Bronchial thermoplasty guided by hyperpolarised gas magnetic resonance imaging in adults with severe asthma: a 1-year pilot randomised trial

Abstract

Patient-specific localisation of ventilation defects using hyperpolarised gas magnetic resonance imaging (MRI) introduces the possibility of regionally targeted bronchial thermoplasty (BT) for the treatment of severe asthma. We aimed to demonstrate that BT guided by MRI to ventilation defects reduces the number of radiofrequency activations while resulting in improved asthma quality-of-life and control scores that are non-inferior to standard BT.In a 1-year, pilot randomised-controlled trial, 14 patients with severe asthma who were clinically eligible to receive BT, underwent hyperpolarised gas MRI to characterise ventilation defects and were randomised to MRI-guided or standard BT. Endpoints were improved Asthma Quality-of-Life Questionnaire (AQLQ) and Asthma Control Questionnaire (ACQ) scores, the proportion of AQLQ and ACQ responders and the number of radiofrequency activations and bronchoscopy sessions.Participants who underwent MRI-guided BT received 53% fewer radiofrequency activations compared to those who had standard BT (p=0.003). At 12-months, the mean improvement from baseline was similar in both groups for AQLQ score (MRI-guided n=5, 1.8 [95% CI, 0.1 to 3.5], p=0.04; standard n=7, 0.7 [95% CI, −0.9 to 2.3], p=0.30) (p=0.25) and ACQ-5 score (MRI-guided n=5, −1.4 [95% CI, −2.6 to −0.2], p=0.03; standard n=7, −0.7 [95% CI, −1.3 to 0.0], p=0.04) (p=0.17). A similar proportion of participants in both groups achieved a clinically relevant improvement in AQLQ (MRI-guided, 80%; standard, 71%) and ACQ-5 scores (MRI-guided, 80%; standard, 57%).Hyperpolarised gas MRI-guided BT reduced the number of radiofrequency activations, and resulted in asthma quality-of-life and control improvements at 12-months that were non-inferior to standard BT.

Functional lung imaging using novel and emerging MRI techniques

“…The high sensitivity ( 55 , 275–277 ) and repeatability of HP-MRI biomarkers may enable future clinical trials to be undertaken with smaller sample sizes ( 125 , 171 ). Emerging evidence also support its role in guiding bronchial thermoplasty ( 278 , 279 ) and placement of endobronchial valves ( 280 , 281 ). While diffusion-weighted and gas-exchange imaging are at an earlier stage of development, we believe they will develop into its full potential over time.…”

Quantification of pulmonary functional MRI: state-of-the-art and emerging image processing methods and measurements

“…Hence, functional-avoidance in management and treatment planning for such patients is an important avenue that can be strengthened using PfMRI measurements. Hyperpolarized gas MRI is beautifully positioned to identify low-functioning regions, and clinical trials are currently underway to evaluate the 129 Xe MRI measurements of lung function (taken together with perfusion, alveolar microstructure and collateral ventilation) in advance of resection, bronchial thermoplasty and lung transplantation in cancer (Rankine et al 2018, Hall et al 2020, Svenningsen et al 2021b.…”

Imaging in Asthma Management

“…6 ). 100 101 102 Specifically, the segments within the lungs with the greatest degree of ventilation defects measured by hyperpolarized gas MRI can be targeted in BT. In doing so, the regions of the lungs most contributing to asthma symptoms are directly treated, which in preliminary studies appears to improve the safety and efficiency of this technique.…”