Preoperative And Postoperative Study Of Lung Volume Reduction Surgery And Lung Cancer Resection Using Quantitative CT

Objective To investigate the optimal VRT reconstruction threshold intervals usingmultislice spiral computed tomography (MSCT), by which target areas of LVRS are well displayed.Materials and methods 56 patients with scheduled LVRS were divided intogroup A (n = 10) and group B (n = 46). All cases underwent expiratory phase MSCT scan, reconstructed with 2.0mm thickness and soft tissue kernel. With reconstruction threshold intervals of -1024Hu～-960Hu and -1024Hu～-910Hu, respectively, VRT was applied to group A. The result VRT images using above two threshold intervalswere compared with axial and MPR images, concerning on the extent, location and display as well, in order to determine the optimal threshold intervals for target areas in LVRS. Then the determined threshold intervals of group A was applied to VRT reconstruction in group B. Counted and located bulla with diameters more than 3cm in the result VRT images, analyzed the emphysema distribution types, and compared with axial and MPR images. Use t- test to assess the difference of bulla counting results between VRT and two-dimensional images. The result VRT images were compared with operative findings in 14 LVRS patients.Results In group A, the distribution type of emphysema was markedly heterogeneous in 6 lungs, intermediately heterogeneous in 10 lungs and homogeneous in 4 lungs. VRT reconstruction threshold intervals of-1024Hu--960Hu was optimal in displaying the target areas in LVRS, with adequate contrast to normal tissue, well coincidence in the extent and location between VRT and two-dimensional images. In group B, the distribution type of emphysema was markedly heterogeneous in 20 lungs, intermediately heterogeneous in 58 lungs and homogeneous in 14 lungs. The distribution types of emphysema, counting and locating bulla in the result VRT images correlated well with source images (P>0.05). The result VRT findings of LVRS patients were verified in operation.Conclusion VRT reconstruction threshold intervals of -1024Hu--960Hu welldisplayed distribution types of emphysema and the target areas in LVRS, which becomes an arising method of preoperative evaluation and postoperative outcome prediction.Objective Comparing to pulmonary function testing (PFTs) results, discuss thevalue of quantitative CT (QCT) evaluation in patient selection for LVRS and postoperative outcome prediction.Materials and methods 10 emphysema patients who underwent LVRS weregiven lung spiral CT scan at 90%VC (vital capacity), 10%VC level and pulmonary function testing (PFTs) 1 week before and 3,6,12 months after operation, respectively. Quantitative analysis of 10 cases of pre- and post-operative CT images was performed. The indexes include total emphysema severity indexes (mean lung density, pixel index of emphysema, pixel index of severe emphysema) , emphysema heterogeneous index(standard deviation of mean lung density, full-width-at-half-maximum ), total lung volume,normal lung density volume and regional emphysema severity indexes(upper lung EPI, lower lung EPI, upper/lower EPI, upper lung SEPI and lower lung SEPI, upper/lower SEPI). Morphologic changes of thoracic cavity and diaphagram were measured in corresponding regions. Difference between pre- and post-operative PFTs results, CT quantitative indexes and changes of thoracic cavity and diaphagram were compared. The correlation between QCT indexes and PFTs results were analyzed.Results 1. PFTs results, QCT indexes and morphologic changes of thoracic cavityand diaphagram ameliorated after LVRS. There was significant difference between pre-and post-operative results (P<0.05) . The amelioration of postoperative values achieved peak ones on 6th month, then decreased progressively. The change tendency of QCT indexes and morphologic changes of thoracic cavity and diaphagram had in common with that of PFTs. 2. MLD, EPI correlated well with TLC and ventilation indexes of PFTs (P<0.05) . Upper lung EPI, lower lung EPI, upper lung SEPI and lower lung SEPI, upper/lower SEPI correlated well with TLC and, ventilation andresidual indexes of PFTs (P<0.05) . 3. 10%VC level quantitative analysis results correlated with PFTs results better than that of 90%VC.Conclusion QCT was applicable not only in screening before LVRS but alsoevaluating postoperative functional and morphological changes. MLD and regional emphysema severity indexes correlated well with PFTs results. 10%VC level quantitative analysis results correlated with PFTs results better than that of 90%VC. QCT was also a reliable method to evaluate the distribution types and extension of emphysema, both whole lungs and single side in LVRS. It was of great clinical value in preoperative screening and postoperative prediction in LVRS.Part II Study of Using of Quantitative CT to PredictPostoperative Pulmonary Function in Patientswith Lung CancerChapter I Usefulness of Quantitative CT to PredictPostoperative Pulmonary Function in Patientswith Lung CancerObjective The objective of this study is to assess the evaluation of quantitative CT used in predicting postoperative pulmonary function in patients with lung cancer. Materials and Methods 31 patients with lung cancer who underwent bothpulmonary functional tests and quantitative CT scan before operations were enrolled in this study. A postprocessing CT program was applied to quantitate the volume ofwhole-lung parenchyma with attenuation of -910Hu--600Hu, which was defined as total functional lung volume(TFLV). The volume of lung (lobes or segments) with attenuation of -910Hu - -600Hu was defined as regional functional lung volume(RFLV). FVC and FEV_1.0 were obtained from preoperative puhnonary functional tests. According to the formula: predicted FVC (pre-FVC)= preoperative FVC× (1- (RFLV/TFLV)) ; predicted FEV_1.0(pre-FEV_1.0) = preoperative FEV_1.0 × (1— (RFLV/TFLV)), we obtained values of predicted-FVC. predicted-FEV_1.0 predicted-FVC% predicted-FEV_1.0%- Use paired-t test and Pearson correlation test to assess the difference and correlation between CT-predicted values and postoperative measured results of FVC. FEV_1.0. FVC% and FEV_1.0%.Results The overall results showed a good correlation between the predicted valuesderived from QCT and the postoperative values from the conventional spirometry (r=0.87, 0.81, 0.85 and 0.81 for FVC, FEV_1.0, FVC% and FEV_1.0%, respectively, P<0.01). There was no significant difference between the predicted values by QCT and those determined by spirometry in terms of the puhnonary function (mean difference for FVC 0.18 L, FEV₁ 0.19 L, FVC% 5.0% and FEV₁% 7%, respectively).Conclusions Pre-operative quantitative CT, combined with spirometry can providecomparable data on postoperative lung function in comparison with postoperative spirometry; therefore, quantitative CT can serve as a useful tool to predict postoperative pulmonary function in patients with lung cancer.Chapter II Prediction of Postoperative Lung Function in Patients with Lung Cancer: Comparison Study among Quantitative CT,Perfusion Scintigraphy and Anatomical segmentation Objective To compare accuracy of QCT, perfusion scintigraphy and anatomicalsegmentation in predicting postoperative lung function in lung cancer patients. Materials and methods Pulmonary functional tests, quantitative CT scan andperfusion sintigraphy results in 12 cases before operations were analyzed. FVC, FEV_1.0 and DLco were obtained from preoperative pulmonary functional tests. A postprocessing CT program was applied to quantitate the volume of whole-lung parenchyma with attenuation of -910Hu- -600Hu, which was defined as total functional lung volume(TFLV). The volume of lung(lobes or segments) with attenuation of -910Hu--600Hu was defined as regional functional lung volume (RFLV). Regional and whole lung radioactivity counts (Qps%)was obtained from quantitative analysis results of perfusion sintigraphy. According to the corresponding formula for QCT, perfusion sintigraphy and anatomical segmentation method, values of predicted-FVC, predicted-FEV_1.0 and predicted-DLco were obtained. The difference and correlation between these predicted values and postoperative measured results of FVC, FEV_1.0 and DLco were assessed using paired-t test and Pearson correlation test. Bland-Altman analysis was used to test the concordance among predictive values of QCT, perfusion sintigraphy and anatomical segmentation method.Results QCT, perfusion sintigraphy and anatomical segmentation method predictivevalues significantly correlated with postoperative measured ones (FVC: r=0.87 0.80, 0.86; FEV_1.0: r=0.93,0.91 0.93; DLco: r=0.93 0.95,0.93, respectively; P<0.001). There was no significant difference between all the predicted values by three methods and those determined by spirometry in terms of the pulmonary function (P>0.05). Bland-Altman analysis indicated good concordance among these three methods in predicting postoperative lung function.Conclusion QCT, perfusion sintigraphy and anatomical segmentation method wereapplicable in predicting postoperative lung function. The predicted values showed accuracy in concordance with postoperative measured ones.