| PartⅠ:The value of quantitative parameters of spectral CT in diagnosis of differentiation of lung adenocarcinomaObjective To explore the value of quantitative parameters of spectral CT in the differentiation of lung adenocarcinoma with different differentiation degrees.Methods This study included fifty-six patients with adenocarcinoma proved by pathology underwent chest plain and enhanced CT scan with gemstone spectral imaging(GSI),including 18 cases of poorly differentiated group,32 cases of moderately differentiated group and 6 cases of highly differentiated group.All the cases were divided into two groups of poorly differentiated group(18 cases of poorly differentiated adenocarcinoma)and moderately or highly differentiated group(38 cases,including 32 cases of moderately differentiated adenocarcinoma and 6 cases of highly differentiated adenocarcinoma).The slope between 40 and 60 keV(K)of spectral attenuation curve,effective atomic number(Eff-Z)and CT number in plain scan(PS)and K of spectral attenuation curve,iodine concentration,water concentration,CT number and normalised iodine concentration(NIC)in arterial phase(AP)and venous phase(VP)of poorly differentiated group and high-grade group were measured and compared respectively.The two-sample t test was used to compare quantitative parameters of poorly differentiated group and moderately or highly differentiated group.The correlations between spectral CT parameters and different differentiation degrees of lung adenocarcinoma were evaluated using the Spearman rank correlation analysis.ROC curves was drawn for these parameters with statistical difference and area under the curve(AUC)was used to measure the differential diagnostic performance of each parameter.Results The K and Eff-Z in PS,IC and NIC in AP and K,IC and NIC in VP of moderately or highly differentiated group were significantly higher than those in poorly differentiated group(all p<0.05).Comparison of quantitative parameters of spectral CT in PS:K and Eff-Z of moderately or highly differentiated group were 1.11±0.74、7.84±0.21,respectively.The corresponding parameters of poorly differentiated group were 0.33±0.19、7.36±0.42,respectively.Comparison of quantitative parameters of spectral CT in AP:IC and NIC of moderately or highly differentiated group were(1.47±0.61)mg/cm3,0.14±0.05,respectively.The corresponding parameters of poorly differentiated group were(1.03±0.30)mg/cm3、0.10±0.03,respectively.Comparison of quantitative parameters of spectral CT in VP:IC,NIC and K of moderately or highly differentiated group were(1.99±0.62)mg/cm3、0.36±0.12、8.24±2.23,respectively.The corresponding parameters of poorly differentiated group were(1.32±0.26)mg/cm3、0.26±0.07、4.66±1.73,respectively.The difference between moderately or highly differentiated group and poorly differentiated group was statistically significant(P<0.01).There was a significant positive correlation between spectral CT parameters(K and Eff-Z in PS,IC and NIC in AP and IC,NIC and Kin VP)and pathological grades by the Spearman rank correlation(r value were 0.596,0.715,0.371,0.420,0.570,0.435 and 0.635,respectively,all p<0.001).ROC curve analysis showed that these quantitative parameters in PS were helpful in differentiating moderately or highly differentiated group and poorly differentiated group,especially Eff-Z in PS.The AUC for it was 0.94.When 7.65 was selected as a threshold value for Eff-Z in PS,the sensitivity,specificity,PPV and NPV were88.9%,86.8%,76.2%and 94.3%,respectively.Conclusion Moderately or highly differentiated group and poorly differentiated group have different quantitative parameters in spectral CT imaging.These quantitative parameters are valuable in diagnosis of differentiation of lung adenocarcinoma.Part Ⅱ:Correlation between tumor size of adenocarcinoma and blood volume in lung evaluated by spectral CT quantitative parametersObjective To investigate the relationship between tumor size and blood volume in lung evaluated by spectral CT quantitative parameters.Method Seventy-four patients with lung adenocarcinoma proved by patholoy underwent chest plain and enhanced CT scan with spectral imaging mode.According to the diameter of the tumor,they were divided into three groups:24 cases in the ≤2cm group,22 cases in the 2cm-3cm group,and 28 cases in the>3cm Group.The net CT value,water concentration,iodine concentration and standardized iodine concentration of the three groups were measured respectively.The above data were tested for normal distribution and homogeneity of variance.The data satisfying the normal distribution and the variance were compared by one-way ANOVA.The two-sample corrected t-test was used when the variance was not uniform.A non-parametric test is performed on a non-normal distribution.Correlation analysis between tumor size,gender,age and spectral parameters was performed using Spearman correlation coefficient analysis.Results<2cm group,2cm-3cm group and>3cm group had different iodine related parameters(iodine concentration and standardized iodine concentration)and water concentration,the difference was statistically significant,and with the increase of tumor diameter,the iodine concentration parameter showed a downward trend,water concentration parameter upward trend.There were differences between the three groups of net CT enhancement values,but the difference was not statistically significant(p>0.05).Spearman correlation analysis showed that the correlation coefficient between tumor size and iodine related parameters(iodine concentration and standardized iodine concentration)was:-0.608,-0.575 in arterial phase,p<0.05 and-0.667,-0.716 in venous phase,respectively.<0.05.Spearman correlation analysis showed that the correlation coefficient between tumor size and water concentration was:0.593 in arterial phase,0.724 in venous phase,p all<0.05.There was no significant correlation between net CT enhancement value and tumor size,p>0.05.Conclusion Spectral CT can quantitatively analyze the blood volume of lung adenocarcinoma.There is a negative correlation between iodine concentration and tumor size,and positive correlation with water concentration.There was no significant correlation between net CT enhancement value and tumor size. |
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