The difference in ventilation heterogeneity between asthmatic and healthy subjects quantified using hyperpolarized 3He MRI
UMass Chan Affiliations
Department of RadiologyDocument Type
Journal ArticlePublication Date
2008-11-22Keywords
AdultAnti-Asthmatic Agents
Asthma
Bronchoconstrictor Agents
Female
Helium
Humans
Magnetic Resonance Imaging
Male
Methacholine Chloride
Middle Aged
Pilot Projects
Pulmonary Ventilation
Respiratory Function Tests
Young Adult
Life Sciences
Medicine and Health Sciences
Metadata
Show full item recordAbstract
In this pilot study, algorithms for quantitatively evaluating the distribution and heterogeneity of human ventilation imaged with hyperpolarized (HP) (3)He MRI were developed for the goal of examining structure-function relationships within the asthmatic lung. Ten asthmatic and six healthy human subjects were imaged with HP (3)He MRI before bronchial challenge (pre-MCh), after bronchial challenge (post-MCh), and after a series of deep inspirations (post-DI) following challenge. The acquired images were rigidly coregistered. Local voxel fractional ventilation was computed by setting the sum of the pixel intensity within the lung region in each image to 1 liter of inhaled (3)He mixture. Local ventilation heterogeneity was quantified by computing regional signal coefficient of variation. Voxel fractional ventilation histograms and overall heterogeneity scores were then calculated. Asthmatic subjects had a higher ventilation heterogeneity to begin with (P = 0.025). A methacholine challenge elevated ventilation heterogeneity for all subjects (difference: P = 0.08). After a DI postchallenge, this heterogeneity reversed substantially toward the baseline state for healthy subjects but only minimally in asthmatic subjects. This difference was significant in absolute quantity (difference: P = 0.007) as well as relative to the initial increase (difference: P = 0.03). These findings suggest that constriction heterogeneity is not a characteristic unique to asthmatic airway trees but rather a behavior intrinsic to all airway trees when provoked. Once ventilation heterogeneity is established, it is the lack of reversal following DIs that distinguishes asthmatics from non-asthmatics.Source
J Appl Physiol. 2009 Mar;106(3):813-22. Epub 2008 Nov 20. Link to article on publisher's siteDOI
10.1152/japplphysiol.01133.2007Permanent Link to this Item
http://hdl.handle.net/20.500.14038/39345PubMed ID
19023025Related Resources
Link to Article in PubMedae974a485f413a2113503eed53cd6c53
10.1152/japplphysiol.01133.2007