| Objective:Tumor heterogeneity is an inherent basic characteristic of malignant tumors. Early studies have shown that tumor microvascular architecture contributes to its phenotype heterogeneity. Estimation of this heterogeneity on single-slice CT perfusion imaging is an accurate assessment of the lung blood flow (BF).Literature also shows that increasing the scan Z-axis can reduce tumor heterogeneity on single-level CT perfusion imaging. Our hypothesis is that:the heterogeneity of blood flow within lung cancer nodules on Z-axis covering the complete nodule on volume perfusion CT imaging (VPCT) can reduce the influence of tumor heterogeneity on the results and assist in better diagnosis of lung nodules.Methods:We collected66cases from2011to2013cases with lung nodules. Of them58cases met the inclusion criteria of this study. Among them,39cases (67.2%) belonged to lung cancer group,10patients (17.2%) belonged to the inflammation group of and9cases belonged to tuberculosis group (15.5%). These58cases with pulmonary nodules underwent CT volume perfusion scanning. Post-processing, full nodule perfusion parameters were evaluated (BF, BV and PEI). Then the equatorial maximum level of nodules on Z-axis direction, using the2DMax analytic plane to2DMax levels, each nodules BF value as a single-level perfusion CT parameter was calculated on a level of3-7. Analysis of comparative VPCT for single level perfusion diagnostic performance on diagnostic CT of malignant pulmonary nodules was evaluated using the coefficient of variation of perfusion. Evaluation was done using CT tumor imaging on VPCT. On, VPCT and single-level perfusion CT, evaluation of lung nodules blood flow and differences in the evaluation of tumor imaging heterogeneity was assessed.Results:1) the VPCT single-level perfusion CT tumor and image heterogeneity difference:the lung group VPCT-BF value of33.17±11.77ml/100ml/min CV of35.5%in well-differentiated group the lung VPCT-BF is35.93±the13.86ml/100ml/min, CV for38.6%, poorly differentiated group the lung VPCT-BF value of29.79±11.11ml/100ml/min CV of37.3%. The lung cancer group2DMax-BF value of32.53±13.14ml/100ml/min CV was41.0%, the which the well differentiated lung cancer2DMax of-BF value of37.68±15.70ml/100ml/min, CV41.7%, poorly differentiated lung2DMax-BF value of27.32±11.02ml/100ml/min CV for40.3%, the lung cancer the group VPCT-BF the coefficient of variation were less than the coefficient of variation of2DMAX-BF (37.4%VS42.3%); group of well-differentiated and poorly differentiated group of two subgroups VPCT-BF coefficients of variation were less than the coefficient of variation of2DMAX-BF, it was respectively well-differentiated group (38.6%VS41.7%), poorly differentiated group (37.3%vs40.3%).2) VPCT single-level perfusion CT evaluation of lung nodules blood and flow difference:In the lung group VPCT-BF values were higher than the count of2DMax-BF value to a high value group, VPCT-BF value to less than2DMax-BF value of low group the high value the group VPCT-BF value was significantly higher than2DMAX-BF (31.06±9.38vs28.43±9.27ml/100ml/min, P=0.00); the low group VPCT-BF value was significantly lower than2DMax-BF value of37.37±15.05vs40.73±16.59ml/100ml/min, P=0.017).3) the heterogeneity of tumor imaging evaluation of lung nodule blood flow BF:nodules of the lung cancer group heterogeneity, quantitative evaluation of the blood flow differences in the level of each nodule size CV, results showed that in lung cancer CV group nodules minimum2.74%up to54.88%, with a median of10.35%,15.38%of malignant nodules CV greater than30%(6/39). The median CV for the sector, in the imaging of the lung cancer group is divided into nodules of homogeneous and heterogeneous nodules, regardless of the nodules imaging whether homogeneous, VPCT-BF, values were significantly higher than2DMax-BF value (homogeneous nodules:34.48±10.54ml/100ml/min VS32.06±10.49ml/100ml/min, P=0.004; the heterogeneity nodules:28.68±7.64ml/100ml/min vs26.01±7.62ml/100ml/min, P=0.000) and not significantly lower than2DMAX-BF value (P>0.05);2DMax-BF compared VPCT the median of-BF estimate the rate to be at10.17%.4) VPCT and single-level perfusion diagnostic performance of CT diagnosis of malignant pulmonary nodules:In the lung group VPCT-BF value was significantly lower than inflammatory group (33.17±11.77ml/100ml/min vs46.12±18.27ml/100ml/min, P=0.008), and significantly higher than tuberculosis group (33.17±11.77ml/100ml/min vs2.81±2.19ml/100ml/min, P=0.000), We refer to the past, the Philips16-story single-level perfusion threshold diagnosis of lung nodules:At a threshold of15<BF<60ml/ml/min, the VPCT hase no significant difference for the diagnostic performance malignant pulmonary nodules with the single-level CT perfusion, the sensitivity, specificity, accuracy, negative predictive value, positive predictive values were:95.4%,74.2%,70.5%,84.4,92.3%; The diagnostic performance of single-level perfusion CT, the sensitivity, specificity, accuracy, negative predictive value, positive predictive values were:95.4%,72.5%,70.5%,84.4,92.3%,VPCT can reduce the heterogeneity of the tumor and is better suited for the review of the patient as it has a better repeatability. Conclusion:1) mor imaging of blood flow in the evaluation of lung nodules BF, use the Z-axis to cover the complete nodule volume perfusion CT the imaging (VPCT) can reduce tumor heterogeneity influence on the results, tumor perfusion parameters more objective.2) the single-level perfusion CT ratio the VPCT tumor blood flow measured underestimated10%, the recommendations do not have to do the volume of perfusion conditions, or due to the larger tumors, can not do the volume perfusion, single-level perfusion value and underestimate the value of10%will be able to get an approximate value of the volume perfusion.3) The VPCT single-level diagnostic performance of perfusion no significant difference,VPCT can reduce the effects of tumor heterogeneity of perfusion parameters, and has better stability and better repeatability to review the patient. |
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