Single‐breath xenon polarization transfer contrast (SB‐XTC): Implementation and initial results in healthy humans. Issue 2 (25th September 2012)

• Record Type: Journal Article
• Authors: Muradyan, Iga; Butler, James P.; Dabaghyan, Mikayel; Hrovat, Mirko; Dregely, Isabel; Ruset, Iulian; Topulos, George P.; Frederick, Eric; Hatabu, Hiroto; Hersman, William F.; Patz, Samuel
• Is Part Of: Journal of magnetic resonance imaging. Volume 37:Issue 2(2013)
• Page Start: 457
• Page End: 470
• Publication Date: 2012-09-25
• Subjects: Magnetic resonance imaging -- Periodicals; 616
• DOI: 10.1002/jmri.23823
• Languages: English
• ISSNs: 1053-1807

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <sec id="abs1-1" sec-type="section"> <title>Purpose:</title> <p>To implement and characterize a single‐breath xenon transfer contrast (SB‐XTC) method to assess the fractional diffusive gas transport <italic>F</italic> in the lung: to study the dependence of <italic>F</italic> and its uniformity as a function of lung volume; to estimate local alveolar surface area per unit gas volume <italic>S</italic><sub><italic>A</italic></sub>/<italic>V</italic><sub><italic>Gas</italic></sub> from multiple diffusion time measurements of <italic>F</italic>; to evaluate the reproducibility of the measurements and the necessity of <italic>B</italic><sub>1</sub> correction in cases of centric and sequential encoding.</p> </sec> <sec id="abs1-2" sec-type="section"> <title>Materials and Methods:</title> <p>In SB‐XTC three or four gradient echo images separated by inversion/saturation pulses were collected during a breath‐hold in eight healthy volunteers, allowing the mapping of <italic>F</italic> (thus <italic>S</italic><sub><italic>A</italic></sub>/<italic>V</italic><sub><italic>Gas</italic></sub>) and correction for other contributions such as <italic>T</italic><sub><italic>1</italic></sub> relaxation, RF depletion and <italic>B</italic><sub><italic>1</italic></sub> inhomogeneity from inherently registered data.</p> </sec> <sec id="abs1-3" sec-type="section"> <title>Results:</title> <p>Regional values of <italic>F</italic> and its distribution were obtained; both the mean value and heterogeneity of <italic>F</italic> increased with the decrease of lung volume. Higher values of <italic>F</italic> in the bases of the lungs in supine position were observed at lower volumes in all volunteers. Local <italic>S</italic><sub><italic>A</italic></sub>/<italic>V</italic><sub><italic>Gas</italic></sub> (with a mean ± standard deviation of <overline><italic>S</italic><sub><italic>A</italic></sub>/<italic>V</italic><sub><italic>Gas</italic></sub></overline> = 89±30 <italic>cm</italic><sup>−1</sup>) was estimated in vivo near functional residual capacity. Calibration of SB‐XTC on phantoms highlighted the necessity for <italic>B</italic><sub><italic>1</italic></sub> corrections when <italic>k</italic>‐space is traversed sequentially; with centric ordering <italic>B</italic><sub><italic>1</italic></sub> distribution correction is dispensable.</p> </sec> <sec id="abs1-4" sec-type="section"> <title>Conclusion:</title> <p>The SB‐XTC technique is implemented and validated for in vivo measurements of local <italic>S</italic><sub><italic>A</italic></sub>/<italic>V</italic><sub><italic>Gas</italic></sub>. J. Magn. Reson. Imaging 2013;37:457–470. © 2012 Wiley Periodicals, Inc.</p> </sec> </abstract>