Hyperpolarized Helium 3 MRI in Mild-to-Moderate Asthma: Prediction of Postbronchodilator Reversibility.

Abstract

Background Longitudinal progression to irreversible airflow limitation occurs in approximately 10% of patients with asthma, but it is difficult to identify patients who are at risk for this transition. Purpose To investigate 6-year longitudinal changes in hyperpolarized helium 3 (3He) MRI ventilation defects in study participants with mild-to-moderate asthma and identify predictors of longitudinal changes in postbronchodilator forced expiratory volume in 1 second (FEV1) reversibility Materials and Methods Spirometry and hyperpolarized 3He MRI were evaluated in participants with mild-to-moderate asthma in two prospectively planned visits approximately 6 years apart. Participants underwent methacholine challenge at baseline (January 2010 to April 2011) and pre- and postbronchodilator evaluations at follow-up (November 2016 to June 2017). FEV1 and MRI ventilation defects, quantified as ventilation defect volume (VDV), were compared between visits by using paired t tests. Participants were dichotomized by postbronchodilator change in FEV1 at follow-up, and differences between reversible and not-reversible groups were determined by using unpaired t tests. Multivariable models were generated to explain postbronchodilator FEV1 reversibility at follow-up. Results Eleven participants with asthma (mean age, 42 years ± 9 [standard deviation]; seven men) were evaluated at baseline and after mean 78 months ± 7. Medications, exacerbations, FEV1 (76% predicted vs 76% predicted; P = .91), and VDV (240 mL vs 250 mL; P = .92) were not different between visits. In eight of 11 participants (73%), MRI ventilation defects at baseline were at the same location in the lung at follow-up MRI. In the remaining three participants (27%), MRI ventilation defects worsened at the same lung locations as depicted at baseline methacholine-induced ventilation. At follow-up, postbronchodilator FEV1 was not reversible in six of 11 participants; the concentration of methacholine to decrease FEV1 by 20% (PC20) was greater in FEV1-irreversible participants at follow-up (P = .01). In a multivariable model, baseline MRI VDV helped to predict postbronchodilator reversibility at follow-up (R 2 = 0.80; P < .01), but PC20, age, and FEV1 did not (R 2 = 0.63; P = .15). Conclusion MRI-derived, spatially persistent ventilation defects predict postbronchodilator reversibility 78 months ± 7 later for participants with mild-to-moderate asthma in whom there were no changes in lung function, medication, or exacerbations. © RSNA, 2019 Online supplemental material is available for this article. See also the editorial by Stojanovska in this issue.

• Authors: Rachel L Eddy, Sarah Svenningsen, Christopher Licskai, David G McCormack, Grace Parraga
• Journal: Radiology (Radiology) Vol. 293 Issue 1 Pg. 212-220 (10 2019) ISSN: 1527-1315 [Electronic] United States
• PMID: 31385758 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Bronchodilator Agents
• Isotopes
• Helium
• Helium-3

Topics

• Adult
• Asthma (diagnostic imaging, drug therapy, physiopathology)
• Bronchial Provocation Tests (statistics & numerical data)
• Bronchodilator Agents (therapeutic use)
• Female
• Follow-Up Studies
• Helium
• Humans
• Isotopes
• Longitudinal Studies
• Lung (diagnostic imaging, drug effects, physiopathology)
• Magnetic Resonance Imaging (methods)
• Male
• Middle Aged
• Predictive Value of Tests