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Objective To investigate the predictability of occult lymph node metastasis (OLM) using metabolic parameters of pretreatment 18F-FDG PET-CT in squamous cell lung carcinoma patients manifesting clinical negative node (cN0).Methods A total of 91 cN0 squamous cell lung carcinoma patients who underwent curative surgery and pretreatment 18F-FDG PET/CT were enrolled retrospectively.Metabolic tumor volume (MTV) and total lesion glycolysis (TLG) of primary tumor were obtained with standardized uptake value (SUV) threshold of 2.5.ROC curve analysis was performed to quantify the predictive value of SUVmax,MTV,TLG and the maximal tumor length.To identify risk factors for OLM,univariate and multivariate Logistic regression analysis were performed.Results Of 91 patients,26 had OLM.Significantly higher SUV MTV,TLG and the maximal tumor length were observed in patients with OLM compared with negative occult lymph node metastasis (all P＜0.05).ROC curve showed that the cutoff point of SUVmax,MTV,TLG and the maximal tumor length were 12.76,31.17 cm3,153.13 and 3.8 cm,respectively.Univariate analysis showed correlation of tumor location (central),the maximal tumor length,SUVmax,MTV and TLG with the rate of OLM (all P＜0.05).In multivariate analysis,tumor location (central),the maximal tumor length ＞3.8 cm and MTV ＞31.17 cm3 showed association with increased risk of OLM (all P＜0.05).Conclusion MTV in 18F-FDG PET/CT is an independent factor for predicting OLM in patients with cN0 squamous cell lung carcinoma,which can be used to guide surgical planning.
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Purpose To analyze the 18F-FDG PET/CT features of small intestinal malignant neoplasm, and to discuss the diagnosis value. Materials and Methods Forty-seven patients who were highly suspected with small intestinal tumors underwent 18F-FDG PET/CT whole body scan were retrospectively analyzed, the results of PET/CT examinations and the findings of biopsy and surgical pathology were compared. The maximum of intestinal wall thickness (IWTmax) and maximum of standardized uptake value (SUVmax) were calculated to analyze the relationship of them under different pathological conditions. Results Six out of the 47 small intestinal tumors were benign, the other 41 were malignant tumors among which 19 were malignant lymphoma and 17 were adenocarcinoma. The sensitivity, specificity, accuracy rate, positive predictive value and negative predictive value of 18F-FDG PET/CT in the diagnosis of small intestinal malignant neoplasm were 92.7%, 83.3%, 91.5%, 97.4% and 62.5%, respectively. Compared with those of benign tumors, the SUVmax and IWTmax of malignant intestinal tumors were significantly higher (t=5.596 and 2.376, P0.05). The SUVmax and IWTmax of small intestinal malignant lymphoma had no correlation (r=0.293, P>0.05), whilst there was significant correlation between the IWTmax and SUVmax in small intestinal adenocarcinoma (r=0.542, P<0.05). Conclusion The SUVmax and IWTmax of malignant intestinal tumors are higher than those of benign intestinal tumors; 18F-FDG PET/CT imaging is rather reliable in differentiating small intestinal malignant tumors from benign ones. Intestinal malignant lymphoma shows a higher uptake of 18F-FDG than intestinal adencarcinoma, but the intestinal wall thickness of the two kinds shows no difference.