David Mummy

Journal Article Magn Reson Med · April 2024 PURPOSE: The interaction between 129 Xe atoms and pulmonary capillary red blood cells provides cardiogenic signal oscillations that display sensitivity to precapillary and postcapillary pulmonary hypertension. Recently, such oscillations have been spatiall ... Full text Link to item Cite

Cluster Analysis to Identify Long COVID Phenotypes Using 129Xe Magnetic Resonance Imaging: A Multi-centre Evaluation.

Journal Article Eur Respir J · February 8, 2024 BACKGROUND: Long COVID impacts ∼10% of people diagnosed with COVID-19, yet the pathophysiology driving ongoing symptoms is poorly understood. We hypothesised that 129Xe magnetic resonance imaging (MRI) could identify unique pulmonary phenotypic subgroups o ... Full text Link to item Cite

Functional gas exchange measures on 129Xe MRI and spectroscopy are associated with age, sex, and BMI in healthy subjects.

Journal Article Front Med (Lausanne) · 2024 INTRODUCTION: Hyperpolarized 129Xe MRI and spectroscopy is a rapidly growing technique for assessing lung function, with applications in a wide range of obstructive, restrictive, and pulmonary vascular disease. However, normal variations in 129Xe measures ... Full text Link to item Cite

Hyperpolarized 129Xe MRI and spectroscopy of gas exchange abnormalities in chronic hypersensitivity pneumonitis.

Journal Article Respir Med · 2024 PURPOSE: To evaluate 3D gas-exchange functional imaging characteristics using 129Xe MRI in a group of study participants with chronic hypersensitivity pneumonitis (CHP) as compared with healthy control participants. METHODS: In this prospective study, 11 p ... Full text Link to item Cite

Combining neural networks and image synthesis to enable automatic thoracic cavity segmentation of hyperpolarized 129Xe MRI without proton scans.

Journal Article Magn Reson Imaging · November 2023 RATIONALE AND OBJECTIVES: Quantification of 129Xe MRI relies on accurate segmentation of the thoracic cavity, typically performed manually using a combination of 1H and 129Xe scans. This can be accelerated by using Convolutional Neural Networks (CNNs) that ... Full text Link to item Cite

Establishing a hemoglobin adjustment for 129 Xe gas exchange MRI and MRS.

Journal Article Magn Reson Med · October 2023 PURPOSE: 129 Xe MRI and MRS signals from airspaces, membrane tissues (M), and red blood cells (RBCs) provide measurements of pulmonary gas exchange. However, 129 Xe MRI/MRS studies have yet to account for hemoglobin concentration (Hb), which is expected to ... Full text Link to item Cite

Monitoring and Management of Respiratory Function in Pompe Disease: Current Perspectives.

Journal Article Ther Clin Risk Manag · 2023 Pompe disease (PD) is a neuromuscular disorder caused by a deficiency of acid alpha-glucosidase (GAA) - a lysosomal enzyme responsible for hydrolyzing glycogen. GAA deficiency leads to accumulation of glycogen in lysosomes, causing cellular disruption. The ... Full text Link to item Cite

Comparison of hyperpolarized ³He-MRI, CT based parametric response mapping, and mucus scores in asthmatics

Journal Article Frontiers in Physiology · January 1, 2023 Purpose: The purpose of this study was to anatomically correlate ventilation defects with regions of air trapping by whole lung, lung lobe, and airway segment in the context of airway mucus plugging in asthma. Methods: A total of 34 asthmatics [13M:21F, 13 ... Full text Cite

Bias field correction in hyperpolarized ¹²⁹ Xe ventilation MRI using templates derived by RF-depolarization mapping.

Journal Article Magnetic resonance in medicine · August 2022 PurposeTo correct for RF inhomogeneity for in vivo 129 Xe ventilation MRI using flip-angle mapping enabled by randomized 3D radial acquisitions. To extend this RF-depolarization mapping approach to create a flip-angle map template appli ... Full text Cite

Mucus Plugs in Asthma at CT Associated with Regional Ventilation Defects at ³He MRI.

Journal Article Radiology · April 2022 Background Airway mucus plugs in asthma are associated with exacerbation frequency, increased eosinophilia, and reduced lung function. The relationship between mucus plugs and spatially overlapping ventilation abnormalities observed at hyperpolarized gas M ... Full text Cite

Hyperpolarized 129Xe MRI and Spectroscopy of Gas-Exchange Abnormalities in Nonspecific Interstitial Pneumonia.

Journal Article Radiology · October 2021 Background Recent studies demonstrate that antifibrotic drugs previously reserved for idiopathic pulmonary fibrosis (IPF) may slow progression in other interstitial lung diseases (ILDs), creating an urgent need for tools that can sensitively assess disease ... Full text Link to item Cite

Regional Gas Exchange Measured by ¹²⁹ Xe Magnetic Resonance Imaging Before and After Combination Bronchodilators Treatment in Chronic Obstructive Pulmonary Disease.

Journal Article Journal of magnetic resonance imaging : JMRI · September 2021 BackgroundHyperpolarized 129 Xe magnetic resonance imaging (MRI) provides a non-invasive assessment of regional pulmonary gas exchange function. This technique has demonstrated that chronic obstructive pulmonary disease (COPD) patients ... Full text Open Access Cite

Using hyperpolarized 129Xe gas-exchange MRI to model the regional airspace, membrane, and capillary contributions to diffusing capacity.

Journal Article J Appl Physiol (1985) · May 1, 2021 Hyperpolarized 129Xe MRI has emerged as a novel means to evaluate pulmonary function via 3D mapping of ventilation, interstitial barrier uptake, and RBC transfer. However, the physiological interpretation of these measurements has yet to be firmly establis ... Full text Link to item Cite

Ventilation defects on hyperpolarized helium-3 MRI in asthma are predictive of 2-year exacerbation frequency.

Journal Article J Allergy Clin Immunol · October 2020 BACKGROUND: There is an unmet need for an objective biomarker to predict asthma exacerbations. OBJECTIVE: Our aim was to assess the ventilation defect percent (VDP) on hyperpolarized helium-3 magnetic resonance imaging as a predictor of exacerbation freque ... Full text Link to item Cite

Transverse relaxation rates of pulmonary dissolved-phase Hyperpolarized 129 Xe as a biomarker of lung injury in idiopathic pulmonary fibrosis.

Journal Article Magn Reson Med · October 2020 PURPOSE: The MR properties (chemical shifts and R2∗ decay rates) of dissolved-phase hyperpolarized (HP) 129 Xe are confounded by the large magnetic field inhomogeneity present in the lung. This work improves measurements of these properties using a model-b ... Full text Link to item Cite

Illuminating Lung Inflammation at the Alveolar Capillary Interface.

Journal Article J Magn Reson Imaging · June 2020 Full text Link to item Cite

Patient-specific modeling of aerosol delivery in healthy and asthmatic adults.

Journal Article J Appl Physiol (1985) · December 1, 2019 The magnitude and regional heterogeneity of airway obstructions in severe asthmatics is likely linked to insufficient drug delivery, as evidenced by the inability to mitigate exacerbations with inhaled aerosol medications. To understand the correlation bet ... Full text Link to item Cite

Patient-Specific Computational Simulations of Hyperpolarized 3He MRI Ventilation Defects in Healthy and Asthmatic Subjects.

Journal Article IEEE Trans Biomed Eng · October 1, 2018 UNLABELLED: Combined, medical imaging data and respiratory computer simulations may facilitate novel insight into pulmonary disease phenotypes, including the structure/function relationships within the airways. This integration may ultimately enable improv ... Full text Link to item Cite

Ventilation defect percent in helium-3 magnetic resonance imaging as a biomarker of severe outcomes in asthma.

Journal Article J Allergy Clin Immunol · March 2018 Ventilation defect percent (VDP) measured in asthmatics with hyperpolarized helium-3 MRI was more strongly associated with ED visits and hospitalizations due to asthma exacerbation than were conventional biomarkers of lung function and inflammation. ... Full text Link to item Cite

Regional Heterogeneity of Lobar Ventilation in Asthma Using Hyperpolarized Helium-3 MRI.

Journal Article Acad Radiol · February 2018 RATIONALE AND OBJECTIVES: To determine lobar ventilation patterns in asthmatic lungs with hyperpolarized 3He magnetic resonance imaging (HP 3He MRI). MATERIALS AND METHODS: Eighty-two subjects (14 normal, 48 mild-to-moderate asthma, and 20 severe asthma) u ... Full text Link to item Cite

Asthma

Chapter · January 1, 2018 Asthma is a disease with significant clinical impact and growing incidence, particularly in children. It is characterized by a complex interplay of environmental and genetic factors that affect airway structure and function, leading to recurrent and spatia ... Full text Cite

Magnetic resonance imaging with hyperpolarized agents: methods and applications.

Journal Article Phys Med Biol · July 7, 2017 In the past decade, hyperpolarized (HP) contrast agents have been under active development for MRI applications to address the twin challenges of functional and quantitative imaging. Both HP helium (3He) and xenon (129Xe) gases have reached the stage where ... Full text Link to item Cite

Hyperpolarized Gas MRI of the Lung in Asthma

Chapter · January 1, 2017 This chapter explores the application of magnetic resonance imaging (MRI) to the study of asthma with an emphasis on the role of hyperpolarized (HP) gases. Asthma affects millions of people worldwide and trends indicate increasing incidence particularly am ... Full text Cite

Semiautomated Ventilation Defect Quantification in Exercise-induced Bronchoconstriction Using Hyperpolarized Helium-3 Magnetic Resonance Imaging: A Repeatability Study.

Journal Article Acad Radiol · September 2016 RATIONALE AND OBJECTIVES: This study aimed to compare the performance of a semiautomated ventilation defect segmentation approach, adaptive K-means, with manual segmentation of hyperpolarized helium-3 magnetic resonance imaging in subjects with exercise-in ... Full text Link to item Cite

Tumor marker usage and medical care costs among older early-stage breast cancer survivors.

Journal Article J Clin Oncol · January 10, 2015 PURPOSE: Although American Society of Clinical Oncology guidelines discourage the use of tumor marker assessment for routine surveillance in nonmetastatic breast cancer, their use in practice is uncertain. Our objective was to determine use of tumor marker ... Full text Link to item Cite

Survival and lifetime costs associated with first-line bevacizumab use in older patients with metastatic colorectal cancer.

Journal Article Oncologist · August 2014 INTRODUCTION: The objective of this study was to investigate clinical effectiveness and incremental lifetime costs associated with first-line bevacizumab in older patients with metastatic colorectal cancer (mCRC). METHODS: Patients diagnosed with mCRC in 2 ... Full text Link to item Cite

Access to the Indian health service care system is not associated with early enrollment in medicaid for American Indian and Alaska Natives with cancer.

Journal Article Cancer Epidemiol Biomarkers Prev · February 2014 BACKGROUND: For uninsured American Indians and Alaskan Natives (AIAN) diagnosed with cancer, prompt enrollment in Medicaid may speed access to treatment and improve survival. We hypothesized that AIANs who were eligible for the Indian Health Service Care S ... Full text Link to item Cite

Adverse events associated with bevacizumab and chemotherapy in older patients with metastatic colorectal cancer.

Journal Article Clin Colorectal Cancer · September 2013 BACKGROUND: The safety of bevacizumab in older mCRC patients is poorly understood. The purpose of this analysis was to determine the prevalence, incidence, and risk factors for treatment-related AEs in older bevacizumab recipients. PATIENTS AND METHODS: Pa ... Full text Link to item Cite

Referral and treatment patterns among patients with stages III and IV non-small-cell lung cancer.

Journal Article J Oncol Pract · January 2013 PURPOSE: Little is known about how referrals to different cancer specialists influence cancer care for non-small-cell lung cancer (NSCLC). Among Medicare enrollees, we identified factors of patients and their primary care physician that were associated wit ... Full text Link to item Cite

Lung cancer screening with low-dose computed tomography: costs, national expenditures, and cost-effectiveness.

Journal Article J Natl Compr Canc Netw · February 2012 A recent randomized trial showed that low-dose CT (LDCT) screening reduces lung cancer mortality. Health care providers need an assessment of the national budget impact and cost-effectiveness of LDCT screening before this intervention is adopted in practic ... Full text Link to item Cite