Dante Capaldi BSC, Presenter: Nothing to Disclose

Khadija Sheikh, Abstract Co-Author: Nothing to Disclose

Fumin Guo, Abstract Co-Author: Nothing to Disclose

Sarah Svenningsen BSC, Abstract Co-Author: Nothing to Disclose

David McCormack MD, Abstract Co-Author: Nothing to Disclose

Grace Parraga PhD, Abstract Co-Author: Nothing to Disclose

Fourier-decomposition of pulmonary magnetic resonance imaging (FDMRI) exploits free-breathing 1H MRI and non-rigid registration to generate ventilation images. FDMRI was recently compared with SPECT-CT and 3He MRI in a porcine model, but there have been no demonstrations in subjects with COPD. Our objective was to evaluate ex-smokers using FDMRI, 3He MRI, CT, and pulmonary function tests. We hypothesized that ventilation defects measured using FDMRI would be spatially and quantitatively correlated with 3He MRI ventilation defects and emphysematous bullae. 

13 ex-smokers (66±9yr) provided written informed consent to imaging, spirometry, and plethysmography. 3He and dynamic free tidal-breathing 1H MRI were acquired over a period of two minutes on a 3T system (GEHC). For FDMRI, non-rigid registration was performed using modality independent neighbourhood descriptor (MIND) deformable registration that employs a local image descriptor as the similarity measurement. Hyperpolarized 3He (VDPHe) and FDMRI (VDPFD) ventilation defect percents and CT attenuation values < -950 Hounsfield units (RA950) were compared using linear regression and Dice Similarity coefficients (DSC). 

In all ex-smokers (GOLD stage I, n=2; stage II, n=5; stage III/IV, n=4; no COPD, n=2), there were visually obvious ventilation defects. MRI and CT for a representative ex-smoker (75yr female pack-year=41, FEV1=46%pred, RA950=26%, VDPHe=36%) in Figure 1 shows the qualitative agreement in the right upper lobe for ventilation defects and a large emphysematous bulla. For all subjects, there was a significant and positive correlation for VDPFD with VDPHe (r2=.64, p=.001) and RA950 (r2=.62, p=.001) and the DSC was .71±.10.

In ex-smokers, FDMRI ventilation defects were spatially and quantitatively correlated with 3He MRI ventilation defects. Emphysema, quantified by RA950, was spatially and significantly correlated with VDP. For subjects with emphysematous bullae, the long time-constants for lung filling/emptying may be related to ventilation defects detected using free-breathing FDMRI and breath-hold 3He MRI.

In 13 ex-smokers, some with emphysematous bullae, FDMRI ventilation defects were spatially and quantitatively related to emphysema and hyperpolarized 3He MRI ventilation defects.

Capaldi, D, Sheikh, K, Guo, F, Svenningsen, S, McCormack, D, Parraga, G, Fourier-decomposition Pulmonary Magnetic Resonance Imaging Ventilation Defects in Ex-smokers: Relationship to Emphysema and 3He Ventilation Defects.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14018829.html