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Abstract #2531

Inter-Observer Reproducibility of Longitudinal Hyperpolarized Helium-3 Magnetic Resonance Imaging of Chronic Obstructive Pulmonary Disease

Miranda Kirby1,2, Lindsay Mathew1,2, Andrew Wheatley1, David G. McCormack3, Grace Parraga1,4

1Imaging Research Laboratories, Robarts Research Institute, London, Ontario, Canada; 2Medical Biophysics, The University of Western Ontario; 3Division of Respirology, Department of Medicine, The University of Western Ontario; 4Graduate Program in Biomedical Engineering, The University of Western Ontario

Here we evaluate the associations between hyperpolarized Helium-3 Magnetic Resonance Imaging (3He MRI) longitudinal changes measured in Chronic Obstructive Pulmonary Disease (COPD) ex-smokers, with SNR and inter-observer variability. Spin density images for 15 subjects were segmented to obtain ventilation defect volume (VDV) measurements at baseline and 26 months. Inter-observer reproducibility was determined for two observers; ICC= .93, COV= 26% and r2= .78 (p<.0001). There was no significant relationship between image SNR and inter-observer variability (r=-.06, p=.75). Therefore, measurement variability is not affected by SNR and increases in VDV at follow-up may reflect COPD airway functional changes, suggestive of disease progression.