Inspiratory/expiratory xenon-enhanced area-detector CT: Capability for quantitative assessment of lung ventilation changes in surgically treated non-small cell lung cancer patients

Purpose: To evaluate the capability of inspiratory/expiratory Xe-enhanced ADCT for assessment of changes in pulmonary function and regional ventilation of surgically treated NSCLC patients. Method and materials: Forty consecutive surgically treated NSCLC patients underwent pre- and postoperative inspiratory/expiratory Xe-enhanced ADCT and pulmonary function tests. For each patient, pre- and post-operative data were analyzed and pre- and post-operative wash-in (WI) and wash-out (WO) indexes and ventilation ratio (VR=[WI-WO]/WI) maps generated by means of pixel-by-pixel analyses. Differences between pre- and postoperative WI (ΔWI), WO (ΔWO) and VR (ΔVR) were also determined. To determine the relationship between all ventilation index changes and pulmonary functional loss, Pearson's correlation was used to correlate each ventilation index change with the corresponding pulmonary functional parameter change. In addition, stepwise regression analysis was performed for all ventilation index changes and each corresponding pulmonary functional parameter change. Results: FEV₁/FVC% change showed fair or good and significant correlations with ΔWI (r = 0.39, p = 0.01) and ΔVR (r = 0.68, p = 0.001), %FEV₁ change good or moderate and significant correlations with ΔWI (r = 0.56, p = 0.0001) and ΔVR (r = 0.76, p < 0.0001), and %VC change moderate yet significant correlation with ΔWI (r = 0.65, p < 0.0001) and ΔVR (r = 0.67, p < 0.0001). Stepwise regression analysis demonstrated that FEV₁/FVC% change (r² = 0.56, p < 0.0001) significantly affected two factors, ΔVR (p < 0.0001) and ΔWI (p = 0.006), as did %FEV₁ change (r² = 0.68, p < 0.0001) [ΔVR (p < 0.0001) and ΔWI (p = 0.0001)], and %VC change (r² = 0.63, p < 0.0001) [ΔVR (p < 0.0001) and ΔWI (p = 0.0001)]. Conclusion: Inspiratory/expiratory Xe-enhanced ADCT has the potential to demonstrate that pre- and postoperative ventilation status of surgically treated NSCLC patients correlates with pulmonary function.