| Objectives 1 To investigate the accuracy of CT energy spectrum imaging in predicting preoperative pathological differentiation of colorectal cancer patients.2 To evaluate the preoperative lymph node metastasis of colorectal cancer by CT energy spectrum imaging.3 The homology of primary lesion and metastatic lymph node of colorectal cancer was discussed by using CT energy spectrum curve slope.Methods A retrospective analysis was performed on 82 patients diagnosed with colorectal cancer by preoperative colonoscopy or surgical pathology in our hospital from September 2019 to November 2021.The patients were scanned by energy spectrum imaging with GE Revolution CT scanner to obtain energy spectrum images in arterial and venous phase.The Protocols General module of GSI Viewer software in GE ADW4.7post-processing workstation was used to measure CT values of lesions and lymph nodes in arterial and venous stages within the single energy range of 40kev-140kev.Calculate the slope of the energy spectrum curve（λ）between 40kev-90kev single energy CT values,λ=(CT value 40kev-CT value 90kev)/50;Regions of interest（ROI）were placed at the lesions and lymph nodes on iodine-based maps and water-based maps in arterial and venous phases,respectively.Measurement of Iodine concentration（IC）,Water concentration（WC）,Effective atomic number（Eff-Z）.The normalized iodine concentration（NIC）was calculated by using ROI measurement IC at the same layer aorta as a reference.NIC=IClesion/ICco-layered aortic.Record the single energy CT value of 40kev-140kev and spectrum parameters（WC,IC,NIC,λ,Eff-Z）.According to the pathological results,they were divided into middle and high differentiation group and low differentiation group;According to whether the lymph node is metastatic or not,they were divided into lymph node metastasis group and non-lymph node metastasis group.According to the above-mentioned groups,the independent sample t-test was performed for 40kev-140kev single energy CT values and each energy spectrum parameter.The energy spectrum parameters with statistical significance were analyzed by Logistic regression.Furthermore,the statistically significant parameters were analyzed by joint Logistic regression to obtain the joint prediction probability.Plot the receiver operating characteristic curve（ROC）to compare the area under curve（AUC）,threshold,sensitivity,specificity,and Yoden index.The intraclass correlation coefficient（ICC）was used to analyze the consistency of the slope of energy spectrum curve between primary lesions and lymph nodes in patients with arterial and venous colorectal cancer lymph node metastasis.Results 1 Single energy CT value and energy spectrum parameter analysis and diagnostic efficiency evaluation of colorectal cancer with different degrees of differentiation in arterial and venous phase:1)Arterial phase:The single energy CT values of 40kev-140kev and WC,IC,NIC,λand Eff-Z were analysis in 62 cases of middle and high differentiation group and 20 cases of low differentiation group.The results showed that there were significant differences in 40kev-140kev single energy CT values between the two groups（all P<0.05）,and the single energy CT values of 40kev-140kev in low differentiation group were higher than those in middle and high differentiation group.There were statistical differences in IC,NIC andλbetween the two groups（all P<0.05）.IC,NIC andλin the low differentiation group were higher than those in the medium and high differentiation group.Univariate Logistic regression analysis of IC,NIC andλshowed that IC and NIC had statistical differences（all P<0.05）,butλhad no statistical difference（P>0.05）.Therefore,the joint prediction probability of IC and NIC was obtained by combined Logistic regression analysis.Drawing ROC curve and compare the AUC of single energy CT value,IC,NIC and the combination of IC and NIC.Except 140kev,the results show that the AUC of 40kev-130kev single energy CT value is in the range of 0.7-0.8,which has a medium level of diagnostic efficiency.The AUC of IC and NIC is 0.800and 0.828,and the threshold are 16.5μg I/m L and 0.18,respectively,and the diagnostic efficiency of NIC is better than IC.The maximum AUC of IC combined with NIC was0.850,which showed the highest diagnostic efficiency for colorectal cancer at different degrees of differentiation in arterial phase.2)Venous phase:Two groups of 40kev-140kev single energy CT value and WC,IC,NIC,λ,Eff-Z analysis showed that there were significant differences in 40kev-130kev single energy CT value and IC,NIC,λ,Eff-Z（all P<0.05）.The results of univariate Logistic regression analysis of IC,NIC,λand Eff-Z were statistically different（all P<0.05）.Therefore,the joint prediction probability is obtained by joint Logistic regression analysis of IC,NIC,λand Eff-Z.Draw ROC curve and compare the AUC of single energy CT value,energy spectrum parameters and joint parameters.The results showed that the AUC of 40kev-90kev single energy CT value was more than 0.8,it indicated that 40kev-90kev single energy CT value have a good predictive effect on the differentiation degree of colorectal cancer.The AUC of IC,NIC,λand Eff-Z were 0.927,0.882,0.859 and 0.863;The optimal thresholds were 22.38μg I/m L,0.58,3.23and 8.90;The single AUC of each parameter is more than 0.8.It has better diagnostic efficacy in judging the differentiation degree of colorectal cancer,and the efficiency of IC and NIC is better.The maximum AUC of IC andλis 0.934 when the two parameters are combined;The maximum AUC of IC,NIC andλis 0.942 when the three parameters are combined;The highest AUC of the combination of four energy spectrum parameters is0.943.3)Compared with arterial phase,the 40kev-90kev single energy CT value and energy spectrum parameters of venous phase,especially IC,NIC and four energy spectrum parameters combined,are more effective in predicting different differentiation of colorectal cancer.2 Single energy CT value and energy spectrum parameter analysis and diagnostic efficiency evaluation of lymph nodes in arterial and venous phase of CRC:1)Arterial phase:The analysis of 40kev-140kev single energy CT value and WC,IC,NIC,λ,Eff-Z between 31 cases of lymph node non-metastasis group and 27 cases of lymph node metastasis group showed that there were significant differences in 40kev-140kev single energy CT values between the two groups（all P<0.05）,and the CT value of lymph node non-metastasis group was higher than that of lymph node metastasis group.There were significant differences in IC,NIC,λand Eff-Z（all P<0.05）,and the values of all parameters in the non-metastasis group were higher than those in the metastasis group.Further Logistic regression analysis showed that there were significant differences in IC,NIC,λand Eff-Z（all P<0.05）.Therefore,the joint prediction probability was obtained by combined Logistic regression analysis of IC,NIC,λand Eff-Z.Draw ROC curve to evaluate single energy CT value,energy spectrum parameter and combined parameter AUC shows that 40kev-100kev single energy CT value AUC is 0.881,0.889,0.875,0.865,0.847,0.834,0.815,respectively,all more than 0.8.It indicated that 40kev-100kev single energy CT value has a good diagnostic efficiency for lymph node metastasis around colorectal cancer,and lymph node metastasis can be predicted by lymph node CT value.The AUC of IC,NIC,λand Eff-Z were 0.865,0.873,0.843 and 0.829;The optimal thresholds were 18.08μg I/m L,0.22,2.07 and 8.68;The single AUC of each parameter is more than 0.8.It has a good diagnostic efficacy in judging the metastasis of lymph nodes around colorectal cancer.The maximum AUC of NIC andλis 0.885 when the two parameters are combined;The maximum AUC of IC,NIC andλis 0.885 when the three parameters are combined;The highest AUC of the combination of four energy spectrum parameters is 0.884.2)Venous phase:The two groups of 40kev-140kev single energy CT value and WC,IC,NIC,λ,Eff-Z analysis showed that there was significant difference in single energy CT value（all P<0.05）,and the CT value of non-metastatic lymph node group was higher than that of metastatic group.There were significant differences in IC,NIC,λand Eff-Z（all P<0.05）,and the values of parameters in the non-metastasis group were higher than that of metastasis group.Logistic regression analysis showed that there were significant differences in IC,NIC,λand Eff-Z（all P<0.05）,so the joint prediction probability was obtained by combined Logistic regression analysis.Draw ROC curves showed that the CT values of 40kev-90kev were 0.845,0.851,0.853,0.838,0.823 and0.801,all more than 0.8.It indicates that 40kev-90kev single energy CT values has a good diagnostic efficiency for lymph node metastasis around colorectal cancer,and lymph node metastasis can be predicted by lymph node CT value.The AUC of IC,NIC,λand Eff-Z are 0.796,0.786,0.822 and 0.727,respectively,and the optimal thresholds are 19.89μg I/m L,0.47,2.76,9.13,respectively.The AUC of each single parameter is greater than0.7.It has moderate diagnostic efficacy in judging lymph node metastasis around CRC,andλis the best.The maximum AUC ofλand Eff-Z is 0.839 when the two parameters are combined;The maximum AUC of NIC,λand Eff-Z is 0.840 when the three parameters are combined;The highest AUC of the combination of four energy spectrum parameters is0.839.3)Compared with the venous phase,the single energy CT value and energy spectrum parameters of 40kev-100kev in the arterial phase,especially IC,NIC,NIC combined withλ,have better diagnostic effective in evaluating whether lymph nodes have metastasized.3 Analysis of homology of primary lesions and metastatic lymph nodes in arterial and venous phase of colorectal cancer with metastatic lymph nodes by energy spectrum curve slope:Consistency analysis of intraclass correlation coefficient（ICC）of energy spectrum slope of 27 cases of primary lesion group and lymph node metastasis group showed that the ICC in arterial phase was 0.955,the ICC in venous phase was 0.948,and the slope of energy spectrum curve in arterial and venous phase was more than 0.8.The results indicated that there was a strong consistency between the slope of energy spectrum curve of primary lesion and lymph node in arterial and venous phase,suggesting that metastatic lymph node had homology with primary lesion of colorectal cancer.Conclusions 1 Energy spectrum CT imaging 40kev-140kev single energy CT value and energy spectrum parameters IC,NIC,λ,Eff-Z have high value in predicting the differentiation degree of colorectal cancer,especially in venous phase 40kev-90kev single energy CT value and energy spectrum parameters IC,NIC and the combination of IC,NIC,λand Eff-Z has higher diagnostic value.2 Energy spectrum CT imaging 40kev-140kev single energy CT value and energy spectrum parameters IC,NIC,λ,Eff-Z have high value in predicting lymph node metastasis around colorectal cancer,especially in arterial phase40kev-100kev single energy CT value and energy spectrum parameters IC,NIC and the combination of NIC andλhas higher diagnostic value.3 The slope of energy spectrum curve has high predictive value in judging the homology between primary lesions and metastatic lymph nodes of colorectal cancer.Figure 12;Table 22;Reference 94... |
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