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 emerging in the alveolar airspaces.
Materials And Methods: Five Fischer 344 rats that weighed 200-425 g were prepared for imaging according to an institutional animal care and use committee-approved protocol. Rats were ventilated, and a 3-F catheter was placed in the jugular (n = 1) or a 24-gauge catheter in the tail (n = 4) vein. Imaging and spectroscopy of gas-phase (129)Xe were performed after injecting 5 mL of half-normal saline saturated with (129)Xe hyperpolarized to 12%. Corresponding ventilation images were obtained during conventional inhalation delivery of hyperpolarized (129)Xe.
Results: Injections of (129)Xe-saturated saline were well tolerated and produced a strong gas-phase (129)Xe signal in the airspaces that resulted from (129)Xe transport through the pulmonary circulation and diffusion across the blood-gas barrier. After a single injection, the emerging (129)Xe gas could be detected separately from (129)Xe remaining in the blood and was imaged with an in-plane resolution of 1 x 1 mm and a signal-to-noise ratio of 25. Images in one rat revealed a matched ventilation-perfusion deficit, while images in another rat showed that xenon gas exchange was temporarily impaired after saline overload, with recovery of function 1 hour later.
Conclusion: MR imaging of gas-phase (129)Xe emerging in the pulmonary airspaces after intravenous injection has the potential to become a sensitive and minimally invasive new tool for regional evaluation of pulmonary perfusion and gas exchange.
Supplemental Material: http://radiology.rsnajnls.org/cgi/content/full/2513081550/DC1.
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http://dx.doi.org/10.1148/radiol.2513081550 | DOI Listing |
Magn Reson Med
March 2025
Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
Purpose: To compare pulmonary function metrics obtained with hyperpolarized xenon-129 (HXe) MRS, using chemical shift saturation recovery (CSSR) and CSI-CSSR, in healthy rats and a rat model of radiation-induced lung injury.
Methods: HXe-MR data were acquired in two healthy rats and one rat with radiation-induced lung injury using whole-lung spectroscopy and CSI-CSSR techniques. The CSI-CSSR acquisitions were performed with both fixed TE and variable TE.
J Phys Chem Lett
May 2024
NMR Research Unit, Faculty of Science, University of Oulu, P.O.Box 3000, FI-90014 Oulu, Finland.
We exploited Xe NMR to investigate xenon gas uptake and dynamics in a porous liquid formed by dissolving porous organic cages in a cavity-excluded solvent. Quantitative Xe NMR shows that when the amount of xenon added to the sample is lower than the amount of cages present (subsaturation), the porous liquid absorbs almost all xenon atoms from the gas phase, with 30% of the cages occupied with a Xe atom. A simple two-site exchange model enables an estimate of the chemical shift of Xe in the cages, which is in good agreement with the value provided by first-principles modeling.
View Article and Find Full Text PDFEur Radiol
October 2024
Institute for Diagnostic and Interventional Radiology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany.
Objectives: To investigate potential presence and resolution of longer-term pulmonary diffusion limitation and microvascular perfusion impairment in COVID-19 convalescents.
Materials And Methods: This prospective, longitudinal study was carried out between May 2020 and April 2023. COVID-19 convalescents repeatedly and age/sex-matched healthy controls once underwent MRI including hyperpolarized Xe MRI.
Radiol Cardiothorac Imaging
June 2023
From the Departments of Biomedical Engineering (W.J.G., J.P.M., G.W.M.), Radiology and Medical Imaging (K.Q., N.J.T., J.F.M., A.M.R., J.P.M., G.W.M.), Medicine (M.H., Y.M.S.), Public Health Sciences (J.T.P.), and Physics (G.W.M.), University of Virginia, 480 Ray C. Hunt Dr, Box 801339, Charlottesville, VA 22908; Department of Radiation Oncology, City of Hope National Medical Center, Duarte, Calif (K.Q.); Department of Biomedical Engineering, Zhejiang University, Hangzhou, China (L.Z.); and Department of Radiology, University of Missouri, Columbia, Mo (T.A.A.).
Purpose: To assess the effect of lung volume on measured values and repeatability of xenon 129 (Xe) gas uptake metrics in healthy volunteers and participants with chronic obstructive pulmonary disease (COPD).
Materials And Methods: This Health Insurance Portability and Accountability Act-compliant prospective study included data (March 2014-December 2015) from 49 participants (19 with COPD [mean age, 67 years ± 9 (SD)]; nine women]; 25 older healthy volunteers [mean age, 59 years ± 10; 20 women]; and five young healthy women [mean age, 23 years ± 3]). Thirty-two participants underwent repeated Xe and same-breath-hold proton MRI at residual volume plus one-third forced vital capacity (RV+FVC/3), with 29 also undergoing one examination at total lung capacity (TLC).
Molecules
November 2022
Department of Translational Imaging, Genentech Inc., South San Francisco, CA 94080, USA.
Although critical for development of novel therapies, understanding altered lung function in disease models is challenging because the transport and diffusion of gases over short distances, on which proper function relies, is not readily visualized. In this review we summarize progress introducing hyperpolarized Xe imaging as a method to follow these processes in vivo. The work is organized in sections highlighting methods to observe the gas replacement effects of breathing (Gas Dynamics during the Breathing Cycle) and gas diffusion throughout the parenchymal airspaces (3).
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