MR Imaging of Mouse Lung Using Hyperpolarized 3He: Image Acquisition and T1 Estimation under Spontaneous Respiration

• IMAI Hirohiko

  Department of Medical Physics and Engineering, Division of Health Sciences, Graduate School of Medicine, Osaka University

• NARAZAKI Michiko

  Department of Medical Physics and Engineering, Division of Health Sciences, Graduate School of Medicine, Osaka University

• INOSHITA Hiroyuki

  Department of Medical Physics and Engineering, Division of Health Sciences, Graduate School of Medicine, Osaka University

• KIMURA Atsuomi

  Department of Medical Physics and Engineering, Division of Health Sciences, Graduate School of Medicine, Osaka University

• FUJIWARA Hideaki

  Department of Medical Physics and Engineering, Division of Health Sciences, Graduate School of Medicine, Osaka University

抄録

Purpose: The purpose of this study was to acquire a hyperpolarized (HP) ³He image of the mouse lung and to estimate ³He T₁ in the lung from wash-out curve analysis under spontaneous respiration.<br> Materials and Methods: We first tested the K-Rb hybrid method for the spin-exchange optical pumping (SEOP) of ³He using a home-built noble gas polarizer operated at atmospheric pressure and then applied it to MR imaging and spectroscopy of the mouse lung. The longitudinal relaxation time (T₁) of ³He in the mouse lung was estimated under spontaneous respiration by exploiting a novel method in which SF₆ gas at thermal equilibrium was utilized in combination with the HP ³He gas in the quantitative wash-out curve analysis. This method utilizes the difference in the profile of the wash-out curve of HP ³He and SF₆ at thermal equilibrium. That is, the slope of the ³He wash-out curve in the semi-logarithmic plots is affected by 3 factors, including RF pulse angle, respiration, and T₁, whereas the slope of the SF₆ wash-out curve is only the function of respiratory term.<br> Results: A ³He lung image was obtained successfully, and we were able to estimate successfully ³He T₁ in the mouse lung under spontaneous respiration using a novel method; the estimated T₁ value was 68±25 s, which was reasonable compared with the value calculated from the literature data measured during breath-hold.<br> Conclusion: We succeeded in acquiring the first ³He image of mouse lung in vivo in this country, and our proposed method of estimating ³He T₁ in the lung under spontaneous respiration is noninvasive and readily applied to animals and would be useful to evaluate the alveolar gas exchange function as well as oxygen partial pressure (p_O2) in lungs of animals.<br>

収録刊行物

• Magnetic Resonance in Medical Sciences

  Magnetic Resonance in Medical Sciences 5 (2), 57-64, 2006

  日本磁気共鳴医学会

キーワード

• hyperpolarized ³He
• lung image
• wash-out
• longitudinal relaxation time
• SF₆

詳細情報

• CRID: 1390282680171630208
• NII論文ID: 10018258466
• NII書誌ID: AA11648770
• DOI: 10.2463/mrms.5.57
• ISSN: 18802206
• ISSN: 13473182
• Web Site: https://www.jstage.jst.go.jp/article/mrms/5/2/5_2_57/_pdf
• Web Site: https://search.jamas.or.jp/link/ui/2007017456
• 本文言語コード: en
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