The Application Values Of Dual-energy CT Dual-energy Technology In The Diagnosis Of Colorectal Cancer

Part ⅠVirtual non-contrast and iodine values of colorectal diseases from flash dual-source CT: a clinical applicationObjective To assess the feasibility of the virtual non-contrast images from the Flash dual source CT applied in the diagnosis of colorectal diseases and iodine value measurement techniques in the identification of colorectal cancer normal intestinal from lesions, the feasibility of different degrees of differentiation of colorectal cancer in the application of colorectal cancer.Methods The85patients who were suspected clinically to have colorectal cancer underwent the true non-contrast, arterial and venous phase dual energy scan in the year between October2012and October2013. The virtual non-contrast CT images that were derived from the arterial and venous phase data using the Liver VNC software were compared with the true non-contrast. The CT values, the iodine value, standardized CT values, standardized iodine value were compared between normal and abnormal intestinal wall, among varying degrees of colorectal cancer.Results The radiation dose of two-phase dual-energy scanning was lower than the conventional three-phase scans. There was significant difference in the CT value of different kinds of images. The CT values of the livers and liver metastases were higher than the true non-contrast groups, however, the CT values of the intestinal lesions, metastasis lymph nodes, fat were lower than true scan. There was no statistical significance between virtual non-contrast groups. The difference of three groups of intestinal wall thickness in the lesions and metastasis lymph node size was not statistically significant. The noise of the true non-contrast images was higher than the virtual non-contrast images and the CNR, SNR were lower than the virtual non-contrast images. There was no difference between the two groups of virtual scan in noise, SNR and CNR. There was no significant difference among the three groups in image scores and the diagnostic coincidence rates. There was statistical significance between normal intestinal tumor lesions and tumor lesions in the CT values, the iodine value, standardized CT values, standardized iodine value. In the above parameters, the value of normal intestinal lower than tumor lesions. The diagnostic performance of iodine value was hinger than CT values,that was same to standardization compared non-standardization. There was no statistical significance among varying degrees of differentiation of colorectal cancer in the CT value, iodine, standardized CT values, standardized iodine value.Conclusion The virtual non-contrast images from the Flash dual source CT dual-source CT can be used to reduce the radiation dose in guarantee of the quality of the image and the diagnosis of the colorectal diseases. CT value, iodine value, normalized value CT, the iodine value can be normalized for normal bowel, colorectal cancer lesions determined, CT value, iodine value, normalized value CT standardized iodine value can be used to discriminate normal bowel from colorectal cancer lesions. The diagnostic value of iodine value is higher than CT performance. The standardization can improve the diagnostic performance of xenophobic confounding factors. Difference is not find among the iodine value, CT value of differentiation degree of different differentiation degree of colorectal cancer. Part ⅡOptimization effects of dual-source CT SAFIRE combined the Optimal CNR technique in the colorectal cancer image qualityObjective To investigate the value of dual-source CT sinogram affirmed iterative reconstruction(SAFIRE) and optimal contrast to noise ratio(Optimal CNR) technology in the optimization of image quality of colorectal cancer.Methods The research object was the same as the part one. The venous phase image quality, T staging accuracy were compared in the groups using filtered back projection(FBP), using FBP and Optimal CNR technology, using SAFIRE, using SAFIRE and Optimal CNR technology. The optimal value of keV of venous phase in colorectal cancer was obtained.Results The differences of four groups in the CT image values, noise, SNR, CNR and image score were statistically significant. The noise of group using SAFIRE group were lower compared with FBP group and CNR and the image score were higher. The situation was same to the group using Optimal CNR groups compared with group without using it. Group using SAFIRE and Optimal CNR had highest CT value, SNR, CNR, and the lowest noise. However, the T stage difference in4groups was not statistically significant. The best keV for venous phase of colorectal cancer was75kV.Conclusion Dual-source CT SAFIRE and Optimal CNR techniques can improve the image quality. The combination of the two technologies can improve image quality further. Part ⅢThe comparative analysis of the low kV, best contrast to noise ratio, iodine figure in the detection of liver metastases of colorectal cancerObjective To compare diagnostic for the colorectal cancer liver metastases value of the100kV. Sn140kV, fused image, optimal contrast image noise, iodine figure.Methods The research object is15cases of the patients from the first part who was found with liver low density which was confirmed of liver metastases by pathologically or the increase of the size later. There were67liver metastases. The quality of the image of100kV, Sn140kV, fused image, optimal contrast to noise ratio image were compared and the detection rate of liver metastases of colorectal cancer in100kV, Sn140kV, fused image, optimal contrast to noise ratio images, iodine figure.Results Statistically significant was not among the CT value of the four groups. The difference of noise100kV and Sn140kV with the maximum noise was not statistically significant. The rest of the group differences were statistically significant. The fused image had the minimum noise. There was no statistically significant among the detection for liver metastases which was smaller thanlcm2.The Sn140kV groups with the lowest detection rate, were statistically significant different with other groups. The rest groups’differences were not statistically significant. The detection rate of four groups for the liver metastases with the size1.1-2cm2and>2cm2was not statistically significant.Conclusion Low kV, the best CNR technology, linear fused image, iodine figure contribute to the detection of colorectal cancer liver metastases smaller thanlcm2.