Objective To explore the relationships between ¹⁸F-FDG PET/CT imaging and morphology of postoperative recurrence of cardia cancinoma at the anastomotic stoma.Methods PET/CT and CT imaging data of fifty-two patients with postoperative recurrence, who had been confirmed by endoscopy, surgery and pathological examination, was collected and compared.Results Among the fifty-two patients,¹⁸F-FDG PET/CT imaging found no uptake in 3 cases(5.77%,3/52), but found uptake in the other 49 cases (94.23%,49/52). Among these 49 cases, there was patchy uptake in 14 cases(26.92%,14/52),nodular uptake in 19 cases(36.54%,19/52),and annular uptake in 16 cases(30.77%,16/52. CT imaging showed no obvious anastomotic wall thickening in 4 cases(7.69%,4/52), but mild thickening in 7 cases(13.46%,7/52), eccentric thickening in 19 cases(36.54%,19/52),and annular thickening in 22 cases(42.31%,22/52). There were significant correlations between PET/CT and CT in morphological classification (r=0.943,P<0.001).The semi-quantitative standardized uptake value (SUV_max、SUV_mean) of patchy uptake on 18F-FDGPET/CT imaging was relatively lower than that of morphological and overall uptake, and there was significant difference between them(P<0.01).There was no significant difference between PET/CT and CT imaging in the accuracy rate of clear or suspicious diagnosis or in the rate of failure to diagnose postoperative recurrence(86.54%,45/52 versus 78.85%,41/52; 13.46%,7/52 versus 21.15%,11/52, χ²=13.48, P=0.063), but there was difference in diagnosis between no uptake, patchy uptake and nodular uptake, annular uptake in PET/CT imaging(χ²=27.25, P=0.017, P<0.05). PET/CT imaging failed to diagnose postoperative recurrence in 3 cases of no uptake and 4 cases of patchy uptake, compared to 4 cases of no obvious anastomotic wall thickening and 7 cases of mild thickening by CT imanging.Conclusions Postoperative recurrence of cardia cancinoma at the anastomotic stoma is difficult to diagnose in cases of no or patchy uptake in ¹⁸F-FDG PET/CT imaging, but the rate of diagnostic accuracy can be improved when anastomotic thickness and morphology in CT imaging are combined.