ABSTRACT
Objective To compare the diagnostic value 18F-fluorothymidine (FLT) and 18F-fluorodeoxyglucose (FDG) PET/CT in detecting lymph node metastases of untreated thoracic esophageal carcinoma. Methods Twenty-two patients with thoracic esophageal squamous cell carcinoma underwent both 18F-FLT and 18F-FDG PET/CT before surgery. The imaging results of the two modalities in detecting regional lymph node metastases were compared prospectively with the pathologic findings. The X2-test was used with SPS S 13.0. Results All patients underwent esophagectomy and lymphadenectomy. The metastatic lymph nodes were found in 16 patients, from which 47 of 424 excised nodes were positive by pathologic examination. False positive results were 14 while false negative 8 on 18F-FDG PET/CT. In contrast, false positive results were only 3 but false negative were 12 on 18 F-FLT PET/CT. The sensitivity, specificity, accuracy,negative predictive value, and positive predictive value were 74.47% ( 35/47 ), 99.20% ( 374/377 ),96.46% (409/424), 96.89% ( 374/386 ) and 92.11% ( 35/38 ) respectively for 18 F-FLT PET/CT, whereas the corresponding values were 82.98% (39/47), 96.29% (363/377), 94.81% (402/424), 97.84%(363/371 ) and 73.58% (39/53) respectively for 18 F-FDG PET/CT (X2 = 0.572, 6.018, 1.017, 0.348,3.852, P＞0. 05, ＜0.05, ＞0.05, ＞0.05 and ＞0.05). Conclusions Compared with 18F-FDG PET/CT, 18F-FLT PET/CT may be less sensitive but more specific for the detection of lymph node metastases of thoracic esophageal carcinoma.