Open AccessOscillometry and pulmonary magnetic resonance imaging in asthma and COPD
Author(s) -
Eddy Rachel L.,
Westcott Andrew,
Maksym Geoffrey N.,
Parraga Grace,
Dandurand Ronald J.
Publication year - 2019
Publication title -
physiological reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.918
H-Index - 39
ISSN - 2051-817X
DOI - 10.14814/phy2.13955
Subject(s) - copd , medicine , asthma , cardiology , magnetic resonance imaging , respiratory system , airway obstruction , pulmonary disease , ventilation (architecture) , lung , airway , radiology , anesthesia , mechanical engineering , engineering
Developed over six decades ago, pulmonary oscillometry has re‐emerged as a noninvasive and effort‐independent method for evaluating respiratory‐system impedance in patients with obstructive lung disease. Here, we evaluated the relationships between hyperpolarized 3 He ventilation‐defect‐percent ( VDP ) and respiratory‐system resistance, reactance and reactance area ( A X ) measurements in 175 participants including 42 never‐smokers without respiratory disease, 56 ex‐smokers with chronic‐obstructive‐pulmonary‐disease ( COPD ), 28 ex‐smokers without COPD and 49 asthmatic never‐smokers. COPD participants were dichotomized based on x‐ray computed‐tomography ( CT ) evidence of emphysema (relative‐area CT ‐density‐histogram ≤ 950 HU ( RA 950 ) ≥ 6.8%). In asthma and COPD subgroups, MRI VDP was significantly related to the frequency‐dependence of resistance ( R 5‐19 ; asthma: ρ = 0.48, P = 0.0005; COPD : ρ = 0.45, P = 0.0004), reactance at 5 Hz ( X 5 : asthma, ρ = −0.41, P = 0.004; COPD : ρ = −0.38, P = 0.004) and A X (asthma: ρ = 0.47, P = 0.0007; COPD : ρ = 0.43, P = 0.0009). MRI VDP was also significantly related to R 5‐19 in COPD participants without emphysema ( ρ = 0.54, P = 0.008), and to X 5 in COPD participants with emphysema ( ρ = −0.36, P = 0.04). A X was weakly related to VDP in asthma ( ρ = 0.47, P = 0.0007) and COPD participants with ( ρ = 0.39, P = 0.02) and without ( ρ = 0.43, P = 0.04) emphysema. A X is sensitive to obstruction but not specific to the type of obstruction, whereas the different relationships for MRI VDP with R 5‐19 and X 5 may reflect the different airway and parenchymal disease‐specific biomechanical abnormalities that lead to ventilation defects.