[Diagnostic value of (18)F-FDG PET/CT for solitary nodular-type bronchoalveolar carcinoma].

OBJECTIVE: To assess the value of (18)F-FDG PET/CT in the diagnosis of solitary nodular-type bronchoalveolar carcinoma (BAC). METHODS: The clinical and radiographic data were analyzed retrospectively in 30 patients with pathologically confirmed solitary nodular-type BAC who underwent (18)F-FDG PET/CT examinations between August, 2005 and December, 2006. The morphological and radioactive findings of the lesions were reviewed, and the maximum standard uptake values (SUVmax) were measured. The diagnostic accuracy of PET, PET/CT, and HRCT were analyzed. RESULTS: The (18)F-FDG SUV was markedly lower in BAC than in other well differentiated adenocarcinoma. In 19 of the BAC cases, PET showed a SUVmax of no less than 2.5, demonstrating positive changes. Of the total of 30 cases, 5 had ground glass opacity (GGO) changes, 3 exhibited mixed nodules with GGO changes around the lesions, and 22 cases presented with solid nodules. HRCT showed that BAC located often in the superior lobes of the bilateral lungs, mostly below the pleura in the surrounding lung field; the lesions were patchy or nodular with irregular shapes, showing lobulation in 22 cases, spiculation in 15 cases, pleural indentation in 21 cases, and vacuolar changes in 4 cases. The diagnostic accuracy of PET, PET/CT and HRCT for solitary nodular-type BAC was 36.67%, 93.33%, and 93.33%, respectively. CONCLUSION: The SUVmax of BAC provides only limited value for defining the nature of the lesions, but can serve as a general reference for assessing the disease activity. PET/CT, which allows both functional and imaging assessment, can be a valuable modality to reduce the misdiagnosis rate of BAC.

[Value of positron emission tomography-computed tomography in the diagnosis of mediastinal lymph node metastasis of non-small cell lung cancer].

OBJECTIVE: To investigate the value of positron emission tomographic-computed tomographic scanning (PET/CT) in the diagnosis of mediastinal lymph node metastasis in patients with non-small cell lung cancer and the application of PET/CT in the clinical staging of NSCLC. METHODS: A hundred and fifty-eight patients with NSCLC undergoing surgical resection and mediastinoscopy received preoperative examinations with PET/CT. All the patients underwent mediastinal lymph node dissection or sampling, and the pathological results were compared with the imaging findings. The diagnostic sensitivity, specificity, positive and negative predictive values, and accuracy of CT and PET/CT were compared. RESULTS: Final histology was available for 937 lymph node samples (N1, N2, and N3) from 158 patients during mediastinoscopy or surgical resection. The sensitivity, specificity, and positive and negative predictive values of CT for identifying mediastinal lymph node involvement were 51.0%, 76.1%, 49.0%, and 77.6%, respectively, with an diagnostic accuracy of 68.4%. The sensitivity, specificity, and positive and negative predictive values of PET/CT were 83.7%, 89.0%, 77.4%, and 92.4%, respectively, with a diagnostic accuracy of 87.3%. CONCLUSION: Mediastinoscopy is essential for patients with positive findings of mediastinal lymph node involvement by PET/CT, but might not be necessary in negative patients.