Résumé
Objective To investigate the value of 18F-FDG SUVmax in gastric cancer diagnosis with coincidence imaging.Methods The coincidence imaging was performed in 92 patients with gastric diseases (60 males,32 females,age 65 (32-85) years; 78 malignant cases,14 benign cases).The malignant cases included 3 remnant gastric cancers and 75 primary gastric cancers (staging: 4 of Tis,13 of T1,9 of T2,33 of T3,11 of T4 and 5 without surgery).The well-,moderately-and poorly-differentiated adenocarcinomas were 22,15 and 28,respectively.Images were analyzed retrospectively with visual method and 18F-FDG SUVmax,and the diagnostic results were compared with the histopathological findings.The ROC curve was used to analyze the SUVmax.The Pearson's correlation analysis was performed to evaluate the relationship between SUVmax and tumor size.The Wilcoxon rank sum test was applied to determine the difference of SUVmax between early and advanced gastric cancers.The Kruskal-Wallis test was used to analyze the difference of SUVmax in various types of differentiated adenocarcinoma.Results No matter visual method or SUVmax was used,the sensitivity,specificity and accuracy of coincidence imaging in diagnosis of gastric cancer were 64.1％(50/78),64.3％(9/14) and 64.1％(59/92),respectively.The AUC of SUVmax was 0.695 and the cut-off value was 0.700.SUVmax Was positively correlated with tumor size significantly(r=0.489,P＜0.001).There was statistically significant difference between SUVmax of Tis-1 and that of T2-4(0.676± 1.288 vs 3.851 ±3.764;Z=-3.754,P＜0.001).However,there was no statistically significant difference among SUVmax of various grades of differentiated adenocarcinoma(2.805±4.008,3.447±2.365,3.413± 3.737 ; x2 =2.459,P＞ 0.05).Conclusions SUVmax provides more information than visual method in assessing gastric cancer with 18F-FDG coincidence imaging.Appropriate cut-off value of SUV is necessary for improvement of the diagnostic efficiency.Relationships between SUV and pathological T stage,histopathological types and differentiation degree need further investigation.