[Low-dose spiral CT versus standard dose CT in detection of pulmonary metastasis from gestational trophoblastic tumor].

OBJECTIVE: The purpose of this study is to investigate whether low-dose spiral chest CT scan can replace standard-dose CT scan in detecting pulmonary metastases for patients with gestational trophoblastic tumor (GTT). METHODS: Totally, 34 GTT patients underwent 56 chest CT scans for the assessment of pulmonary metastasis. All patients received CT examination both at standard-dose (120 KV, 150 mAs, pitch 1, and a standard reconstruction algorithm) and low-dose CT (120 KV, 40 mAs, pitch 2, and a bone reconstruction algorithm) simultaneously each time. The images were interpreted by two radiologists independently. A metastasis by CT image was defined as a nodule within lung parenchyma that could not be attributed to a pulmonary vessel. The number of lesions detected at each dose protocol was recorded. The size of each lesion was measured and categorized as < 5 mm, 5 - 10 mm or > or = 10 mm. The differences in detection of the lesions between the standard- and low-dose CT protocols were compared using Wilconxon signed rank test. RESULTS: 1417 lesions were detected at the standard-dose, whereas 1214 lesions were found by low-dose CT. Lesions < 5 mm detected by low-dose CT were fewer than that detected by standard-dose CT (Z = -3.368, P = 0.000), though there was no statistically significant difference between the standard- and low-dose CT in detecting lesion > or = 5 mm (Z = -0.055, P = 0.957). Moreover, the risk score of the patients was not affected either. The sensitivity of low-dose CT was 69.16% for all size of lesions, 58.50% for < 5 mm, 87.07% for 5 - 10 mm, and 97.01% for > or = 10 mm. The positive predictive value for different sizes of lesion was 80.71% (all sizes), 73.82% (5 mm), 88.86% (5 - 10 mm), and 98.48% (> or = 10 mm), respectively. CONCLUSION: Low-dose chest CT can replace the standard-dose chest CT as a screening and follow-up examination to assess the change in pulmonary metastasis for patients with gestational trophoblastic tumor.

[Value of computed tomography in the staging and predicting resectability of primary advanced ovarian carcinoma].

OBJECTIVE: To assess the value of computed tomography( CT) in the staging and predicting respectability of primary advanced ovarian carcinoma. METHODS: The data of preoperative abdomen and pelvis CT scan in 64 women with Stage II or IV ovarian carcinoma were collected from tumor registry database. All CT scans were analyzed retrospectively without knowledge of the operative findings, and the stage as based on CT was compared with the surgical and pathological findings. Residual lesion of < or = 2 cm in maximal diameter was considered as an optimal surgical result. Twenty-senven of these 64 patients (42.2%) underwent optimal cytoreduction surgery for residual disease C2 cm in diameter. Based on the ability of each parameter in predicting cytoreductive surgery outcome, 11 radiographic features were selected for the final model. Each predictive parameter was assigned a numeric value (1 to 7). Sensitivity, specificity, positive predictive value( PPV) , negative predictive value( NPV),and accuracy were calculated for each predictive parameter. Receiver operating characteristic( ROC) curve was used to assess the ability of the model to predict surgical outcome. The correlation between CT stage and surgical-pathologic stage was analyzed by Chi-square test and Spearman's rho analysis. RESULTS: The overall accuracy of CT staging for advanced ovarian carcinoma was 87. 5% ; 86. 5% and 91.7% for stage III and IV patients respectively. The correlation between CT stage and surgicopathologic stage was found to be comformable. In the final predictive index model, when a predictive index scoreed > or = 2, the overall accuracy, sensitivity and specificity was 70. 3% , 67.6% and 74. 1% for identifying patients for suboptimal surgery. The PPV and the NPV was 78. 1% and 62. 5% , respectively. The ROC curve was generated with an area under the curve = 0. 792+/-0. 055 using the predictive index scores. CONCLUSION: CT has a high accuracy in staging and a moderate ability to predict resectability for advanced ovarian carcinoma. Therefore, the predictive index model may be useful in the management of ovarian carcinoma patients.