Combination of FDG PET/CT and contrast-enhanced MSCT in detecting lymph node metastasis of esophageal cancer.

BACKGROUND: Lymph node metastasis is believed to be a dependent negative prognostic factor of esophageal cancer. To explore detection methods with high sensitivity and accuracy for metastases to regional and distant lymph nodes in the clinic is of great significance. This study focused on clinical application of FDG PET/CT and contrast-enhanced multiple-slice helical computed tomography (MSCT) in lymph node staging of esophageal cancer. MATERIALS AND METHODS: One hundred and fifteen cases were examined with enhanced 64-slice-MSCT scan, and FDG PET/CT imaging was conducted for neck, chest and upper abdomen within one week. The primary lesion, location and numbers of metastatic lymph nodes were observed. Surgery was performed within one week after FDG PET/CT detection. All resected lesions were confirmed histopathologically as the gold standard. Comparative analysis of the sensitivity, specificity, and accuracy based on FDG PET/CT and MSCT was conducted. RESULTS: There were 946 lymph node groups resected during surgery from 115 patients, and 221 were confirmed to have metastasis pathologically. The sensitivity, specificity, accuracy of FDG PET/CT in detecting lymph node metastasis were 74.7%, 97.2% and 92.0%, while with MSCT they were 64.7%, 96.4%, and 89.0%, respectively. A significance difference was observed in sensitivity (p=0.030), but not the others (p>0.05). The accuracy of FDG PET/CT in detecting regional lymph node with or without metastasis were 91.9%, as compared to 89.4% for MSCT, while FDG PET/CT and MSCT values for detecting distant lymph node with or without metastasis were 94.4% and 94.7%. No significant difference was observed for either regional or distant lymph node metastasis. Additionally, for detecting para-esophageal lymph nodes metastasis, the sensitivity of FDG PET/CT was 72%, compared with 54.7% for MSCT (p=0.029). CONCLUSIONS: FDG PET/CT is more sensitive than MSCT in detecting lymph node metastasis, especially for para-esophageal lymph nodes in esophageal cancer cases, although no significant difference was observed between FDG PET/CT and MSCT in detecting both regional and distant lymph node metastasis. However, enhanced MSCT was found to be of great value in distinguishing false negative metastatic lymph nodes from FDG PET/CT. The combination of FDG PET/CT with MSCT should improve the accuracy in lymph node metastasis staging of esophageal cancer.

[The value of dual time point 11C-choline PET-CT in differentiating malignant from benign lesion of mediastinum].

OBJECTIVE: To evaluate the value of dual time point 11C-choline PET-CT in differentiating malignant from benign lesions of mediastinum. METHODS: Thirty-five patients with mediastinal diseases, including 8 non-small cell lung cancer or highly suspected lung cancer patients with mediastinal lymphadenectasis, were subject to CT, dual time point PET-CT and videomediastinoscopy within four weeks. 11C-choline was used as PET tracers to visualize various masses. The imaging protocol included the first PET scanning 5-10 min after the-injection of 370 MBq 11C-choline and then a second PET scanning 25-30 min later. The PET data were evaluated using the standardized uptake value (SUV) and the difference between the two point (DeltaSUV). Then the results were analyzed in accordance with the pathologic data. RESULTS: Eleven of the 35 patients with mediastinal diseases were diagnosed as with sarcoidosis, 6 with tuberculosis, 5 with lymphoma, 11 with nodal metastasis (8 had their modes from the lung and the primary lesions of the other 3 failed to be identified), and 2 with lung cancer with reactive hyperplasia lymph node. The SUV of the delayed images of the 16 malignant lesions was 6.48 (3.0-11.2), higher than that of the early images [6.17 (3.2-9.8)] with a DeltaSUV of 0.31 (-0.4-1.4). The value of SUV of delayed images of the 19 benign lesions was 4.99 (2.2-9.3), lower than that of early images [5.11 (2.9-8.3)] with a DeltaSUV of -0.12 (-0.9-1.0). The DeltaSUV of the benign lesions was significantly lower than that of the malignant lesions (F = 1.939, P = 0.04). The accuracy rates of diagnosis of mediastinal masses of CT, first-time PET-CT, dual time point PET-CT, and videomediastinoscopy were 54.3% (19/35), 74.3% (26/35), 82.9% (29/35), and 100% (35/35) respectively. Conclusion With a high diagnostic yield, videomediastinoscopy remains the gold standard in differentiation of malignant and benign lesions located in the middle mediastinum. Dual time point PET-CT may improve the accuracy.

The role of 11C-choline positron emission tomography-computed tomography and videomediastinoscopy in the evaluation of diseases of middle mediastinum.

BACKGROUND: Middle mediastinal masses comprise a wide variety of tumors but may also reflect lymphadenopathy, and thus remain an interesting diagnostic challenge. We performed positron emission tomography (PET) of mediastinal masses in order to evaluate the ability of PET to predict the malignancy of these tumors. We compared histologic findings, videomediastinoscopy, computed tomography (CT), and PET-CT in patients with mediastinal disease. METHODS: Thirty-two patients were evaluated with CT, PET-CT and videomediastionoscopy, and all studies were performed within four weeks in each patient. (11)C-choline as a PET tracer was used to visualize masses. PET data were evaluated using the standardized uptake value (SUV) and were compared with pathologic data. RESULTS: There were 13 men and 19 women aged from 21 to 74 (mean 45.2) years. Among the patients with mediastinal diseases, sarcoidosis was diagnosed in 12 patients, tuberculosis in 5 patients, lymphoma in 5 patients, and noncaseating granulomata without classical "sarcoid" finding in 3 patients. N2 or N3 nodal metastasis was revealed in 6 of 7 patients who had non-small cell lung cancer or suspected lung cancer, and one was negative (the pathological diagnosis was reactive hyperplasia). The accuracies for correctly diagnosing mediastinal masses for CT, PET-CT and videomediastinoscopy were 38% (12/32), 63% (20/32), and 91% (29/32) respectively. The diagnostic accuracy of videomediastinoscopy was superior to that of PET-CT (chi(2) = 11.130, P < 0.001). The SUVs were similar among these diseases. On the other hand, if the diagnostic classification was benign vs malignancy, the accuracies for CT, PET-CT and videomediastinoscopy were 53% (17/32), 75% (24/32), 100% (32/32) respectively. The diagnostic accuracy of videomediastinoscopy was superior to that of PET-CT (chi(2) = 22.042, P < 0.001). The SUV of malignant lesions (6.9, 3.2 - 9.8; n = 11) appeared to be higher than that of benign lesions (4.9, 2.9 - 8.3; n = 21), however, this difference was not statistically significant (P = 0.054). CONCLUSIONS: To diagnose lesions located in the middle mediastinum, videomediastinoscopy possesses the highest diagnostic accuracy, and therefore remains the gold standard. PET-CT is valuable for differential diagnosis of benign vs malignant lesions, CT alone or PET alone (SUV) may provide misdiagnosis in a substantial proportion of patients with mediastinal masses.

[Clinical evaluation of 18F-FDE PET-CT in detecting malignant liver tumors].

OBJECTIVE: To evaluate the clinical value of (18)F-fluorodeoxyglucose ((18)F-FDG) positron-emission tomography (PET) combined with computer tomography (PET-CT) in the diagnosis and clinical staging of liver cancer. METHODS: (18)F-FDG PET-CT was performed preoperatively in 16 cases of primary and 8 metastatic liver cancers. The imaging features of the primary foci were analyzed, followed by measurement of standardized (18)F-FDG uptake. For the metastatic foci, the abnormal metabolism of (18)F-FDG was observed and CT, PET and PET-CT fusion images were obtained for accurate localization of these foci. RESULTS: (18)F-FDG uptake occurred in the supraclavicular region in 6 (37.5%) of the 16 patients with primary liver cancer, but was detected in the 8 patients with metastatic liver cancer. Fourteen metastatic nodules were found in 5 of the 16 patients with primary liver cancer, located in the lungs (2 cases) or the abdominal cavity (3 cases). CONCLUSIONS: Negative results of (18)F-FDG PET-CT imaging should be carefully evaluated for diagnosing primary liver cancers, considering the very low sensitivity (37.5%) of this imaging modality in this study. But in the cases of metastatic liver cancers this imaging modality may exhibit high sensitivity, and can also be of great value in clinical staging of the primary liver cancers.