Electronic Thesis and Dissertation Repository


Master of Science


Medical Biophysics


Parraga, Grace E.


Obstructive lung disease, including asthma and chronic obstructive pulmonary disease (COPD), is characterized by heterogeneous ventilation. Unfortunately, the underlying structure-function relationships and the relationships between measurements of heterogeneity and patient quality-of-life in obstructive lung disease are not well understood. Hyperpolarized noble gas MRI is used to visualize and quantify ventilation distribution and the forced oscillation technique (FOT) applies a multi-frequency pressure oscillation at the mouth to measure respiratory impedance to airflow (including resistance and reactance). My objective was to use FOT, ventilation MRI and computational airway tree modeling to better understand ventilation heterogeneity in asthma and COPD. FOT-measured respiratory system impedance was correlated with MRI ventilation heterogeneity and both were related to quality-of-life in asthma and COPD. FOT-measurements and model-predictions of reactance and small-airways resistance were correlated in asthma and COPD respectively. This study is the first to demonstrate the relationships between FOT-measured impedance, MRI ventilation heterogeneity, and patient quality-of-life.