RESUMO
Objective To investigate the features of PET-CT manifestation of pancreatic metastasis,and to improve its detection rate.Methods The PET-CT images of 31 cases of clinically diagnosed pancreatic metastases and 26 cases of primary pancreatic cancer were retrospectively evaluated.Two experienced specialists identified the lesion location in fused images.After frame by frame image analysis,the lesions with significantly increased radioactivity uptake were seen as positive,when compared with surrounding normal pancreatic tissue.The outline of regions of interest was drawn along the edge of the lesion shown in PET,and based on a semi-quantitative evaluation,the maximum standard uptake value (SUVmax) was calculated.If SUVmax ＞ 2.5,it was considered as positive.Results Among the 31 cases with pancreatic metastasis,22 cases of lung cancer,2 cases of gastric cancer 2 cases of colon carcinoma,1 case of maxillary sinus carcinoma,thyroid carcinoma,melanoma,renal cell carcinoma or gallbladder carcinoma were identified.Twenty-one cases (67.7％) were single,10 cases (32.3％) were multiple or diffuse lesions.Among the single lesions,7 (33.3％) were located in the pancreatic head and neck,14 in pancreatic body and tail.Among the 26 cases of primary pancreatic carcinoma,18 cases (69.2％) were located in the pancreatic head,8(30.8％) in the pancreatic body and tail.The sites of primary and metastatic pancreatic cancer were significantly different (x2 =6.012,P =0.014).CT scan showed only 17 nodular lesions with relatively low density and less clear boundary.PET images showed lesions in 31 cases of metastatic pancreatic cancer,and the mean SUVmax was 7.42 ± 3.48,which was significantly higher than that in primary pancreatic cancer group (5.39 ± 1.71,F =4.87,P =0.032).In addition,PET-CT identified 30 cases of other organs or lymph node metastasis.Conclusions PET-CT plays an important role in the diagnosis of metastatic pancreatic cancer.