A5019251773- Atomic and Subatomic Physics Research
- Advanced NMR Techniques and Applications
- Advanced MRI Techniques and Applications
- Quantum, superfluid, helium dynamics
- Ultrasound and Hyperthermia Applications
- Nuclear Physics and Applications
- Chronic Obstructive Pulmonary Disease (COPD) Research
- Advanced Neuroimaging Techniques and Applications
- Lung Cancer Diagnosis and Treatment
- Cystic Fibrosis Research Advances
- Cardiac Imaging and Diagnostics
- Advanced Radiotherapy Techniques
- Medical Imaging Techniques and Applications
- Effects of Radiation Exposure
- Ultrasound in Clinical Applications
- Thermal Regulation in Medicine
- Radiation Detection and Scintillator Technologies
- Ultrasound Imaging and Elastography
- Medical Imaging and Pathology Studies
- Radiomics and Machine Learning in Medical Imaging
- Superconducting Materials and Applications
- Interstitial Lung Diseases and Idiopathic Pulmonary Fibrosis
- Cerebrospinal fluid and hydrocephalus
- Congenital Diaphragmatic Hernia Studies
- Inorganic Fluorides and Related Compounds
University of Virginia
2016-2025
Johns Hopkins University
2024
National Cancer Institute
2024
Johns Hopkins Medicine
2024
University of Maryland, Baltimore
2024
University of Virginia Health System
2001-2020
Universitat Autònoma de Barcelona
1988
Hospital de Sant Pau
1988
In patients with acute myocardial infarction (MI), delayed enhancement is seen in MRI 5 to 7 minutes after gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA) injection, and the occurs regions that later show recovery of function. However, a canine model MI, 20 30 injection only necrotic not surrounding, reversibly injured myocardium. The objective present study was determine (1) if size enhanced region varies time Gd-DTPA (2) when corresponds true infarct size.The left coronary artery...
Despite a myriad of technical advances in medical imaging, as well the growing need to address global impact pulmonary diseases, such asthma and chronic obstructive disease, on health quality life, it remains challenging obtain vivo regional depiction quantification most basic physiological functions lung—gas delivery airspaces gas uptake by lung parenchyma blood—in manner suitable for routine application humans. We report method based MRI hyperpolarized xenon-129 that permits simultaneous...
Purpose To develop a breathhold acquisition for regional mapping of ventilation and the fractions hyperpolarized xenon‐129 (Xe129) dissolved in tissue (lung parenchyma plasma) red blood cells (RBCs), to perform an exploratory study characterize data obtained human subjects. Materials Methods A three‐dimensional, multi‐echo, radial‐trajectory pulse sequence was developed obtain (gaseous Xe129), tissue, RBC images healthy subjects, smokers, asthmatics. Signal ratios (total Xe129 gas,...
Magnetic‐resonance spectroscopy and imaging using hyperpolarized xenon‐129 show great potential for evaluation of the most important function human lung ‐‐ gas exchange. In particular, chemical shift saturation recovery (CSSR) provides physiological information as a whole by characterizing dynamic process exchange, while dissolved‐phase (DP) captures time‐averaged regional distribution uptake tissue blood. Herein, we present recent advances in assessing CSSR DP total 45 subjects (23 healthy,...
Hyperpolarized (HP) 129 Xe MRI uniquely images pulmonary ventilation, gas exchange, and terminal airway morphology rapidly safely, providing novel information not possible using conventional imaging modalities or function tests. As such, there is mounting interest in expanding the use of biomarkers derived from HP as outcome measures multi-site clinical trials across a range disorders. Until recently, techniques have been developed largely independently at limited number academic centers,...
Abstract Purpose: To develop and test a method to noninvasively assess the functional lung microstructure. Materials Methods: The Multiple exchange time Xenon polarization Transfer Contrast technique (MXTC) encodes xenon gas‐exchange contrast at multiple delay times permitting two lung‐function parameters be derived: (i) MXTC‐F, long exchange‐time depolarization value, which is proportional tissue alveolar‐volume ratio (ii) MXTC‐S, square root of constant, characterizes thickness composition...
Abstract With the use of polarization‐transfer pulse sequences and hyperpolarized 129 Xe NMR, gas exchange in lung can be measured quantitatively. However, harnessing inherently high sensitivity this technique as a tool for exploring function requires fundamental understanding xenon gas‐exchange diffusion processes lung, how these may differ between healthy pathological conditions. Toward goal, we employed NMR spectroscopy imaging techniques animal models to investigate dependence relative...
The apparent diffusion coefficients (ADCs) of hyperpolarized (3)He and (129)Xe gases were measured in the lungs rabbits with elastase-induced emphysema correlated against mean chord length from lung histology. In vivo measurements performed at baseline 2, 4, 6, 8 wk after instillation elastase (mild moderate groups) or saline (control group). ADCs determined acquisitions that used two b values. To investigate effect value on results, b-value pairs 0 1.6 s/cm(2) 4.0 for (3)He, 5.0 10.0...
Abstract Purpose To determine whether hyperpolarized helium‐3 (HHe) diffusion MR can detect the expected enlargement of alveoli that occurs with lung growth during childhood. Materials and Methods A total 29 normal subjects aged four to 30 years underwent HHe imaging b ‐value pair 0, 1.6 second/cm 2 . second acquisition a separate breathhold was performed using 4 evaluate dependence on ‐value. The mean apparent coefficient (ADC) volume for each subject determined. Results Subjects as young...
Abstract Purpose To investigate short‐ and long‐time‐scale 3 He diffusion in asthma. Materials Methods A hybrid MRI sequence was developed to obtain coregistered apparent coefficient (ADC) maps during a single breath‐hold. The study groups were: asthma ( n = 14); healthy chronic obstructive pulmonary disease (COPD) 9). Correlations were made between mean‐ADC %ADC‐abn (abnormal) (%pixels with ADC > mean +2 SD of healthy) at both time scales spirometry. Sensitivities determined using...
ABSTRACT Hyperpolarized gas (HPG) magnetic resonance (MR) imaging allows for the quantification of pulmonary defects with ventilation defect percentage (VDP). Although informative, VDPs lack information regarding spatial distribution defects. We developed a method quantifying focality/sparseness in hyperpolarized‐gas lung MR images. The study involved total 56 subjects: 14 asthmatics (age mean ± sd = 45.1 18.9), 25 COPD subjects 60.6 10.4), and 17 CF 21.8 8.4). analyzed data are from four...
Abstract A pulse‐sequence strategy was developed for generating regional maps of alveolar oxygen partial pressure ( p O 2 ) in a single 6‐sec breath hold, use human subjects with impaired lung function. Like previously described methods, values are obtained by measuring the oxygen‐induced T 1 relaxation inhaled hyperpolarized 3 He. Unlike other only two He images acquired: one reverse‐centric and centric phase‐encoding order. This arrangement minimizes effects flip‐angle variations, so that...
Abstract Hyperpolarized xenon‐129 is a noninvasive contrast agent for lung MRI, which upon inhalation dissolves in parenchymal structures, thus mirroring the gas‐exchange process oxygen lung. Multiple‐exchange‐time xenon polarization transfer (MXTC) MRI an implementation of XTC technique four dimensions (three spatial plus exchange time). The aim this study was to evaluate sensitivity MXTC detection microstructural deformations healthy response gravity‐induced tissue compression and degree...
Purpose To investigate whether chemical shift saturation recovery (CSSR) MR spectroscopy with hyperpolarized xenon‐129 is sensitive to the pulsatile nature of pulmonary blood flow during cardiac cycle. Methods A CSSR pulse sequence typically uses radiofrequency (RF) pulses saturate magnetization dissolved in lung tissue followed, after a variable delay time, by an RF excitation and subsequent acquisition free‐induction decay. Thereby it possible monitor uptake extract physiological...
To develop and evaluate a protocol for hyperpolarized helium-3 (HHe) ventilation magnetic resonance imaging (MRI) of the lungs non-sedated infants children.HHe MRI was performed on seven children ≤4years old. Contiguous 2D-spiral images were acquired sequentially with scan time ≤0.2s/slice.Motion-artifact-free, high signal-to-noise ratio (SNR) lung obtained. Gas homogeneously distributed in healthy individuals; focal defects found patients respiratory diseases.HHe can aid assessment...
Background Apparent diffusion coefficient (ADC) maps of inhaled hyperpolarized gases have shown promise in the characterization emphysema patients with chronic obstructive pulmonary disease (COPD), yet an easily interpreted quantitative metric beyond mean and standard deviation has not been established. Purpose To introduce a framework which to characterize burden based on helium 3 (3He) xenon 129 (129Xe) ADC compare its diagnostic performance CT-based metrics function tests (PFTs)....
To assess the effect of lung volume on measured values and repeatability xenon 129 (
Abstract A new technique is demonstrated in six healthy human subjects that combines grid‐tagging and hyperpolarized helium‐3 MRI to assess regional lung biomechanical function quantitative ventilation. 2D grid‐tagging, achieved by applying sinc‐modulated RF‐pulse trains along the frequency‐ phase‐encoding directions, was followed a multislice fast low‐angle shot (FLASH)‐based acquisition at inspiration expiration. The displacement vectors, first second principal strains, ventilation were...
To investigate whether hyperpolarised xenon-129 MRI (HXeMRI) enables regional and physiological resolution of diffusing capacity limitations in chronic obstructive pulmonary disease (COPD), we evaluated 34 COPD subjects 11 healthy volunteers. We report significant correlations between airflow abnormality quantified by HXeMRI per cent predicted forced expiratory volume 1 s; gas transfer to red blood cells carbon monoxide diffusion (%DLCO); interstitium emphysema multidetector chest CT....
Idiopathic pulmonary fibrosis, a pattern of interstitial lung disease, is often clinically unpredictable in its progression. This paper presents hyperpolarized Xenon-129 chemical shift imaging as noninvasive, nonradioactive method probing physiology well anatomy to monitor subtle changes subjects with IPF. Twenty subjects, nine healthy and eleven IPF, underwent HP Xe-129 ventilation MRI 3D-SBCSI. Spirometry was performed on all before imaging, DLCO hematocrit were measured IPF after imaging....
Background MRI with xenon‐129 gas (Xe MRI) can assess airflow obstruction and heterogeneity in lung diseases. Specifically, Xe may represent a sensitive modality for future therapeutic trials of cystic fibrosis (CF) therapies. The reproducibility has not yet been assessed the context multi‐site study. Purpose To determine same‐day repeatability 28‐day children CF. Study Type Four‐center prospective, longitudinal. Population Thirty‐eight (18 females, 47%), median interquartile range (IQR) age...
Xenon polarization Transfer Contrast (XTC) MRI pulse sequences permit the gas exchange of hyperpolarized xenon-129 in lung to be measured quantitatively. However, sequence parameter values employed previously published work were determined empirically without considering now-known rates and underlying physiology. By using a theoretical model for consumption magnetization during data acquisition, noise intensity computed gas-phase depolarization maps was minimized as function rate. With such...