Single-Session Bronchial Thermoplasty Guided by 129 Xe Magnetic Resonance Imaging. A Pilot Randomized Controlled Clinical Trial.

Rationale: Adverse events have limited the use of bronchial thermoplasty (BT) in severe asthma. Objectives: We sought to evaluate the effectiveness and safety of using ¹²⁹ Xe magnetic resonance imaging ( ¹²⁹ Xe MRI) to prioritize the most involved airways for guided BT. Methods: Thirty subjects with severe asthma were imaged with volumetric computed tomography and ¹²⁹ Xe MRI to quantitate segmental ventilation defects. Subjects were randomized to treatment of the six most involved airways in the first session (guided group) or a standard three-session BT (unguided). The primary outcome was the change in Asthma Quality of Life Questionnaire score from baseline to 12 weeks after the first BT for the guided group compared with after three treatments for the unguided group. Measurements and Main Results: There was no significant difference in quality of life after one guided compared with three unguided BTs (change in Asthma Quality of Life Questionnaire guided = 0.91 [95% confidence interval, 0.28-1.53]; unguided = 1.49 [95% confidence interval, 0.84-2.14]; P  = 0.201). After one BT, the guided group had a greater reduction in the percentage of poorly and nonventilated lung from baseline when compared with unguided (-17.2%; P  = 0.009). Thirty-three percent experienced asthma exacerbations after one guided BT compared with 73% after three unguided BTs ( P  = 0.028). Conclusions: Results of this pilot study suggest that similar short-term improvements can be achieved with one BT treatment guided by ¹²⁹ Xe MRI when compared with standard three-treatment-session BT with fewer periprocedure adverse events.