Estudio de localización

In summary, we evaluated hyperpolarized 3He MRI ventilation defects—a surrogate measurement of airway function—in the first, large imaging study of healthy older never- smokers with no history of chronic heart or lung disease. While a minority of subjects reported occupational exposures, most subjects had visually obvious ventilation defects that did not change after DI or salbutamol administration suggesting that terminal airway closure or narrowing may be a normal age-related lung finding. While there were no differences in CPET or conventional pulmonary function measurements between subjects with and without ventilation defects, FEV1%pred in combination with IC%pred and Raw%pred

predicted VDP in a multivariate regression model. Taken together, these findings provide a better understanding of the nature of ventilation defects in healthy older never-smokers.

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2.5

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CHAPTER 3

3

ULTRA-SHORT

ECHO

TIME

PULMONARY

MAGNETIC RESONANCE IMAGING: EVALUATION

AND REPRODUCIBILITY IN COPD SUBJECTS WITH

AND WITHOUT BRONCHIECTASIS

To better understand the potential for ultra-short echo time MRI to provide quantitative COPD endpoints, we evaluated the reproducibility and consequences of signal-intensity in COPD subjects with and without bronchiectasis. We compared UTE MR measurements with CT measurements of radiodensity and pulmonary function test measurements.

The contents of this chapter were previously published in the Journal of Magnetic Resonance Imaging: W Ma, K Sheikh, S Svenningsen, D Pike, F Guo, R Etemad-Rezai, J Leipsic, HO Coxson, DG McCormack, and G Parraga. J Magn Reson Imaging 2015; 41(5):1465-1474. Permission to reproduce this article was granted by John Wiley & Sons and is provided in Appendix A.