RT Journal Article SR Electronic T1 New 133Xe Gas Trapping Index for Quantifying Severe Emphysema Before Partial Lung Volume Reduction JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 771 OP 775 DO 10.2967/jnumed.107.048637 VO 49 IS 5 A1 Jeffrey J. Mathews A1 Alan H. Maurer A1 Robert M. Steiner A1 Nathan Marchetti A1 Gerald Criner A1 John P. Gaughan A1 Harvey O. Coxson YR 2008 UL http://jnm.snmjournals.org/content/49/5/771.abstract AB Lung volume reduction (LVR) is an effective therapy for end-stage emphysema. Preliminary and postprocedure imaging is usually limited to CT for anatomic delineation of the location and severity of the most acutely affected lung zones. The purpose of this study was to investigate the potential of using a new quantitative gas trapping index (GTI) derived from a 133Xe ventilation scan to assess the severity of emphysema. Methods: Using the equilibration and washout phases of a 133Xe ventilation study, a GTI was compared with visual National Emphysema Treatment Trial (NETT) CT scoring, semiautomated CT densitometry, and 99mTc perfusion scintigraphy in 28 patients being evaluated for LVR. The GTI was calculated as the percentage of 133Xe gas retention in a 3-min washout image compared with the peak equilibrium image for 6 lung zones. Results: The GTI correlated best with the percentage of perfusion (−0.39, P < 0.0001) and the CT density scoring with the percentage of severe emphysema (0.36, P < 0.0001). There was less correlation with visual NETT CT scores (0.25, P < 0.001). Conclusion: This GTI, based on widely available 133Xe imaging, shows good correlation with other quantitative measures of emphysema that are anatomically based. Because this GTI provides a more functional assessment of gas trapping and airway disease, these results suggest that additional study is warranted to investigate its use as a functional measure of emphysema before and after LVR.