Journal ArticleRespir Med · October 5, 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 ...
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Journal ArticleInt J Radiat Oncol Biol Phys · September 1, 2024
PURPOSE: Radiation-induced lung injury has been shown to alter regional ventilation and perfusion in the lung. However, changes in regional pulmonary gas exchange have not previously been measured. METHODS AND MATERIALS: Ten patients receiving conventional ...
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Journal ArticleMagn 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 ...
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Journal ArticleEur 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 ...
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Journal ArticleFront 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 ...
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Journal ArticleMagn 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 ...
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Journal ArticleMagn 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 ...
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Journal ArticleAnn Am Thorac Soc · February 2023
Multiple thoracic imaging modalities have been developed to link structure to function in the diagnosis and monitoring of lung disease. Volumetric computed tomography (CT) renders three-dimensional maps of lung structures and may be combined with positron ...
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Journal ArticlePhys Imaging Radiat Oncol · January 2023
BACKGROUND AND PURPOSE: The accuracy and precision of radiation therapy are dependent on the characterization of organ-at-risk and target motion. This work aims to demonstrate a 4D magnetic resonance imaging (MRI) method for improving spatial and temporal ...
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Journal ArticleTher 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 ...
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Journal ArticleRadiology · November 2022
BACKGROUND: In patients with post-acute COVID-19 syndrome (PACS), abnormal gas-transfer and pulmonary vascular density have been reported, but such findings have not been related to each other or to symptoms and exercise limitation. The pathophysiologic dr ...
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Journal ArticleRadiol Clin North Am · November 2022
Patients with diffuse lung diseases require thorough medical and social history and physical examinations, coupled with a multitude of laboratory tests, pulmonary function tests, and radiologic imaging to discern and manage the specific disease. This revie ...
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Journal ArticleJ Magn Reson Imaging · October 2022
BACKGROUND: 129 Xe gas-transfer MRI provides regional measures of pulmonary gas exchange in adults and separates xenon in interstitial lung tissue/plasma (barrier) from xenon in red blood cells (RBCs). The technique has yet to be demonstrated in pediatric ...
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Journal ArticleMagn Reson Med · August 2022
PURPOSE: To 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 applicable to arbitrary ...
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ConferenceERJ Open Res · April 2022
BACKGROUND: The diagnosis of pulmonary hypertension (PH) remains challenging. Pre- and post-capillary PH have different signatures on noninvasive 129Xe gas-exchange magnetic resonance imaging (MRI) and dynamic MR spectroscopy (MRS). We tested the accuracy ...
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Journal ArticleMagn Reson Med · March 2022
PURPOSE: To reduce scan duration in hyperpolarized 129 Xe 1-point Dixon gas exchange imaging by utilizing flip angle (FA)/TR equivalence. METHODS: Images were acquired in 12 subjects (n = 3 radiation therapy, n = 1 unexplained dyspnea, n = 8 healthy) using ...
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Journal ArticleRespirology · February 2022
Pulmonary functional MRI (PfMRI) using inhaled hyperpolarized, radiation-free gases (such as 3 He and 129 Xe) provides a way to directly visualize inhaled gas distribution and ventilation defects (or ventilation heterogeneity) in real time with high spatia ...
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Journal ArticleMagn Reson Med · December 2021
Hyperpolarized (HP) 129 Xe MRI uniquely images pulmonary ventilation, gas exchange, and terminal airway morphology rapidly and safely, providing novel information not possible using conventional imaging modalities or pulmonary function tests. As such, ther ...
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Journal ArticleInt J Radiat Oncol Biol Phys · November 15, 2021
PURPOSE: To present a methodology to use pulmonary gas exchange maps to guide functional avoidance treatment planning in radiation therapy (RT) and evaluate its efficacy compared with ventilation-guided treatment planning. METHODS AND MATERIALS: Before rec ...
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Journal ArticleRadiology · 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 ...
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Journal ArticleJ Magn Reson Imaging · September 2021
BACKGROUND: Hyperpolarized 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 exhibit ventilatio ...
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Journal ArticleJ 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 ...
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Journal ArticleTher Adv Chronic Dis · 2021
Imaging modalities such as plain chest radiograph and computed tomography (CT) are important tools in the assessment of patients with chronic obstructive pulmonary disease (COPD) of any etiology. These methods facilitate differential diagnoses and the asse ...
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Journal ArticleAcad Radiol · August 2020
RATIONALE: Hyperpolarized 129Xe ventilation MRI is typically acquired using multislice fast gradient recalled echo (GRE), but interleaved 3D radial 129Xe gas transfer MRI now provides dissolved-phase and ventilation images from a single breath. To investig ...
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Journal ArticleJ Appl Physiol (1985) · August 1, 2020
Magnetic resonance (MR) imaging and spectroscopy using dissolved hyperpolarized (HP) 129Xe have expanded the ability to probe lung function regionally and noninvasively. In particular, HP 129Xe imaging has been used to quantify impaired gas uptake by the p ...
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Journal ArticleSci Rep · April 30, 2020
Hyperpolarized 129Xe magnetic resonance imaging (MRI) is capable of regional mapping of pulmonary gas-exchange and has found application in a wide range of pulmonary disorders in humans and animal model analogs. This study is the first application of 129Xe ...
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Journal ArticleEur Respir J · December 2019
BACKGROUND: As an increasing number of patients exhibit concomitant cardiac and pulmonary disease, limitations of standard diagnostic criteria are more frequently encountered. Here, we apply noninvasive 129Xe magnetic resonance imaging (MRI) and spectrosco ...
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Journal ArticleMagn Reson Med · November 2019
PURPOSE: Hyperpolarized 129 Xe MR is increasingly being adopted worldwide, but no standards exist for assessing or comparing performance at different 129 Xe imaging centers. Therefore, we sought to develop a thermally polarized xenon phantom assembly, appr ...
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Journal ArticleAcad Radiol · July 2019
RATIONALE: Hyperpolarized 129Xe MRI enables quantitative evaluation of regional ventilation. To this end, multiple classifiers have been proposed to determine ventilation defect percentage (VDP) as well as other cluster populations. However, consensus has ...
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Journal ArticleAJR Am J Roentgenol · April 2019
OBJECTIVE: The objective of our study was to identify the magnitude and distribution of ventilation defect scores (VDSs) derived from hyperpolarized (HP) 129Xe-MRI associated with clinically relevant airway obstruction. MATERIALS AND METHODS: From 2012 to ...
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Journal ArticleJ Med Imaging (Bellingham) · April 2019
Three-dimensional (3D) printing has significantly impacted the quality, efficiency, and reproducibility of preclinical magnetic resonance imaging. It has vastly expanded the ability to produce MR-compatible parts that readily permit customization of animal ...
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Journal ArticleJ Thorac Imaging · March 2019
Idiopathic pulmonary fibrosis (IPF) is a progressive pulmonary disease that is ultimately fatal. Although the diagnosis of IPF has been revolutionized by high-resolution computed tomography, this imaging modality still exhibits significant limitations, par ...
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Journal ArticleNMR Biomed · January 2019
The spectral parameters of hyperpolarized 129 Xe exchanging between airspaces, interstitial barrier, and red blood cells (RBCs) are sensitive to pulmonary pathophysiology. This study sought to evaluate whether the dynamics of 129 Xe spectroscopy provide ad ...
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Journal ArticleMagn Reson Med · December 2018
PURPOSE: Hyperpolarized 129 Xe MRI depicting 3D ventilation, interstitial barrier uptake, and transfer to red blood cells (RBCs) has emerged as a powerful new means of detecting pulmonary disease. However, given the challenging susceptibility environment o ...
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Journal ArticleJ Magn Reson · October 2018
Hyperpolarized (HP) 129Xe MRI is emerging as a powerful, non-invasive method to image lung function and is beginning to find clinical application across a range of conditions. As clinical implementation progresses, it becomes important to translate back to ...
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Journal ArticleInt J Radiat Oncol Biol Phys · August 1, 2018
PURPOSE: To investigate the degree to which lung ventilation and gas exchange are regionally correlated, using the emerging technology of hyperpolarized (HP)-129Xe magnetic resonance imaging (MRI). METHODS AND MATERIALS: Hyperpolarized-129Xe MRI studies we ...
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Journal ArticleJ Med Imaging Radiat Oncol · February 2018
Hyperpolarized 129 Xenon-MRI (HP 129 Xe MRI) is an emerging imaging modality that allows assessment of both ventilation and gas transfer. Most research to date has focused on non-malignant pulmonary diseases. However, the capability of evaluating the two p ...
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Journal ArticleThorax · January 2018
BACKGROUND: Assessing functional impairment, therapeutic response and disease progression in patients with idiopathic pulmonary fibrosis (IPF) continues to be challenging. Hyperpolarized 129Xe MRI can address this gap through its unique capability to image ...
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Journal ArticleMagn Reson Med · October 2017
PURPOSE: The purpose of this work was to accurately characterize the spectral properties of hyperpolarized 129 Xe in patients with idiopathic pulmonary fibrosis (IPF) compared to healthy volunteers. METHODS: Subjects underwent hyperpolarized 129 Xe breath- ...
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Journal ArticleJ Appl Phys · July 14, 2017
High-volume production of hyperpolarized 129Xe by spin-exchange optical pumping (SEOP) has historically fallen short of theoretical predictions. Recently, this shortfall was proposed to be caused by the formation of alkali metal clusters during optical pum ...
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Journal ArticleAm J Transplant · July 2017
Bronchial stenosis in lung transplant recipients is a common disorder that adversely affects clinical outcomes. It is evaluated by spirometry, CT scanning, and bronchoscopy with significant limitations. We hypothesize that MRI using both ultrashort echo ti ...
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Journal ArticleMed Phys · June 2017
PURPOSE: Hyperpolarized 129 Xe magnetic resonance imaging (MRI) using Dixon-based decomposition enables single-breath imaging of 129 Xe in the airspaces, interstitial barrier tissues, and red blood cells (RBCs). However, methods to quantitatively visualize ...
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Journal ArticleMagn Reson Med · April 2017
PURPOSE: 129 Xe interacts with biological media to exhibit chemical shifts exceeding 200 ppm that report on physiology and pathology. Extracting this functional information requires shifts to be measured precisely. Historically, shifts have been reported r ...
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Journal ArticleAm J Physiol Lung Cell Mol Physiol · April 1, 2017
Human genome-wide association studies have identified over 50 loci associated with pulmonary function and related phenotypes, yet follow-up studies to determine causal genes or variants are rare. Single nucleotide polymorphisms in serotonin receptor 4 (HTR ...
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Journal ArticleInvest Radiol · February 2017
OBJECTIVES: The aim of this study was to investigate ventilation in mild to moderate asthmatic patients and age-matched controls using hyperpolarized (HP) Xenon magnetic resonance imaging (MRI) and correlate findings with pulmonary function tests (PFTs). M ...
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Journal ArticleEur J Radiol · January 2017
In the last two decades, functional imaging of the lungs using hyperpolarized noble gases has entered the clinical stage. Both helium (3He) and xenon (129Xe) gas have been thoroughly investigated for their ability to assess both the global and regional pat ...
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Journal ArticleAcad Radiol · December 2016
RATIONALE AND OBJECTIVES: Ventilation heterogeneity is impossible to detect with spirometry. Alternatively, pulmonary ventilation can be imaged three-dimensionally using inhaled 129Xe magnetic resonance imaging (MRI). To date, such images have been quantif ...
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Journal ArticleMed Phys · June 2016
PURPOSE: To describe a novel method for self-sorted 4D-MRI and to characterize the output image quality as measured by signal-to-noise ratio (SNR), spatiotemporal resolution, and level of artifact. METHODS: A three-dimensional radial sampling function with ...
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Journal ArticleMagn Reson Med · April 2016
PURPOSE: We sought to develop and test a clinically feasible 1-point Dixon, three-dimensional (3D) radial acquisition strategy to create isotropic 3D MR images of (129)Xe in the airspaces, barrier, and red blood cells (RBCs) in a single breath. The approac ...
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Journal ArticlePulm Circ · March 2016
The diagnosis of pulmonary vascular disease (PVD) is usually based on hemodynamic and/or clinical criteria. Noninvasive imaging of the heart and proximal vasculature can also provide useful information. An alternate approach to such criteria in the diagnos ...
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Journal ArticleMagn Reson Imaging · September 2015
PURPOSE: The aim of this study was to evaluate the effect of hyperpolarized (129)Xe dose on image signal-to-noise ratio (SNR) and ventilation defect conspicuity on both multi-slice gradient echo and isotropic 3D-radially acquired ventilation MRI. MATERIALS ...
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Journal ArticleConcepts in Magnetic Resonance Part A: Bridging Education and Research · July 1, 2015
The goal of this work is to characterize and optimize gridding reconstruction of 3D radial hyperpolarized (HP) 129Xe MRI. In support of this objective, we developed a flexible, open source reconstruction software package in MATLAB to optimally reconstruct ...
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Journal ArticleMagn Reson Imaging Clin N Am · May 2015
Functional imaging offers information more sensitive to changes in lung structure and function. Hyperpolarized helium ((3)He) and xenon ((129)Xe) MR imaging of the lungs provides sensitive contrast mechanisms to probe changes in pulmonary ventilation, micr ...
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Journal ArticleNMR Biomed · December 2014
A variety of pulmonary pathologies, in particular interstitial lung diseases, are characterized by thickening of the pulmonary blood-gas barrier, and this thickening results in reduced gas exchange. Such diffusive impairment is challenging to quantify spat ...
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Journal ArticleAcad Radiol · December 2014
RATIONALE AND OBJECTIVES: Clinical deployment of hyperpolarized (129)Xe magnetic resonance imaging requires accurate quantification and visualization of the ventilation defect percentage (VDP). Here, we improve the robustness of our previous semiautomated ...
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Journal ArticleJ Appl Physiol (1985) · September 15, 2014
Although xenon is classically taught to be a "perfusion-limited" gas, (129)Xe in its hyperpolarized (HP) form, when detected by magnetic resonance (MR), can probe diffusion limitation. Inhaled HP (129)Xe diffuses across the pulmonary blood-gas barrier, and ...
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Journal ArticlePhys Rev A · August 6, 2014
The ability to produce liter volumes of highly spin-polarized 129Xe enables a wide range of investigations, most notably in the fields of materials science and biomedical MRI. However, for nearly all polarizers built to date, both peak 129Xe polarization a ...
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Journal ArticleMagn Reson Med · November 2013
PURPOSE: Hyperpolarized (HP) (129) Xe gas in the alveoli can be detected separately from (129) Xe dissolved in pulmonary barrier tissues (blood plasma and parenchyma) and red blood cells (RBCs) of humans, allowing this isotope to probe impaired gas uptake. ...
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Journal ArticleJ Appl Physiol (1985) · September 2013
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Although some central aspects of pulmonary function (ventilation and perfusion) are known to be heterogeneous, the distribution of diffusive gas exchange remains poorly characterized. A solution is offered by hyperpolarized 129Xe magnetic resonance (MR) im ...
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Journal ArticleNMR Biomed · April 2013
In this study, hyperpolarized (129) Xe MR ventilation and (1) H anatomical images were obtained from three subject groups: young healthy volunteers (HVs), subjects with chronic obstructive pulmonary disease (COPD) and age-matched controls (AMCs). Ventilati ...
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Journal ArticleILAR Journal · September 11, 2012
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Small animal magnetic resonance microscopy (MRM) has evolved significantly from testing the boundaries of imaging physics to its expanding use today as a tool in noninvasive biomedical investigations. MRM now increasingly provides functional information ab ...
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Journal ArticleRadiology · January 2012
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PURPOSE: To evaluate the safety and tolerability of inhaling multiple 1-L volumes of undiluted hyperpolarized xenon 129 ((129)Xe) followed by up to a 16-second breath hold and magnetic resonance (MR) imaging. MATERIALS AND METHODS: This study was approved ...
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Journal ArticlePLoS One · 2012
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BACKGROUND: Hyperpolarized (HP) (129)Xe magnetic resonance imaging (MRI) permits high resolution, regional visualization of pulmonary ventilation. Additionally, its reasonably high solubility (>10%) and large chemical shift range (>200 ppm) in tissues allo ...
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Journal ArticleJ Magn Reson · September 2011
In magnetic resonance imaging with hyperpolarized (HP) noble gases, data is often acquired during prolonged gas delivery from a storage reservoir. However, little is known about the extent to which relaxation within the reservoir will limit the useful acqu ...
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Journal ArticleAm J Respir Cell Mol Biol · May 2011
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Regions of diminished ventilation are often evident during functional pulmonary imaging studies, including hyperpolarized gas magnetic resonance imaging (MRI), positron emission tomography, and computed tomography (CT). The objective of this study was to c ...
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Journal ArticleMagn Reson Med · April 2011
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Given its greater availability and lower cost, (129) Xe apparent diffusion coefficient (ADC) MRI offers an alternative to (3) He ADC MRI. To demonstrate the feasibility of hyperpolarized (129) Xe ADC MRI, we present results from healthy volunteers (HV), ch ...
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Journal ArticleJ Magn Reson · February 2011
When hyperpolarized noble gases are brought into the bore of a superconducting magnet for magnetic resonance imaging (MRI) or spectroscopy studies, the gases must pass through substantial field gradients, which can cause rapid longitudinal relaxation. In t ...
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Journal ArticlePLoS One · August 16, 2010
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BACKGROUND: One of the central physiological functions of the lungs is to transfer inhaled gases from the alveoli to pulmonary capillary blood. However, current measures of alveolar gas uptake provide only global information and thus lack the sensitivity a ...
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Journal ArticleMagn Reson Med · March 2010
The capability to use high-resolution (3)He MRI to depict regional ventilation changes and airway narrowing in mice challenged with methacholine (MCh) offers the opportunity to gain new insights into the study of asthma. However, to fully exploit the value ...
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Journal ArticleProc Natl Acad Sci U S A · February 23, 2010
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Early and specific detection of metastatic cancer cells in the lung (the most common organ targeted by metastases) could significantly improve cancer treatment outcomes. However, the most widespread lung imaging methods use ionizing radiation and have low ...
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Journal ArticleJ Phys Chem B · September 17, 2009
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Hyperpolarized (HP) (129)Xe yields high signal intensities in nuclear magnetic resonance (NMR) and, through its large chemical shift range of approximately 300 ppm, provides detailed information about the local chemical environment. To exploit these proper ...
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Journal ArticleRadiology · August 2009
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PURPOSE: To develop and demonstrate a method for regional evaluation of pulmonary perfusion and gas exchange based on intravenous injection of hyperpolarized xenon 129 ((129)Xe) and subsequent magnetic resonance (MR) imaging of the gas-phase (129)Xe emergi ...
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Journal ArticleNMR Biomed · June 2009
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Hyperpolarized (HP) (3)He magnetic resonance imaging has been recently used to produce high-resolution images of pulmonary ventilation after methacholine (MCh) challenge in mouse models of allergic inflammation. This capability presents an opportunity to g ...
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Journal ArticleJournal of Applied Physics · November 24, 2008
The production of hyperpolarized gases by spin-exchange optical pumping (SEOP) requires exact knowledge of the alkali metal's D1 absorption profile and the degree to which it is broadened and shifted by varying buffer gas composition and pressure. We have ...
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Journal ArticleMagn Reson Med · July 2008
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MR imaging of hyperpolarized (HP) nuclei is challenging because they are typically delivered in a single dose of nonrenewable magnetization, from which the entire image must be derived. This problem can be overcome with HP (129)Xe, which can be produced su ...
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Journal ArticleILAR J · 2008
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Small animal magnetic resonance microscopy (MRM) has evolved significantly from testing the boundaries of imaging physics to its expanding use today as a tool in noninvasive biomedical investigations. MRM now increasingly provides functional information ab ...
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Journal ArticleMagn Reson Med · November 2007
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In the study of asthma, a vital role is played by mouse models, because knockout or transgenic methods can be used to alter disease pathways and identify therapeutic targets that affect lung function. Assessment of lung function in rodents by available met ...
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Journal ArticleToxicol Pathol · January 2007
In vivo magnetic resonance microscopy (MRM) of the small animal lung has become a valuable research tool, especially for preclinical studies. MRM offers a noninvasive and nondestructive tool for imaging small animals longitudinally and at high spatial reso ...
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Journal ArticleProc Natl Acad Sci U S A · November 28, 2006
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Effective pulmonary gas exchange relies on the free diffusion of gases across the thin tissue barrier separating airspace from the capillary red blood cells (RBCs). Pulmonary pathologies, such as inflammation, fibrosis, and edema, which cause an increased ...
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Journal ArticleMagn Reson Med · June 2005
In this experiment, Sprague-Dawley rats with elastase-induced emphysema were imaged using hyperpolarized (3)He MRI. Regional fractional ventilation r, the fraction of gas replaced with a single tidal breath, was calculated from a series of images in a wash ...
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Journal ArticleAcad Radiol · October 2004
RATIONALE AND OBJECTIVES: The aim of this study was to establish a standardized procedure for the measurement of regional fractional ventilation in a healthy rat model as a baseline for further studies of pulmonary disorder models. MATERIALS AND METHODS: T ...
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Journal ArticleMagn Reson Med · December 2003
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The ability to quantify pulmonary diffusing capacity and perfusion using dynamic hyperpolarized (129)Xe NMR spectroscopy is demonstrated. A model of alveolar gas exchange was developed, which, in conjunction with (129)Xe NMR, enables quantification of aver ...
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Journal ArticlePhys Rev Lett · September 19, 2003
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We demonstrate spin-exchange optical pumping of 3He using a "hybrid" K-Rb vapor mixture. The Rb atoms absorb light from a standard laser at 795 nm, then collisionally polarize the potassium atoms. Spin-exchange collisions of K and 3He atoms then transfer t ...
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Journal ArticleChemical Physics Letters · March 7, 2003
We present a model of 3 He relaxation on the surface of borosilicate glass which accurately predicts observed relaxation rates and their temperature dependence. Above room temperature 3 He dissolves into Pyrex, where interactions with Fe 3+ ions result in ...
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Journal ArticleNMR Biomed · June 2000
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One of the major goals of hyperpolarized-gas MR imaging has been to obtain (129)Xe dissolved-phase images in humans. Since the dissolved-phase signal is much weaker than the gas-phase signal, highly optimized MR pulse sequences are required to obtain adequ ...
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Journal ArticleMagn Reson Med · October 1999
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The transverse relaxation time, T *(2), of hyperpolarized (HP) gas in the lung in vivo is an important parameter for pulse sequence optimization and image contrast. We obtained T *(2) maps of HP (3)He and (129)Xe in guinea pig lungs (n = 17) and in human l ...
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Journal ArticleMagn Reson Med · October 1999
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In imaging of hyperpolarized noble gases, a knowledge of the diffusion coefficient (D) is important both as a contrast mechanism and in the design of pulse sequences. We have made diffusion coefficient maps of both hyperpolarized (3)He and (129)Xe in guine ...
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Journal ArticleJ Magn Reson · August 1999
We have investigated the transfer of polarization from (129)Xe to solute protons in aqueous solutions to determine the feasibility of using hyperpolarized xenon to enhance (1)H sensitivity in aqueous systems at or near room temperatures. Several solutes, e ...
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Journal ArticleMagn Reson Med · May 1999
Hyperpolarized (HP) 129Xe can be dissolved in biologically compatible lipid emulsions while maintaining sufficient polarization for in vivo vascular imaging. For xenon in Intralipid 30%, in vitro spectroscopy at 2 T yielded a chemical shift of 197 +/- 1 pp ...
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Journal ArticleMagn Reson Med · April 1999
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Three-dimensional magnetic resonance images of the guinea pig lung were acquired in vivo using hyperpolarized (HP) noble gases and radial projection encoding (PE). Results obtained with 3He (voxel size 17 microl) demonstrated high image quality showing air ...
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Journal ArticleJ Magn Reson · November 1998
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The nonequilibrium bulk magnetic moment of hyperpolarized (HP) noble gases generated by optical pumping has unique characteristics. Based on the Bloch equations, a model was developed describing the signal dynamics of HP gases used in magnetic resonance im ...
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Journal ArticleMagn Reson Med · July 1997
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The magnetization in hyperpolarized gas (HP) MRI is generated by laser polarization that is independent of the magnet and imaging process. As a consequence, there is no equilibrium magnetization during the image acquisition. The competing processes of gas ...
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Journal ArticleMagn Reson Med · June 1997
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Using a new method of xenon laser-polarization that permits the generation of liter quantities of hyperpolarized 129Xe gas, the first 129Xe imaging results from the human chest and the first 129Xe spectroscopy results from the human chest and head have bee ...
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Journal ArticleApplied Physics Letters · September 16, 1996
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A method is described for producing several liters of nuclear spin polarized 129Xe gas via spin exchange with an optically pumped Rb vapor. We use a 140 W AlGaAs laser diode array whose broad spectral output is efficiently absorbed by employing ∼ 10 atm of ...
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Journal ArticleRadiology · August 1996
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Two healthy volunteers who had inhaled approximately 0.75 L of laser-polarized helium-3 gas underwent magnetic resonance imaging at 1.5 T with fast gradient-echo pulse sequences and small flip angles ( < 10 degrees). Thick-section (20 mm) coronal images, t ...
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Journal ArticleRadiology · June 1996
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The authors imaged the lungs of live guinea pigs with hyperpolarized (HP) helium-3 as a magnetic resonance (MR) signal source. HP He-3 gas produced through spin exchange with rubidium metal vapor was delivered through an MR-compatible, small-animal ventila ...
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Journal ArticleNuclear Inst. and Methods in Physics Research, A · March 1, 1995
A large-scale high-pressure gaseous 3He polarized target has been developed for use with a high-intensity polarized electron beam at the Stanford Linear Accelerator Center. This target was used successfully in an experiment to study the spin structure of t ...
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Journal ArticleNature · July 21, 1994
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As currently implemented, magnetic resonance imaging (MRI) relies on the protons of water molecules in tissue to provide the NMR signal. Protons are, however, notoriously difficult to image in some biological environments of interest, notably the lungs and ...
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Journal ArticlePhysics Letters A · December 27, 1993
We have demonstrated a large polarization transfer from highly polarized gaseous 129Xe to protons in a silicone surface coating. The proton polarization enhancement of ∼ 104-105 over the thermal equilibrium polarization at 0.2 T makes possible the detectio ...
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