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Pulmonary ventilation visualized using hyperpolarized helium-3 and xenon-129 magnetic resonance imaging: differences in COPD and relationship to emphysema.
- Source :
- Journal of Applied Physiology; Mar2013, Vol. 114 Issue 6, p707-715, 9p
- Publication Year :
- 2013
-
Abstract
- In subjects with chronic obstructive pulmonary disease (COPD), hyperpolarized xenon-129 (<superscript>129</superscript>Xe) magnetic resonance imaging (MRI) reveals significantly greater ventilation defects than hyperpolarized helium-3 (³He) MRI. The physiological and/or morphological determinants of ventilation defects and the differences observed between hyperpolarized ³He and <superscript>129</superscript>Xe MRI are not yet understood. Here we aimed to determine the structural basis for the differences in ventilation observed between ³He and <superscript>129</superscript>Xe MRI in subjects with COPD using apparent diffusion coefficients (ADC) and computed tomography (CT). Ten COPD ex-smokers provided written, informed consent and underwent MRI, CT, spirometry, and plethysmography. ³He and <superscript>129</superscript>Xe MRI ventilation volume was generated using semiautomated segmentation, and ADC maps were registered to generate ADC values for lung regions of interest ventilated by both gases (ADC<subscript>HX</subscript>) and by ³He gas only (ADC<subscript>HO</subscript>). CT wall area percentage and the lowest 15th percentile point of the CT lung density histogram (HU<subscript>15%</subscript>) were also evaluated. For lung regions accessed by ³He gas only, mean ³He ADC<subscript>HO</subscript> was significantly greater than for regions accessed by both gases (ADC<subscript>HO</subscript> = 0.503 ± 0.119 cm²/s, ADC<subscript>HX</subscript> = 0.470 ± 0.125 cm²/s, P < 0.0001). The difference between ³He and <superscript>129</superscript>Xe ventilation volume was significantly correlated with CT HU<subscript>15%</subscript> (r = -65, P = 0.04) and ³He ADCHO (r = 0.70, P = 0.02), but not CT wall area percentage (r = -0.34, P = 0.33). In conclusion, in this small study in COPD subjects, we observed significantly decreased <superscript>129</superscript>Xe MRI ventilation compared with ³He MRI, and these regions of decreased <superscript>129</superscript>Xe ventilation were spatially and significantly correlated with regions of increased pulmonary emphysema, but not airway wall thickness. [ABSTRACT FROM AUTHOR]
- Subjects :
- OBSTRUCTIVE lung diseases
ARTIFICIAL respiration
MAGNETIC resonance imaging
Subjects
Details
- Language :
- English
- ISSN :
- 87507587
- Volume :
- 114
- Issue :
- 6
- Database :
- Complementary Index
- Journal :
- Journal of Applied Physiology
- Publication Type :
- Academic Journal
- Accession number :
- 127590206
- Full Text :
- https://doi.org/10.1152/japplphysiol.01206.2012