RESUMO
PURPOSE: To evaluate the dependency of the 129 Xe-red blood cell (RBC) chemical shift on blood oxygenation, and to use this relation for noninvasive measurement of pulmonary blood oxygenation in vivo with hyperpolarized 129 Xe NMR. METHODS: Hyperpolarized 129 Xe was equilibrated with blood samples of varying oxygenation in vitro, and NMR was performed at 1.5 T and 3 T. Dynamic in vivo NMR during breath hold apnea was performed at 3 T on two healthy volunteers following inhalation of hyperpolarized 129 Xe. RESULTS: The 129 Xe chemical shift in RBCs was found to increase nonlinearly with blood oxygenation at 1.5 T and 3 T. During breath hold apnea, the 129 Xe chemical shift in RBCs exhibited a periodic time modulation and showed a net decrease in chemical shift of â¼1 ppm over a 35 s breath hold, corresponding to a decrease of 7-10 % in RBC oxygenation. The 129 Xe-RBC signal amplitude showed a modulation with the same frequency as the 129 Xe-RBC chemical shift. CONCLUSION: The feasibility of using the 129 Xe-RBC chemical shift to measure pulmonary blood oxygenation in vivo has been demonstrated. Correlation between 129 Xe-RBC signal and 129 Xe-RBC chemical shift modulations in the lung warrants further investigation, with the aim to better quantify temporal blood oxygenation changes in the cardiopulmonary vascular circuit. Magn Reson Med 77:1399-1408, 2017. © 2016 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
Assuntos
Eritrócitos/metabolismo , Espectroscopia de Ressonância Magnética/métodos , Oxigênio/sangue , Artéria Pulmonar/metabolismo , Troca Gasosa Pulmonar/fisiologia , Isótopos de Xenônio/sangue , Administração por Inalação , Adulto , Estudos de Viabilidade , Humanos , Masculino , Compostos Radiofarmacêuticos/administração & dosagem , Compostos Radiofarmacêuticos/sangue , Compostos Radiofarmacêuticos/química , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Isótopos de Xenônio/administração & dosagem , Isótopos de Xenônio/químicaRESUMO
Magnetic resonance of hyperpolarized (129)Xe has found a wide field of applications in the analysis of biologically relevant fluids. Recently, it has been shown that the dissolution of hyperpolarized gas into the fluid via hollow-fiber membranes leads to bubble-free (129)Xe augmentation, and thus to an enhanced signal. In addition, hollow-fiber membranes permit a continuous operation mode. Herein, a quantitative magnetic resonance imaging and spectroscopy analysis of a customized hollow-fiber membrane module is presented. Different commercial hollow-fiber membrane types are compared with regard to their (129)Xe dissolution efficiency into porcine blood, its constituents, and other fluids. The presented study gives new insight into the suitability of these hollow-fiber membrane types for hyperpolarized gas dissolution setups.
Assuntos
Imageamento por Ressonância Magnética/métodos , Espectroscopia de Ressonância Magnética/métodos , Membranas Artificiais , Oxigênio/sangue , Polienos/química , Isótopos de Xenônio/sangue , Animais , Desenho de Equipamento , Hemoglobinas/análise , Imageamento por Ressonância Magnética/instrumentação , Espectroscopia de Ressonância Magnética/instrumentação , Porosidade , Solubilidade , Soluções , Propriedades de Superfície , SuínosRESUMO
We constructed a gas polarization system to test the feasibility of using hyperpolarized (129)Xe gas as an NMR (nuclear magnetic resonance) probe to explore brain function. Both in vitro and in vivo experiments were performed with a 4.7 T NMR spectrometer. Xenon spectra from human blood confirmed the existence of two peaks corresponding to red blood cells and plasma. In rat studies, three peaks at around 200 ppm were observed. Our results are consistent with previously reported data.
