Non-contrast Lung Perfusion Mapping Applied for New Insights in Cystic Fibrosis

Study Summary

Cystic fibrosis (CF) results in the thickening of mucus in the lungs and other organs due to dysfunction of a transmembrane conductance protein. This allows buildup of bacteria that results in inflammation, leading to tissue breakdown and loss of function. In the lungs, this process causes loss of air exchange structures progressing to diminished lung function. The exchange of oxygen in the lungs depends on both the integrity of air conduits and vasculature. Most clinical assessments, however, focus on ventilatory function, with the assumption that any vascular compromise is secondary. Nevertheless, there is evidence, some from the investigator's lab, to suggest that perfusion anomalies in the lung occur before signs of ventilatory dysfunction. Thus, the inflammatory processes of CF may impact pulmonary microvasculature specifically and concurrently or prior to damage to ventilatory structures. This study aims to apply a new MRI method to serially measure regional lung perfusion, without the use of contrast agent, in children with CF and to associate it with regional assessments of ventilation and to serum cytokines or proteomic markers of angiogenesis and inflammatory processes. The investigator's lab has recently developed a noninvasive, non-contrast, method of labeling blood flowing into the lungs and generating a map of perfusion. The investigator aims to couple this technique to existing methods using hyperpolarized Xenon to map ventilation. The investigator will apply these methods over time in CF patients, monitoring the relationship between regional perfusion and ventilation defects. This pilot work will provide the foundation for larger studies to establish the essential etiological role of perfusion deficits in CF.

Primary Outcome

Lung defect calculations (total and lobar defect percentages) will be performed by evaluating the percentage of voxels with signals below a threshold value of 60% of the total lung mean signal. This threshold (60%) represents our estimate of the visually accurate defect selection threshold for CF patients. To assign the pixels in the hyperpolarized Xenon gas (129Xe) MRI slices to a lobe, corresponding CT and/or UTE MRI images will be segmented and analyzed with custom MATLAB software. VDP for C

Conditions Studied

Interventions

• DRUG Initiation of CFTR Modulator
• DRUG Hyperpolarized Xenon 129

Study Locations (1)