A method for MRI-guided bronchoscopy to identify obstructed airway segments.

Abstract

Bronchoscopy is not conventionally guided by prior knowledge of segmental airway obstruction. Hyperpolarized gas magnetic resonance imaging (MRI) ventilation abnormalities and computed tomography (CT) air trapping are related to lung function and asthma severity but have not been used to target segmental inflammation and remodeling. We evaluate the feasibility of using bronchoscopy guided by ³He MRI and CT to reveal differences in inflammatory response, morphology, and cellular activity in poorly- (defect) versus well-ventilated (control) lung regions. Eleven participants (5 female; age, 22.8 ± 3.4 years; 9 asthma) who experienced a cold with increased lower airway symptoms underwent ³He MRI and/or CT at least 6 weeks after recovery. Differences between defect and control regions were compared. In defect as compared to control sites, bronchoalveolar lavage neutrophils (p = 0.06) and granulocytes (p = 0.08) trended towards an increase; inflammatory mediators (i.e., 15-epi-LXA4, LXA4) were also significantly different (p < 0.05) between sites. Correlations were observed between macrophages, neutrophils, and eosinophils with inflammatory mediators (i.e., 15-epi-LXA4, LXA4, LTB4). Correlations were observed for macrophages and neutrophils with 15-epi-LXA4, and eosinophils with LXA4 and leukotriene B4. Basement membrane wall thickness was similar for defect versus control sites (p = 0.9). These results support the feasibility of image-guided methods to identify airway obstruction phenotypes.