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Quantitative analysis of hyperpolarized 3 He ventilation changes in mice challenged with methacholine
Author(s) -
Mistry Nilesh N.,
Thomas Abraham,
Kaushik S. Sivaram,
Johnson G. Allan,
Driehuys Bastiaan
Publication year - 2010
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.22311
Subject(s) - methacholine , ventilation (architecture) , chemistry , nuclear magnetic resonance , cardiology , medicine , physics , lung , respiratory disease , thermodynamics
The capability to use high‐resolution 3 He MRI to depict regional ventilation changes and airway narrowing in mice challenged with methacholine (MCh) offers the opportunity to gain new insights into the study of asthma. However, to fully exploit the value of this novel technique, it is important to move beyond visual inspection of the images toward automated and quantitative analysis. To address this gap, we describe a postprocessing approach to create ventilation difference maps to better visualize and quantify regional ventilation changes before and after MCh challenge. We show that difference maps reveal subtle changes in airway caliber, and highlight both focal and diffuse regional alterations in ventilation. Ventilation changes include both hypoventilation and compensatory areas of hyperventilation. The difference maps can be quantified by a histogram plot of the ventilation changes, in which the standard deviation increases with MCh dose ( R 2 = 0.89). This method of analysis is shown to be more sensitive than simple threshold‐based detection of gross ventilation defects. Magn Reson Med 63:658–666, 2010. © 2010 Wiley‐Liss, Inc.