| Objectives:1.To explore the value of morphology characteristics in iodine maps with dual-energy CT to distinguish benign and malignant thyroid small nodules.2.To evaluate the value of quantitative parameters determination with dual energy CT enhancement scanning in the diagnosis of benign and malignant thyroid small nodules.3.Quantitatively evaluate the impact of nonlinear blending technology on image quality of PTMC.Methods:1.Choose 80 cases of patients whom’ had been verified with thyroid small nodule by surgical pathology,and they were scanned through dual-energy CT contrast scanning because of thyroid nodule.Respectively measure the CT values of internal carotid artery in arterial and venous phase,screen 100 nodules whose CT values satisfied for 146.5±40.4Hu in arterial phase,69.3±12.6Hu in venous phase(70 malignant nodules,30 benign nodules),and choose 30 cases for normal thyroid which had no lesion in CT image with pathology or thyroid tissue beside thyroid nodule in CT and no other disease in pathology.Compare the sensitive,the specificity,and the accuracy of diagnosing malignant nodule for morphologic characteristics between Iodine maps with regular imaging,which include "irregular shape","residual strengthen circle","segmental defect character".And evaluate the value of gravel-like calcification in plain scan to differentiate the benign and malignant nodules.Then,measure the iodine concentration and CT values among normal thyroid,malignant nodules,and benign nodules respectively in arterial,venous phase.And count normalized iodine concentration(NICnod),normalized CT value,spectrum curve slope(SCP),compare the differences of quantitative parameter among them.What’s more,analyze the diagnosis efficiency of them and combination of morphology characteristics with quantitative parameters.Calculate respectively total radiation dose in regular scan and dual-energy scan(triple radiation dose of regular plain scan represents total regular scan dose,radiation dose of associating regular plain scan with dual-energy double-phase scan represents dual-energy scan),evaluate that if it would increase the dose of neck scan with dual-energy scan.2.Choose 70 cases(80 lesions)of patients with PTMC whom were verified by surgical pathology,and all of them were performed dual-energy CT neck contrast scanning because of thyroid nodule.We would compare the CT values,SNR,CNR of thyroid lesions,normal thyroid,and carotid artery,between two groups of linear blending whose fusion coefficient is 0.3 and non-linear blending,and compare background noise(SD)of two group imaging.What’s more,compare the CT value difference of thyroid lesion and surrounding thyroid tissue between two groups.Two experienced radiologists perform subjective ratings for image quality and lesion display of two groups.Results:1.In arterial phase,the morphology of iodine maps had a higher sensitivity,specificity and accuracy than the conventional enhanced on diagnosis of PTMC(P<0.05).The diagnosis accuracy of "irregular shape","residual strengthen circle","segmental defect character"was irregular shape>residual strengthen circle = segmental defect character,and segmental defect character had a higher specificity than the others.ln venous phase,all morphologic characteristics of iodine map had a little higher sensitivity,specificity and accuracy than the conventional enhanced.But the sensitivity,specificity and accuracy of the two groups of image on diagnosis of PTMC were low.It observed the microcalcification distribution in plain scan images,the sensitivity,specificity and accuracy of "gravel-like calcification" on diagnosis of PTMC were 30%,100%and 51%respectively.In arterial phase,NICnod of PTMC,begin node,normal thyroid respectively is 0.318±0.149,0.305±0.125,0.602±0.147,normalized CT value among them is respectively 0.273±0.112,0.292±0.102,0.634±0.146,spectrum curve slope is 3.175±1.300,3.185±1.104,7.151±1.337.There is statistical significance of the values among three groups(P<0.05),there is also statistical significance between normal thyroid with begin or malignant nodes(P<0.05),but there is no significance between begin node with malignant node(P=0.236,0.377,0.083,P>0.05).In venous phase,normalized iodine concentration(normalized CT value)of PTMC,normal thyroid,begin node are respectively 0.619±0.196(0.636±0.213),0.859±0.121(0.880±0.152),0.723±0.102(0.741±0.114).There is statistical significance between two of them(P<0.05),NICnod and normalized CT value of begin and malignant node are lower than normal thyroid,also,NICnod and normalized CT value have a good consistency(Kappa=0.780、0.758,0.781、0.765).When the NICnod is 0.721 and the normalized CT value is 0.766 in venous phase,the areas under the ROI curve are 0.956,0.929,which has a 85%(90%)sensitive,80%(85%)specificity.Combine all morphologic characteristics in iodine maps with NICnod,normalized CT value,its sensitive,specificity and accuracy are respectively 91.24%、94.33%、92.01%.There is no statistical significance(P>0.05)between the regular scan with dual-energy double-phase scan respectively for CTDIvol values,DLP,and ED values.2.There is no statistical significance of background noise between two groups(P=0.64),while there is statistical difference for CT value of thyroid lesion,normal thyroid,carotid artery and sternocleidomastoid between two groups(P<0.05);furthermore,the value of group NLB is higher than group LB.And the CT value difference in NLB is higher than that in LB after enhanced scan(P<0.05).The CNR and SNR of thyroid lesion,normal thyroid and carotid artery in group NLB is higher than in group LB,which have statistical difference(all P<0.05).The subjective ratings for image quality in group NLB(3.66±0.73)are more than group LB(3.09±0.66)(P<0.05).Apparently,NLB improved the display of bounds and inside information in PTMC lesions.Conclusions:1.Dual-energy CT scan of thyroid nodules should include plain scan,arterial and venous phase scan.Plain scan image can observe the calcification,it can observe the nodular morphology change in arterial iodine maps,and it can measure the quantitative parameters in venous phase.2.It had a advantage for displaying the morphology characteristics of thyroid malignant small nodules on arterial iodine maps than that of venous iodine maps and conventional image.3.It had a certain value to measure standardization iodine concentration,standardized CT value,spectral curve slope of thyroid small nodules(small papillary thyroid carcinoma and nodular goiter)for identifying benign and malignant nodule.4.The combination of arterial morphology characteristics with venous NICnod,standardized CT value can improve the accuracy of qualitative diagnosis of thyroid nodules.5.The non-linear blending technology can improve the image quality of neck,which would be more distinct to display the boundary of PTMC,and it can be in favour of detection of PTMC. |
PDF Full Text Request