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q‐space analysis of lung morphometry in vivo with hyperpolarized 3 He spectroscopy
Author(s) -
Shanbhag Dattesh D.,
Altes Talissa A.,
Miller G.Wilson,
Mata Jaime F.,
KnightScott Jack
Publication year - 2006
Publication title -
journal of magnetic resonance imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.563
H-Index - 160
eISSN - 1522-2586
pISSN - 1053-1807
DOI - 10.1002/jmri.20618
Subject(s) - spectroscopy , nuclear magnetic resonance , in vivo , nuclear magnetic resonance spectroscopy , space (punctuation) , in vivo magnetic resonance spectroscopy , physics , lung , nuclear medicine , chemistry , materials science , medicine , magnetic resonance imaging , radiology , computer science , biology , astronomy , microbiology and biotechnology , operating system
Purpose To examine the utility of a 3 He spectroscopic q‐space technique for detecting changes in lung morphometry in vivo. Materials and Methods A diffusion‐weighted spectroscopy sequence was used to collect global diffusion data from healthy adults ( N = 11), healthy children ( N = 5), and chronic obstructive pulmonary disease (COPD) patients ( N = 2) using 40 cc of hyperpolarized 3 He gas within a two second breathhold. Displacement probability profiles (DPP) were obtained by Fourier transformation of diffusion data with respect to q. A bi‐Gaussian model was used to decompose the DPPs into narrow and broad components, characterized by root‐mean‐square displacements X rms1 and X rms2 , respectively. Results In healthy adults, the narrow component (X rms,1 ) of the DPP had a mean displacement of 188 ± 10 μm, slightly less than the reported average size of the alveoli. The broad component (X rms,2 ) had a mean value of 474 ± 44 μm, comparable to the diameter of the respiratory bronchioles in the acinus. In children, both X rms1 (167 ± 4 μm) and X rms2 (382 ± 22 μm) compared to healthy adults ( P < 0.01). In COPD patients, the mean displacements were elevated (X rms1 : 265 ± 71 μm; X rms2 : 530 ± 109 μm) compared to healthy adults. Excellent correlation was found between rms displacements and age (age vs. X rms,1 : r = 0.78, P < 0.001; age vs. X rms,2 : r = 0.90, P < 0.001). Conclusion The q‐space parameters agreed remarkably well with published alveolar morphometry data. The results suggest that the technique may be sensitive to disease, as evident from the elevated mean displacements in COPD patients compared to healthy volunteers. Detailed lung microstructural information can be obtained using a very low volume of inhaled 3 He. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.