Objective To explore the diagnostic performance and the distributive characteristics of me-diastinal lymph nodes in lung tumor with PET/CT examination .Methods Thirty-three cases of preoperative whole-body 18 F-FDG PET/CT examination revealed pulmonary lesions ,a radical surgery and lymph node dis-section patients were included in this study .PET/CT doctors read the image of PET/CT and recorded the lymph node short diameter,CT value,SUVmax,and analysed the patient′s visual graphics.The application of PET/CT a-nalysis was used for diagnosis of the mediastinal lymph nodes ,and compared with the pathological findings .Re-sul ts The diagnostic accuracy of mediastinal lymph nodes with the conventional CT method alone was 84 .1%, with the conventional PET method alone was 82.8%,with the conventional PET/CT analysis was 91.7%,with the PET/CT comprehensive analysis was 95.2%;Five benign lymph nodes were mis -diagnosed.In this study, there were eight cases of lung cancer with mediastinal or hilar lymph node metastasis ,all of the lymph nodes loca-ted in the right lung ,and in which five cases were in the inner zone .Conclusion The PET/CT comprehensive a-nalysis of lymph node performs better than either the CT method alone or the PET method alone (χ2 =9.10,P<0.05);The lesions in the inner zone are more prone to occur mediastinal lymph node metastasis .

Objective To investigate the diagnostic value of 18F-FDG PET/CT for thyroid nodules.Methods From January 2008 to May 2012,34 patients (13 males,21 females; age range:21-73 years,mean (53.00± 12.57) years) with thyroid nodules on 18 F-FDG PET/CT and with histopathological results were retrospectively analyzed.From January 2011 to December 2011,20 cases (9 males,11 females; age range:40-55 years,mean (45.00±4.72) years) were selected as control group.Wilcoxon rank sum test and ROC analysis (AUC ≥0.7 was considered the standard of medium-high accuracy) were used.PET/CT features taken to suggest malignant thyroid nodules were:focally high uptake on PET,indistinct boundary or heterogeneous density on CT with punctuate,round or curved calcifications,or with hypermetabolic cervical lymph nodes as ancillary supportive findings of metastasis.The sensitivity,specificity,positive predictive value,negative predictive value and accuracy of PET/CT for diagnosing thyroid nodules were calculated.Results (1) There were 18 patients with malignant and 16 with benign thyroid nodules.The SUVmax of benign,malignant nodules and normal controls were 7.59±8.69,5.75±4.48 and 1.38±0.57,respectively.The differences between malignant thyroid nodules and controls,between benign nodules and controls were significant (u=3.553,3.408,both P＜0.01).There was no significant difference between benign and malignant thyroid nodules (u =0.207,P＞0.05).(2) The AUC for the differentiation of benign and malignant thyroid nodules by ROC analysis was 0.557 (＜0.70).(3) The sensitivity,specificity,positive predictive value,negative predictive value and accuracy of 18F-FDG PET/CT for the differentiation of benign and malignant thyroid nodules were 72.2％ (13/18),75.0％ (12/16),76.5％ (13/17),70.6％ (12/17) and 73.5％ (25/34),respectively.Conclusions 18F-FDG PET/CT has limited value for the differentiation between benign and malignant thyroid nodules based alone on the degree of metabolic intensity.It may have improved diagnostic certainty if combined with the morphological features on CT.

Endometrial cancer is one of three major gynecological malignancies.When compared with the traditional imaging methods,PET/CT combines the characteristics of anatomy and molecular imaging.In this paper,we describe its advantages in detec-tion of metastatic lymph nodes,monitoring of disease recurrence and prognosis.The complementary effect is compared between PET and CT with MRI.With the development of new tracer and PET/MRI technology,the application of PET/CT is more extensive.

Objective Dual-source CT(DSCT) energy imaging was used to analyze the difference of energy spectrum pa-rameters and energy spectrum curves between mediastinal metastatic lymph nodes and non-metastatic lymph nodes in non-small cell lung cancer(NSCLC). The relationship between DSCT standardized iodine concentration and energy spectrum curve with medias-tinal lymph node metastasis was discussed. Methods A total of 113 patients with NSCLC underwent DSCT energy imaging scans. Io-dine images were obtained at the processing workstation. The normalized iodine concentrations of all mediastinal lymph nodes and en-ergy spectrum curves at different energy levels were measured. According to the pathological results,the patients were divided into lymph node metastasis group and non-lymph node metastasis group. The normalized iodine concentration and energy spectrum curve slope of the two groups were analyzed by t-test. The best threshold of standardized working iodine concentration was calculated by re-ceiver operating characteristic curve(ROC)to diagnose the mediastinal lymph node metastasis of NSCLC. Results There was a sig-nificant difference in the normalized iodine concentration between the two groups of mediastinal lymph nodes in NSCLC(P<0. 05);The ROC curve was used to calculate the standardized iodine concentration for the diagnosis of NSCLC. The optimal threshold for lymph node metastasis was 52. 45% ;The energy spectrum curve of mediastinal lymph nodes in NSCLC was gradually decreasing. There was a significant difference between the two groups in the range of 40~110 keV interval(P<0. 05). Conclusion The quanti-tative analysis of DSCT energy imaging parameters is of great significance in the diagnosis of mediastinal lymph node metastasis in NSCLC. It can be used as an important index for preoperative judgment of lymph node metastasis in NSCLC.