The Application Of Contrast-enhanced MDCT Combined With FDG PET/CT In Esophageal Cancer Staging

Objective:To investigate the clinical application of contrast-enhanced multiple-slice helical computed tomography(MDCT) combined with FDG PET/CT in esophageal cancer staging.Methods:79 patients with esophageal cancer underwent MDCT and FDG PET/CT before surgery within one week from October 2005 to October 2008.The primary tumor, adjacent structures invasion,the locations and numbers of metastasis to individual lymph node groups were observed.The examination results of FDG PET/CT,MDCT and the both of FDG PET/CT and MDCT(the combined study) were analyzed blindly by three experienced nuclear medicine and radiology physicians.All the lesions were confirmed histopathologically.The results of MDCT,FDG PET/CT and combined study were compared with histopathology results which were golden standard.The sensitivity,specificity,accuracy,positive predictive value and negative predictive value of PET/CT,MDCT and PET/CT combined with MDCT were calculated. McNemar test was used to analyze the difference between MDCT and MDCT combined with PET/CT,between PET/CT and MDCT combined with PET/CT. Significance was set at P values＜0.05.Statistical software(SPSS,Version 13.0; SPSS Inc.)Results:Esophagectomy was performed in all 79 patients,84 primary tumors(squamous cell carcinoma 78,adenocarcinoma 4,carcinoid 1) were found.The primary tumor was done correctly by MDCT in 78.3%(P＜0.05),by PET/CT in 96.4%,and by the combined study in 96.4%.For T4 staging tumor,the sensitivity for MDCT,FDG PET/CT and the combined study was 70.0%,90.0%and 90.0%,respectively;the specificity was 94.5%,68.5%and 98.6%,respectively;the accuracy was 91.6%, 71.1%and 97.6%,respectively.The difference in specificity(P=0.0) and accuracy (P=0.0)between PET/CT alone and the combined study of MDCT and PET/CT were statistically significant.122 lymph node groups were confirmed pathologically having metastases among 538 lymph node groups in 79 patients.For detecting lymph nodes metastases the sensitivity for MDCT,FDG PET/CT and the combined study was 69.7%(85/122),86.1%(105/122),94.3%(155/122),respectively;the specificity was 95.7%(398/416),97.1%(404/416),98.6%(410/416),respectively;the accuracy was 89.8%(483/538),94.6%(509/538),97.6%(525/538),respectively;the positive predictive value was 82.5%(85/103),89.7%(105/117),95.1%(115/121),respectively; and the negative predictive value was 91.5%(398/435),96.0%(404/421),98.3% (410/417),respectively.The difference in sensitivity(P=0.0),specificity(P=0.003),accuracy(P=0.0),positive predictive value(P=0.003)and negative predictive value (P=0.0)between MDCT alone and the combined study were obviously;the difference in sensitivity(P=0.021),accuracy(P=0.004) and negative predictive value (P=0.041)between PET/CT alone and the combined study were obviously;the others were not(P＞0.05).Conclusion:FDG PET/CT is more sensitive than MDCT for detecting primary tumor and lymph node metastases;while MDCT had superior T4 staging diagnosis ability over PET/CT in our study group.The diagnosis and the staging of oesophageal cancer can be improved by using both of FDG PET/CT and MDCT at the same time.