The Application Of Spectral Computer Tomography In The Diagnosis Of Colorectal Tumor

Objective: To investigate the value of parameters of iodine concentration(IC),water concentration,normalized iodine concentration(NIC),spectral curve slope K,and effective atomic number(EAN)in the differential diagnosis of preoperative T,N stage of colorectal cancer,and its value in differential diagnosis between colorectal adenoma and adenocarcinoma with the methods of gemstone spectral imaging(GSI),inorder to provide a new method for the clinical preoperative diagnosis of colorectal tumorMaterials and Methods: We retrospectively analyzed the images of 39 patients with suspected colorectal lesions underwent routine abdominal pelvic and GSI bi-phase scanning from March 2017 to December 2017 in our hospital,including 23 males and 16 females,aged 41-82 years,mean age 62.5 years old,the median age of 63 years.22 lesions were located in the rectum,16 in the sigmoid colon,5 in the right colon,and 1 in the ileocecal region.A total of 44 lesions including 11 adenomas,33 colorectal lesions.15 cases of colorectal cancer were with lymph node metastasis;12 cases as early stage(T1-2)group,21 cases as advanced stage(T3-4)group.All subjects underwent spectral CT double-phase scanning to select the measurement area at the spectral image post-processing station,and measured and calculated the IC,water concentration,NIC,slope of the spectral curve,EAN.The independent sample t-test was used to compare the difference of spectral parameters between adenocarcinoma and colorectal adenoma,different T stage and N stage of colorectal cancer.The receiver operating characteristic curve(ROC curve)was used to evaluate the diagnostic efficacy of each spectral parameter.Results:(1)Comparison of spectral imaging parameters of colorectal adenoma group and adenocarcinoma group: Compared with adenoma group,adenocarcinoma group showed that IC,EAN,NIC,the slope of spectral curve in arterial phase,IC and NIC in venous phase were higher than adenoma group.The statistical analysis showed that P <0.05,the difference was statistically significant.There was no significant difference between adenoma and adenocarcinoma in water concentration in arterial phase,water concentration,EAN and the slope of spectral curve of venous phase.The statistical results showed that p> 0.05;(2)Comparison of spectral imaging parameters of different T stage of colorectal cancer: The IC,EAN,NIC and the slope of spectral curve of arterial phase in the advanced stage(T3-4 stage)group were higher than those of early stage(T1-2 stage)group,and the statistical analysis showed that P <0.05,and the difference was statistically significant.The water concentration in arterial and venous phase,IC,NIC,the slope of spectral curve,EAN in venous phase of early and advanced groups showed no significant difference,the statistical results showed that p> 0.05;(3)Comparison of spectral parameters of colorectal cancer with or without lymph node metastasis: The IC,EAN,NIC,the slope of spectral curve of arterial phase and IC of venous phase in lymph node metastasis group were higher than those of no lymph node metastasis group,the statistical analysis showed P <0.05,and the difference was statistically significant.There was no significant difference between lymph node metastasis group and non-lymph node metastasis group in the water concentration in arterial phase,and EAN,NIC and slope of spectral curve in venous phase,the statistical results showed that p> 0.05;(4)The diagnostic efficiency of each spectral parameter: The areas under the curve of IC,EAN,NIC,the slope of spectral curve in arterial phase,IC,NIC in venous phase in differentiating colorectal adenoma and adenocarcinoma were 0.778,0.727,0.823,0.764,0.778,0.702.15.13(100ug/ml),8.33,0.14,2.12,17.17(100ug/ml),0.40 as the threshold,the sensitivity of diagnosis was 66.7%,97.0%,87.9%,63.6%,69.7% and 97.0% respectively,the specificity was 88.9%,44.4%,77.8%,88.9%,77.8% and 44.4% respectively,and the Youden index were 0.556,0.414,0.657,0.525,0.475,0.414 respectively,of which the NIC in arterial phase has higher diagnostic efficiency than others.The area under the curve of IC,EAN,NIC,slope of spectral curve in arterial phase in assessing early and advanced stage of colorectal cancer were 0.812,0.756,0.783,0.831,respectively.16.24(100ug/ml),8.59,0.18,2.18 as the threshold,the diagnostic sensitivity were 69.6%,69.6%,60.9%,73.9%,respectively;the specificity were 88.9%,77.8%,88.9%,77.8%;and the Youden index were 0.585,0.474,0.498,0.517.The IC and the slope of spectral curve in arterial phase have higher diagnostic efficiencyThe area under the curve of IC,EAN,NIC,the slope of spectral curve in arterial phase and IC in venous phase in assessing colorectal cancer with or without lymph node metastasis were 0.831,0.825,0.754,0.833 0.712;15.50(100ug/ml),8.71,0.17,2.12,20.47(100ug/ml)as the threshold respectively,the diagnostic sensitivity was 92.9%,71.4%,85.7%,92.9%,64.3% respectively,and the specificity was 61.1%,83.3%,72.2%,61.1%,94.4%,Youden index were 0.540,0.547,0.579,0.540,0.587.Among them,the IC and the slope of spectral curve in arterial phase have higher diagnostic efficiency.Conclusion: 1,IC,EAN,NIC,and the slope of spectral curve in arterial phase,IC and NIC in venous phase have certain distinguishing significance on colorectal adenoma and adenocarcinoma.Among them,the NIC in arterial phase has high diagnostic efficiency;2,IC,EAN,NIC and slope of spectral curve in rterial phase have some value for distinguishing colorectal cancer from early group and advanced group,and the diagnostic efficiency of IC and slope of spectral curve in arterial phase is higher.3,IC,EAN,NIC,slope of spectral curve in rterial phase and IC in venous phase have some value in the assessment of colorectal cancer with or without lymph node metastasis.Among them,the IC and the slope of spectral curve in arterial phase has a higher diagnostic efficiency.