title: Hyperpolarized (129)Xe MRI: a viable functional lung imaging modality?
abstract: The majority of researchers investigating hyperpolarized gas MRI as a candidate functional lung imaging modality have used (3)He as their imaging agent of choice rather than (129)Xe. This preference has been predominantly due to, (3)He providing stronger signals due to higher levels of polarization and higher gyromagnetic ratio, as well as its being easily available to more researchers due to availability of polarizers (USA) or ease of gas transport (Europe). Most researchers agree, however, that hyperpolarized (129)Xe will ultimately emerge as the imaging agent of choice due to its unlimited supply in nature and its falling cost. Our recent polarizer technology delivers vast improvements in hyperpolarized (129)Xe output. Using this polarizer, we have demonstrated the unique property of xenon to measure alveolar surface area noninvasively. In this article, we describe our human protocols and their safety, and our results for the measurement of the partial pressure of pulmonary oxygen (pO(2)) by observation of (129)Xe signal decay. We note that the measurement of pO(2) by observation of (129)Xe signal decay is more complex than that for (3)He because of an additional signal loss mechanism due to interphase diffusion of (129)Xe from alveolar gas spaces to septal tissue. This results in measurements of an equivalent pO(2) that accounts for both traditional T(1) decay from pO(2) and that from interphase diffusion. We also provide an update on new technological advancements that form the foundation for an improved compact design polarizer as well as improvements that provide another order-of-magnitude scale-up in xenon polarizer output.
authors: Center for Pulmonary Functional Imaging, Brigham and Women's Hospital, 221 Longwood Avenue, Boston, MA 02115, USA. patz@bwh.harvard.edu
authors: Samuel
authors: S
authors: Patz
authors: F William
authors: FW
authors: Hersman
authors: Iga
authors: I
authors: Muradian
authors: Mirko I
authors: MI
authors: Hrovat
authors: Iulian C
authors: IC
authors: Ruset
authors: Stephen
authors: S
authors: Ketel
authors: Francine
authors: F
authors: Jacobson
authors: George P
authors: GP
authors: Topulos
authors: Hiroto
authors: H
authors: Hatabu
authors: James P
authors: JP
authors: Butler
mesh_terms: D000280:Administration, Inhalation; D000818:Animals; D003287:Contrast Media; D004867:Equipment Design; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007834:Lasers; D008168:Lung / Q000502:physiology*; D008279:Magnetic Resonance Imaging / Q000295:instrumentation / Q000379:methods*; D010100:Oxygen / Q000097:blood; D010101:Oxygen Consumption / Q000502:physiology; D010313:Partial Pressure; D011650:Pulmonary Alveoli / Q000033:anatomy & histology; D011653:Pulmonary Diffusing Capacity / Q000502:physiology; D012413:Rubidium / Q000737:chemistry; D012449:Safety; D013679:Technology, Radiologic / Q000295:instrumentation; D014692:Ventilation-Perfusion Ratio / Q000502:physiology; D014979:Xenon Isotopes / Q000737:chemistry
chemical_list: D003287:Contrast Media; D014979:Xenon Isotopes; D012413:Rubidium; D010100:Oxygen