Objective To analyses the CT misdiagnostic causes of gallbladder carcinoma, in order to improve the diagnostic rate.Methods Fourty-three patients with the gallbladder carcinoma proved histologically were examined by computed tomography (CT), twenty-three of them were misdiagnosed.The misdiagnostic causes were analysed and compared CT images with operation.Results In the cases of misdiagnosis they were diagnosed as acute or chronic cholecystitis in 5; polyp in 1; bile duct carcinoma in porta hepatis in 2; cholangiocarcinoma in 1; neoplasm of distal part of common bile duct or ampulla in 3; carcinoma of head of pancreas in 5;cholangitis in 1; jaundice of obstruction in 2;tumefaction of gallbladder in 2;carcinoma of colon in 1. Conclusion To be aware of CT characters of gallbladder carcinoma and the way of metastasis is useful to avoid misdiagnosis of the gallbladder carcinoma and to improve the diagnostic rate.

Objective To evaluate the imaging feature of microcarcinoma of thyroid with CT.Methods CT findings of 50 lesions in 47 patients with microcarcinoma of thyroid ( dimeter,0.5 to 1.0 cm) were retrospectively analyzed.All of the patients had pathological diagnosis.Results Of the 50 lesions,38 lesions showed homogeneous low density on non-enhanced CT and various degree of enhancement on postcontrast CT. Thirty-three lesions showed discontinuous edge of the thyroids on non-enhanced CT. The boundary of 30 lesions became unclear on post-contrast CT relative to non-enhanced CT and the extension of low density of lesions decreased. Theshape of 31 lesions were irregular. Fifteen lesions showed calcifications,with granular calcifications in 13 lesions.Ten lesions were complicated with thyroiditis.Conclusions Irregular shape,discontinuous edge of the thyroids,the shrinkage of low density of lesions on post-contrast CT relative to non-enhanced CT,granular calcifications and multiple small lymph node around lesions indicate the diagnosis of microcarcinoma of the thyroid.It should be noted that thyroiditis can cover up microcarcinoma of thyroid.

Objective To assess the value of CT hyperenhancement sign in diagnosis and differential diagnosis of benign and malignant thyroid nodules.Methods CT findings of 2926 nodules in 1676 patients were retrospectively analyzed,among which 2174 nodules were benign and 752 nodules were malignant.All the patients had pathological diagnosis.The degrees of enhancement were divided into hyperenhancement and iso/hypoenhancement.The distribution of hyperenhancement in benign and malignant nodules were summarized.The sensitivity,specificity,positive and negative predictive value and accuracy of hyperenhancement for benign nodules and adenomatoid nodules were observed.Results Hyperenhancement was more common in benign nodules than in malignant nodules (10.3％ vs 0.7％,x2 =70.259,P ＜ 0.05),and its sensitivity,specificity,positive and negative predictive value and accuracy was 9.8％,99.5％,98.2％,27.6％ and 32.8％,respectively.Hyperenhancement was more common in adenomatoid nodules than in nonadenomatoid benign nodules (67.4％ vs 6.1％,x2 =525.025,P ＜ 0.05),and its sensitivity,specificity,positive and negative predictive value and accuracy was 67.4％,93.9％,41.6％,97.8％ and 92.3％,respectively.Conclusion Hyperenhancement sign is an important sign which can effectively differentiate benign nodules from malignant nodules,and adenomatoid nodules from nonadenomatoid benign nodules,and it is helpful for diagnosis of benign nodules and adenomatoid nodules.

Objective To evaluate the value of annular calcification in CT in the diagnosis and differential diagnosis for benign and malignant thyroid nodules.Methods CT findings of 67 nodules in 67 patients pathologically diagnosed with annular calcifications were retrospectively analyzed to identify 49 benign nodules and 18 malignant nodules.The interior or boundaries of annular calcification before and after contrast-enhancement were compared,and the degree of enhancements of both interior annular calcification and thyroid tissues were observed.After contrast-enhancement,the numbers of lesions showing clearer boundaries and higher degree of enhancement were summarized.Statistic analysis was conducted by using x2 test.Results Among 67 nodules with annular calcifications,clearer boundaries after contrast-enhancement were observed in 61.2％ (30/49) benign nodules and 16.7％ (3/18) malignant nodules,showing significant statistical difference (x2 =10.457,P ＜ 0.05).The sensitivity and specificity of clearer edge after contrast-enhancement for benign nodules were 61.2％ (30/49) and 83.3％ (15/18) respectively.Higher degree of enhancement were observed in 16.3％ (8/49) in benign nodules and 0(0/18) malignant nodules,showing no significant statistical difference (x2 =3.337,P ＞ 0.05).The sensitivity and specificity of higher degree of enhancement for benign nodules were 16.3％ (8/49) and 100.0％ (18/18) respectively.The combination of clearer boundaries and higher degree of enhancement after contrast-enhancement was observed in 77.6％ (38/49) benign nodules and 16.7％ (3/18) malignant nodules,showing significant statistical difference (x2 =20.549,P ＜ 0.05).Meanwhile,the sensitivity and specificity of such combination for benign nodules were 77.6％ (38/49) and 83.3％ (15/18) respectively.Conclusions CT is important in the diagnosis of thyroid nodules with annular calcification.Clearer boundary after contrast-enhancement and its combination with higher degree of enhancement are helpful for the diagnosis of benign nodules.Boundaries that similar to or more obscure than that of plain scan indicate malignant nodules.

Objective To investigate the diagnostic value of CT signs of ipsilateral central lymph node metastasis (ICLNM) in single papillary thyroid carcinoma (PTC) by multivariate regression analysis.Methods The CT data of 302 single PTC with diameter ＞1.0 cm confirmed by operation and pathology were retrospectively analyzed.The optimal thresholds of lymph node metastasis diameter were obtained by receiver operating characteristic (ROC) curve analysis.And multivariate regression analysis was used to analyze the relation between lymph node size,degree of enhancement,calcification or cystic degeneration,central turbidity,positive lateral cervical lymph nodes and the ICLNM positivity.Results In 302 PTC,the proportion of ICLNM positive and negative was 63.6％ (192/302) and 36.4％ (110/302),respectively.According to the ROC curve,with the increase of lymph node diameter,the sensitivity of diagnosing lymph node metastasis decreased and the specificity increased.When the threshold was 0.4 cm,Youden index was the largest (0.358),and the sensitivity and specificity was 50.5％ and 80.3％,respectively.Multivariate analysis showed that the diameter≥0.4 cm,high enhancement,central turbidity and lateral cervical lymph nodes positivity were the independent risk factors of ICLNM,and the OR values were 4.189[95％ CI (2.037-8.617)],3.875 [(95％ CI (1.561-9.617)],4.054[(95％CI (2.230-7.371)] and 8.735 [(95％ CI (1.093-69.831)],respectively.Calcification or cystic degeneration was not statistically significant in ICLNM.Conclusions The diameter ≥0.4 cm,high enhancement,central turbidity and lateral cervical lymph nodes positivity are the independent risk factors of ICLNM.Although calcification or cystic degeneration is not the independent risk factor,it has high accuracy for ICLNM positivity.The accurate identification of these signs can help surgeons to take a more thorough surgical treatment and has great significance to reduce postoperative recurrence.

Objective To investigate the predictive value of multiple CT signs in the diagnosis of benign and malignant thyroid nodules.Methods The CT data of 1 009 nodules with diameter >1.0 cm confirmed by histology from 931 patients was retrospectively analyzed, including 548 benign nodules from 484 patients and 461 malignant nodules from 447 patients.According to the inspection time, all nodules were divided into model group(2009—2014)and test group(2015—2016).The distribution of nodules with irregular shape, bite cake syndrome, micro calcification, enhanced range reduction/blur, cystic and high enhancement were evaluated in two groups.Univariate and multivariate logistic regression analysis were performed to evaluate the predicting value of multiple CT sighs for benign and malignant thyroid nodules in two groups.Results The numbers of benign and malignant nodules were 252 and 233 in model group,and were 296 and 228 in test group.The univariate logistic analysis of the model group and the test group showed that irregular shape, bite cake syndrome, micro calcification, enhanced range reduction/blur were more common in malignant nodules.OR values were 4.172 and 6.327,3.927 and 3.493,5.354 and 6.674, 11.814 and 5.082,8.680 and 14.562,respectively.The areas under the predicted probability curve were 0.946 and 0.936, respectively.The micro calcification was an independent predictive factor in the multivariate logistic regression analysis in the model group but not in the test group.Conclusion Irregular shape,bite cake syndrome and enhanced blur/range reduction are the CT signs of the stable malignant nodules,cystic and high enhancement are the CT signs of stable and benign nodules.Combination of multiple CT signs could improve the accuracy of diagnosis for Benign and Malignant Thyroid Nodules.

Objective To investigate the diagnostic value of lymph node size and distribution in ipsilateral central lymph node metastasis (ICLNM) of single papillary thyroid carcinoma (PTC) in CT examination.Method The CT data of 278 single PTC with diameter ＞ 1.0 cm confirmed by operation and pathology were retrospectively analyzed.According to the ipsilateral central lymph node diameter,these cases were divided into ＜ 0.2 cm group,0.2-0.4 cm group and ≥0.4 cm group,and the distribution difference of ICLNM positive and negative between the three groups were analyzed.Then according to the lymph node distribution,0.2 to 0.4 cm group were divided into turbidity group (≥ 3) and non-turbidity group (1-2),and ≥0.4 cm group were divided into cluster group (≥ 3) and non-cluster group (1-2).The differences betweeen turbidity group and non-turbidity group,cluster group and non-cluster group were analyzed.Results In 278 PTC,the proportion of ICLNM positive and negative was 65.8％(183/278) and 34.2％(95/278),respectively.ICLNM positive in ＜0.2 cm group,0.2-0.4 cm group and ≥0.4 cm group accounted for 37.3％ (31/83),68％ (66/97) and 87.8％ (86/98),respectively.x2 value and P value in between groups and within groups were 51.082 and 0,16.956 and 0,49.955 and 0,11.022 and 0.001,respectively.ICLNM positive in turbidity group and non-turbidity group accounted for 74.0％ (57/77) and 45％ (9/20),respectively.x2 value and P value were 6.151 and 0.013,respectively.ICLNM positive in cluster group and and non-cluster group accounted for 92.6％(50/54) and 82％(36/44),respectively.x2 value and P value were 2.619 and 0.106,respectively.Conclusions Among CT examination of patients with PTC,with the increase of the diameter and number of lymph nodes in central group,the positive proportion of ICLNM positive increases.For the 0.2-0.4 cm group,the turbidity phenomenon suggests that the possibility of metastasis is greater.The accurate identification of these signs can help surgeons take a more thorough surgical treatment and have great significance to reduce postoperative recurrence.