What is the minimal clinically important difference for helium-3 magnetic resonance imaging ventilation defects?
Letter to the Editor
The European Respiratory Journal
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Pulmonary magnetic resonance imaging (MRI) using inhaled polarised gases provides a way to directly visualise and sensitively measure lung ventilation abnormalities or ventilation defects ; the burden in individual patients may be directly quantified as the percent ventilation volume , ventilation defect volume (VDV)  or ventilation defect percent (VDP) , which is VDV normalised to the total lung volume. In patients with asthma, MRI ventilation defects worsen during methacholine  and exercise challenge [5, 6], and respond to bronchodilation [5, 6]. However, it is still unknown if quantitative changes in MRI ventilation abnormalities directly reflect changes in patient-related outcomes like symptoms; this is important when considering MRI for clinical and research studies in asthma patients, which require an understanding of the minimal clinically important difference (MCID).
Citation of this paper:
Eddy RL, Svenningsen S, McCormack DG, et al. What is the minimal clinically important difference for helium-3 magnetic resonance imaging ventilation defects? Eur Respir J 2018; 51: 1800324 [https://doi.org/10.1183/13993003.00324-2018].