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|Title:||Characterisation of Acinar Airspace Involvement in Asthma using Inert Gas Washout and Hyperpolarised 3Helium Magnetic Resonance|
Brightling, Christopher E.
|Publisher:||Elsevier for American Academy of Allergy, Asthma and Immunology, Mosby|
|Citation:||Journal of Allergy and Clinical Immunology|
|Abstract:||Background The multiple breath washout (MBW) parameter Sacin is thought to be a marker of acinar airway involvement, but has not been validated using quantitative imaging techniques in asthma. Objective We aimed to utilise 3He diffusion magnetic resonance ( 3 He-MR) at multiple diffusion timescales and quantitative computed tomography (CT) densitometry to determine the nature of acinar airway involvement in asthma. Methods Thirty-seven patients with asthma and seventeen age-matched healthy controls underwent spirometry, body plethysmography, MBW (using the tracer gas sulphur hexafluoride) and He-MR. A subset of patients with asthma (n = 27) underwent quantitative CT densitometry. Results Ninety-four percent (16/17) of patients with an elevated Sacin had GINA treatment steps 4/5 asthma and 13/17 had refractory disease. The apparent diffusion coefficient (ADC) of 3 He at 1s was significantly higher in patients with Sacin-high asthma compared to healthy controls (0.024 vs 0.017, p < 0.05). Sacin correlated strongly with ADC at 1s (R = 0.65, p < 0.001), but weakly with ADC at 13ms (R = 0.38, p < 0.05). ADC at both 13ms and 1s correlated strongly with the mean lung density expiratory / inspiratory ratio, a CT marker of expiratory air trapping (R = 0.77, p < 0.0001 for ADC at 13ms; R = 0.72, p < 0.001 for ADC at 1s). Conclusion Sacin is associated with alterations in long-range diffusion within the acinar airways and gas trapping. The precise anatomical nature and mechanistic role in severe asthma requires further evaluation.|
|Embargo on file until:||1-Jan-10000|
|Rights:||Archived with reference to SHERPA/RoMEO and publisher website. © 2015. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/ 12 Month embargo|
|Appears in Collections:||Published Articles, Dept. of Infection, Immunity and Inflammation|
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