Assessing Bronchodilator Response In Patients With Asthma And Copd Using 19f-Mri

Background:¹⁹F-MRI of inhaled perfluoropropane (PFP) is emerging as a viable alternative to hyperpolarized-gas MRI for investigating lung ventilation properties. Aim: We assessed the ability of ¹⁹F-MRI to detect changes in regional ventilation in patients with asthma and patients with COPD following bronchodilator (BD) administration. Methods: 6 patients with asthma (2M, 4F; aged 18-69) and 6 patients with COPD (3M, 3F; aged 62-78) provided written informed consent and were screened for study eligibility. All patients underwent conventional spirometry and ¹⁹F-MRI scans pre- and post-administration of 2.5mg nebulised salbutamol, after withholding regular BD therapy for ~12hours. Each scan involved inhalation of a 79% PFP/21% oxygen gas mixture comprising 3 deep breaths of gas followed by a breath-hold, during which ¹⁹F-MR ventilation images were acquired. The percentage ventilated lung volume (%VV) was calculated for all ¹⁹F-MR images. Results: Paired t-tests showed post-BD %VV values were significantly increased in patients with asthma (mean_pre=88.9%, mean_post=93.4%; p=0.04) but not in patients with COPD (mean_pre=76.4%, mean_post=76.8%; p=0.32), corresponding to observed changes in spirometry and regional gas distribution (Figure 1). Conclusions:¹⁹F-MRI of inhaled PFP is capable of identifying post-BD response in patients with asthma. Future work will clarify this response in a larger cohort of patients across two UK study sites.