Processing Of Spiral Cine Dense Magnetic Resonance Imaging For The Quantification Of Left And Right Ventricular Mechanics, Gregory J. Wehner

Theses and Dissertations--Biomedical Engineering

Recent evidence suggests that cardiac mechanics (e.g. cardiac strains) are better measures of heart function compared to common clinical metrics like ejection fraction. However, commonly-used parameters of cardiac mechanics remain limited to just a few measurements averaged over the whole left ventricle. We hypothesized that recent advances in cardiac magnetic resonance imaging (MRI) could be extended to provide measures of cardiac mechanics throughout the left and right ventricles (LV and RV, respectively).

Displacement Encoding with Stimulated Echoes (DENSE) is a cardiac MRI technique that has been validated for measuring LV mechanics at a magnetic field strength of 1.5 T but …

Mammogram And Tomosynthesis Classification Using Convolutional Neural Networks, Xiaofei Zhang

Theses and Dissertations--Computer Science

Mammography is the most widely used method of screening for breast cancer. Traditional mammography produces two-dimensional X-ray images, while advanced tomosynthesis mammography produces reconstructed three-dimensional images. Due to high variability in tumor size and shape, and the low signal-to-noise ratio inherent to mammography, manual classification yields a significant number of false positives, thereby contributing to an unnecessarily large number of biopsies performed to reduce the risk of misdiagnosis. Achieving high diagnostic accuracy requires expertise acquired over many years of experience as a radiologist.

The convolutional neural network (CNN) is a popular deep-learning construct used in image classification. The convolutional process …

Properties And Optimization Of Respiratory Navigator Gating For Spiral Cine Dense Cardiac Mri, Sean Michael Hamlet

Theses and Dissertations--Electrical and Computer Engineering

Cardiac magnetic resonance (MR) imaging can non-invasively assess heart function. Displacement encoding with stimulated echoes (DENSE) is an advanced cardiac MR imaging technique that measures tissue displacement and can be used to quantify cardiac mechanics (e.g. strain and torsion). When combined with clinical risk factors, cardiac mechanics have been shown to be better predictors of mortality than traditional measures of heart function.

End-expiratory breath-holds are typically used to minimize respiratory motion artifacts. Unfortunately, requiring subjects to breath-hold introduces limitations with the duration of image acquisition and quality of data acquired, especially in patients with limited ability to hold their breath. …

From Gd2o3suspension To Nanocomposite: Synthesis, Properties And Radiation Protection, Ly B. T. La

Theses: Doctorates and Masters

This study provides details for the design, preparation of an environmentally friendly, clinically safe and lightweight radiation protective shield made ofGd2O3/epoxy nanocomposite (Gd-nanocomposite) which is proposed as an alternative to traditional toxic lead (Pb)-based aprons for diagnostic X-ray protection. In theory, this particulate nanocomposite can possess significant features of both inorganic particles and organic polymeric matrices. However, in practice, its performance does not simply depend on the sum of the individual contributions of characteristics of the constituent phases but on the interaction of their inner interfaces and the homogeneous dispersion of inorganic particles in the polymer matrix.

The miniaturization of …

Long-Term Biocompatibility, Imaging Appearance And Tissue Effects Associated With Delivery Of A Novel Radiopaque Embolization Bead For Image-Guided Therapy, Karun Sharma, Zainab Bascal, Hugh Kilpatrick, Koorosh Ashrafi, Sean L. Willis, Matthew R. Dreher, Andrew L. Lewis

Pediatrics Faculty Publications

The objective of this study was to undertake a comprehensive long-term biocompatibility and imaging assessment of a new intrinsically radiopaque bead (LC Bead LUMI™) for use in transarterial embolization. The sterilized device and its extracts were subjected to the raft of ISO10993 biocompatibility tests that demonstrated safety with respect to cytotoxicity, mutagenicity, blood contact, irritation, sensitization, systemic toxicity and tissue reaction. Intra-arterial administration was performed in a swine model of hepatic arterial embolization in which 0.22–1 mL of sedimented bead volume was administered to the targeted lobe(s) of the liver. The beads could be visualized during the embolization procedure with …

Diffuse Optical Measurements Of Head And Neck Tumor Hemodynamics For Early Prediction Of Chemoradiation Therapy Outcomes, Lixin Dong, Mahesh Kudrimoti, Daniel Irwin, Li Chen, Sameera Kumar, Yu Shang, Chong Huang, Ellis L. Johnson, Scott D. Stevens, Brent J. Shelton, Guoqiang Yu

Biomedical Engineering Faculty Publications

This study used a hybrid near-infrared diffuse optical instrument to monitor tumor hemodynamic responses to chemoradiation therapy for early prediction of treatment outcomes in patients with head and neck cancer. Forty-seven patients were measured once per week to evaluate the hemodynamic status of clinically involved cervical lymph nodes as surrogates for the primary tumor response. Patients were classified into two groups: complete response (CR) (n = 29) and incomplete response (IR) (n = 18). Tumor hemodynamic responses were found to be associated with clinical outcomes (CR/IR), wherein the associations differed depending on human papillomavirus (HPV-16) status. In HPV-16 …

Portable, Parallel 9-Wavelength Near-Infrared Spectral Tomography (Nirst) System For Efficient Characterization Of Breast Cancer Within The Clinical Oncology Infusion Suite, Yan Zhao, Brian W. Pogue, Steffen J. Haider, Jiang Gui, Roberta Diflorio-Alexander, Keith Paulsen, Shudong Jiang

Dartmouth Scholarship

A portable near-infrared spectral tomography (NIRST) system was developed with simultaneous frequency domain (FD) and continuous-wave (CW) optical measurements for efficient characterization of breast cancer in a clinical oncology setting. Simultaneous FD and CW recordings were implemented to speed up acquisition to 3 minutes for all 9 wavelengths, spanning a range from 661nm to 1064nm. An adjustable interface was designed to fit various breast sizes and shapes. Spatial images of oxy- and deoxy-hemoglobin, water, lipid, and scattering components were reconstructed using a 2D FEM approach. The system was tested on a group of 10 normal subjects, who were examined bilaterally …

A Study On Automated Process For Extracting White Blood Cellular Data From Microscopic Digital Injured Skeletal Muscle Images, Bibek Karki

UNLV Theses, Dissertations, Professional Papers, and Capstones

Skeletal muscle injury is one of the common injuries caused by high-intensity sports activities, military related works, and natural disasters. In order to discover better therapies, it is important to study muscle regeneration process. Muscle regeneration process tracking is the act of monitoring injured tissue section over time, noting white blood cell behavior and cell-fiber relations. A large number of microscopic images are taken for tracking muscle regeneration process over multiple time instances. Currently, manual approach is widely used to analyze a microscopic image of muscle cross section, which is time consuming, tedious and buggy.

Automation of this research methodology …

The Connectivity Domain: Analyzing Resting State Fmri Data Using Feature-Based Data-Driven And Model-Based Methods, Armin Iraji, Vince D. Calhoun, Natalie M. Wiseman, Esmaeil Davoodi-Bojd, Mohammad R. N. Avanaki, Zhifeng Kou

Biomedical Engineering Faculty Research Publications

Spontaneous fluctuations of resting state functional MRI (rsfMRI) have been widely used to understand the macro-connectome of the human brain. However, these fluctuations are not synchronized among subjects, which leads to limitations and makes utilization of first-level model-based methods challenging. Considering this limitation of rsfMRI data in the time domain, we propose to transfer the spatiotemporal information of the rsfMRI data to another domain, the connectivity domain, in which each value represents the same effect across subjects. Using a set of seed networks and a connectivity index to calculate the functional connectivity for each seed network, we transform data into …

Mri Signal Intensity Differentiation Of Brainstem Encephalitis Induced By Enterovirus 71: A Classification Approach For Acute And Convalescence Stages, Hongwu Zeng, Wenxian Huang, Feiqiu Wen, Yonker Wang, Yungen Gan, Weibin Zeng, Ranran Chen, Yanxia He, Zaiyi Liu, Changhong Liang, Kelvin K. L. Wong

Radiology Faculty Publications

Background: The objective of this study is to assess standardized histograms of signal intensities of T1 signal and T2 signal on sagittal view without enhancement during (1) acute stage, and (2) convalescence stage of pediatric patients with Enterovirus 71 related brainstem encephalitis (BE), and with respect to (3) healthy normal.

Methods: Our subjects were hospitalized between March 2010 and October 2012, and underwent pre- and post-contrast MRI studies. The research question to be answered is whether the comparison of the MRI image intensity histograms and relevant statistical quantification can add new knowledge to the diagnosis of BE patients. So, both …

X-Ray Protection, Surface Chemistry And Rheology Of Ball-Milled Submicron Gd2o3 Aqueous Suspension, Ly B. T. La, Yee-Kwong Leong, Christopher Leatherday, Pek I. Au, Kevin Hayward, Laichang Zhang

Research outputs 2014 to 2021

X-ray protective garments are typically comprised of lead-based materials, which are toxic to both people and the environment. Developing alternative lightweight radiation shielding materials is a priority for protecting people working with radiation. Gadolinium, with an electron configuration typical of radiation shielding elements, is proposed as a non-toxic replacement for lead. This study provides new insights into the potential for a gadolinium suspension for replacing lead and proposes an inexpensive and effective preparation method. Submicron gadolinium oxide (Gd₂O₃) was generated using a cost effective ball milling method involving addition of NaCl. Then, the dispersed-flocculated behaviour of …

Voxel-Level Absorbed Dose Calculations With A Deterministic Grid-Based Boltzmann Solver For Nuclear Medicine And The Clinical Value Of Voxel-Level Calculations, Justin Mikell

Dissertations and Theses (Open Access)

Voxel-level absorbed dose (VLAD) is rarely calculated for nuclear medicine (NM) procedures involving unsealed sources or 90Y microspheres (YM). The current standard of practice for absorbed dose calculations in NM utilizes MIRD S-values, which 1) assume a uniform distribution in organs, 2) do not use patient specific geometry, and 3) lack a tumor model. VLADs overcome these limitations. One reason VLADs are not routinely performed is the difficulty in obtaining accurate absorbed doses in a clinically acceptable time. The deterministic grid-based Boltzmann solver (GBBS) was recently applied to radiation oncology where it was reported as fast and accurate for both …

Feasibility Of Using Raman-Based Techniques For Breast Cancer Detection, Sara Mollamohammada

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Breast cancer is one of the common types of cancer among women all over the world. Early diagnosis is an effective way that improve the treatment process and gives the patients a better chance of survival. Many of the patients infected by breast cancer choose breast conservation surgery (BCS). However, some of those will be subjected to mastectomy, and many will have tumor recurrence as there is no precise technique to show the tumor margins. Raman-based methods are powerful techniques with potential to rapidly differentiate normal from tumor tissues and provides a solution to detect tumor margin. This is because …

Calibration And Optimization Of 3d Digital Breast Tomosynthesis Guided Near Infrared Spectral Tomography, Kelly E. Michaelsen, Venkataramanan Krishnaswamy, Linxi Shi, Srinivasan Vedantham, Steven Poplack, Andrew Karellas, Brian Pogue, Keith Paulsen

Dartmouth Scholarship

Calibration of a three-dimensional multimodal digital breast tomosynthesis (DBT) x-ray and non-fiber based near infrared spectral tomography (NIRST) system is challenging but essential for clinical studies. Phantom imaging results yielded linear contrast recovery of total hemoglobin (HbT) concentration for cylindrical inclusions of 15 mm, 10 mm and 7 mm with a 3.5% decrease in the HbT estimate for each 1 cm increase in inclusion depth. A clinical exam of a patient's breast containing both benign and malignant lesions was successfully imaged, with greater HbT was found in the malignancy relative to the benign abnormality and fibroglandular regions (11 μM vs. …

Characterization Of Low Density Intracranial Lesions Using Dual-Energy Computed To Mography, Jessica L. Nute

Dissertations and Theses (Open Access)

Calcific and hemorrhagic foci of susceptibility are frequently encountered on routine brain MR studies. Both etiologies cause variations in local magnetic field strength, leading to dark regions on the MR images that cannot be classified. Single-energy CT (SECT) can be used to identify lesions with attenuation over 100 HU as calcific, however lesions with lower attenuation cannot be reliably identified. While calcific lesions are unlikely to cause harm, hemorrhagic lesions carry a risk of subsequent intracranial bleeding; as such, identification of hemorrhage is vital in preventing the inappropriate use of anticoagulant medications in patients with hemorrhagic lesions.

Given there currently …

Computer Aided Detection Of Oral Lesions On Ct Images, Shaikat Mahmood Galib

Masters Theses

"Oral lesions are important findings on computed tomography images. They are difficult to detect on CT images because of low contrast, arbitrary orientation of objects, complicated topology and lack of clear lines indicating lesions. In this thesis, a fully automatic method to detect oral lesions from dental CT images is proposed to identify (1) Closed boundary lesions and (2) Bone deformation lesions. Two algorithms were developed to recognize these two types of lesions, which cover most of the lesion types that can be found on CT images. The results were validated using a dataset of 52 patients. Using non training …

Computer Aided Diagnosis Of Oral Cancer: Using Time-Step Ct Images, Jonathan T. Scott

Masters Theses

"In medical imaging it is a very common practice to use a technique known as Time-Step imaging in patients who might develop cancer. Time-Step imaging it a very powerful technique, however it can lead to unmanageable amounts of image data. Previously the only way to search all of this data was to manually look through all of the files. This had to be done by trained professionals who knew what to look for within the images and make a judgment about the patient based on the images. This paper discusses the development of an algorithm to have a computer search …

The Multimodal Brain Tumor Image Segmentation Benchmark (Brats), Bjoern H. Menze, Andras Jakab, Stefan Bauer, Jayashree Kalpathy-Cramer, Khan M. Iftekharuddin, Syed M.S. Reza

Electrical & Computer Engineering Faculty Publications

In this paper we report the set-up and results of the Multimodal Brain Tumor Image Segmentation Benchmark (BRATS) organized in conjunction with the MICCAI 2012 and 2013 conferences. Twenty state-of-the-art tumor segmentation algorithms were applied to a set of 65 multi-contrast MR scans of low-and high-grade glioma patients-manually annotated by up to four raters-and to 65 comparable scans generated using tumor image simulation software. Quantitative evaluations revealed considerable disagreement between the human raters in segmenting various tumor sub-regions (Dice scores in the range 74%-85%), illustrating the difficulty of this task. We found that different algorithms worked best for different sub-regions …

Shape/Image Registration For Medical Imaging : Novel Algorithms And Applications., Ahmed Magdy Shalaby 1982-

Electronic Theses and Dissertations

This dissertation looks at two different categories of the registration approaches: Shape registration, and Image registration. It also considers the applications of these approaches into the medical imaging field. Shape registration is an important problem in computer vision, computer graphics and medical imaging. It has been handled in different manners in many applications like shapebased segmentation, shape recognition, and tracking. Image registration is the process of overlaying two or more images of the same scene taken at different times, from different viewpoints, and/or by different sensors. Many image processing applications like remote sensing, fusion of medical images, and computer-aided surgery …

Sensitivity Of Mri-Guided Near-Infrared Spectroscopy Clinical Breast Exam Data And Its Impact On Diagnostic Performance, Michael A. Mastanduno, Junqing Xu, Fadi El-Ghussein, Shudong Jiang, Hong Yin, Yan Zhao, Kelly E. Michaelson, Ke Wang, Fang Ren, Brian W. Pogue, Keith D. Paulsen

Dartmouth Scholarship

In this study, data from breast MRI-guided near infrared spectroscopy (NIRS) exams delivered to 44 patients scheduled for surgical resection (ending in 16 benign and 28 malignant diagnoses) were analyzed using a spatial sensitivity metric to quantify the adequacy of the optical measurements for interrogating the tumor region of interest, as derived from the concurrent MRI scan. Along with positional sensitivity, the incorporation of spectral priors and the selection of an appropriate regularization parameter in the image reconstruction were considered, and found to influence the diagnostic accuracy of the recovered images. Once optimized, the MRI/NIRS data was able to differentiate …