MR Imaging of Mouse Lung Using Hyperpolarized ^<3>He : Image Acquisition and T_1 Estimation under Spontaneous Respiration

Access this Article

Search this Article

Author(s)

    • 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

Abstract

Purpose: The purpose of this study was to acquire a hyperpolarized (HP) <sup>3</sup>He image of the mouse lung and to estimate <sup>3</sup>He T<sub>1</sub> 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 <sup>3</sup>He 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 (T<sub>1</sub>) of <sup>3</sup>He in the mouse lung was estimated under spontaneous respiration by exploiting a novel method in which SF<sub>6</sub> gas at thermal equilibrium was utilized in combination with the HP <sup>3</sup>He gas in the quantitative wash-out curve analysis. This method utilizes the difference in the profile of the wash-out curve of HP <sup>3</sup>He and SF<sub>6</sub> at thermal equilibrium. That is, the slope of the <sup>3</sup>He wash-out curve in the semi-logarithmic plots is affected by 3 factors, including RF pulse angle, respiration, and T<sub>1</sub>, whereas the slope of the SF<sub>6</sub> wash-out curve is only the function of respiratory term.<br> Results: A <sup>3</sup>He lung image was obtained successfully, and we were able to estimate successfully <sup>3</sup>He T<sub>1</sub> in the mouse lung under spontaneous respiration using a novel method; the estimated T<sub>1</sub> 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 <sup>3</sup>He image of mouse lung <i>in vivo</i> in this country, and our proposed method of estimating <sup>3</sup>He T<sub>1</sub> 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<sub>O2</sub>) in lungs of animals.<br>

Journal

  • MRMS  

    MRMS 5(2), 57-64, 2006-07-10 

    Japanese Society for Magnetic Resonance in Medicine

References:  28

You must have a user ID to see the references.If you already have a user ID, please click "Login" to access the info.New users can click "Sign Up" to register for an user ID.

Cited by:  1

You must have a user ID to see the cited references.If you already have a user ID, please click "Login" to access the info.New users can click "Sign Up" to register for an user ID.

Codes

  • NII Article ID (NAID)
    10018258466
  • NII NACSIS-CAT ID (NCID)
    AA11648770
  • Text Lang
    ENG
  • Article Type
    Journal Article
  • ISSN
    13473182
  • Data Source
    CJP  CJPref  J-STAGE 
Page Top