^(18)F-FDG PET显像对胰腺良恶性病变鉴别诊断的作用

The role of ^(18)F-FDG PET for differentiating malignant from benign lesions in the pancreas

目的 探讨18F 脱氧葡萄糖 (FDG)PET显像对胰腺良恶性病变鉴别诊断的价值。方法临床疑胰腺病变患者 30例 ,其中胰腺恶性肿瘤 2 0例 :胰腺癌 15例 ,胰腺癌切除术后复发 3例 ,低恶性胰岛细胞瘤、癌肉瘤各 1例 ;胰腺良性病变 10例 ,均为慢性胰腺炎 ,其中 3例并假性囊肿形成。除8例慢性胰腺炎为临床、放射学随访 3～ 12个月外 ,余均由组织病理学检查证实。静脉注射18F FDG2 2 2～ 2 96MBq 1h后行PET显像。测定肿瘤体积和标准摄取值 (SUV) ,并与PET检查前 2周内CT(2 5例 )、MRI(8例 )结果对照。结果 2 0例胰腺恶性肿瘤中 19例肿瘤明显摄取18F FDG ,平均SUV 4 91±3 6 5。 10例慢性胰腺炎中 9例病灶轻度或无摄取18F FDG ,平均SUV 1 70± 1 12 (t=2 6 9,P =0 0 12 )。4例肿瘤病灶直径≤ 3cm ,SUV 2 75± 0 6 3;6例 3 1～ 5cm ,SUV 4 5 9± 3 0 6 ;10例 >5cm ,SUV 5 4 6±2 2 9(χ2 =9 0 2 ,P =0 0 11)。 1例PET假阳性为慢性胰腺炎并假性囊肿 ,SUV 4 82 ;1例PET假阴性为胰头癌术后复发 ,病灶SUV 2 1。以SUV 2 5为胰腺良恶性病变的判断阈值 ,18F FDGPET显像诊断胰腺癌灵敏度、特异性和准确性分别为 95 0 %、90 0 %、93 3%,明显高于CT(75 0 %、5 5 6 %、6 8 0 %,χ2 =5 89,P =0 0 15 )。结论?

Objective To investigate the role of PET with 18 F-fluorodeoxyglucose (FDG) for differentiating malignant form benign lesions in the pancreas. Methods 18 F-FDG PET imaging was performed on 30 patients including 20 cases with pancreatic malignant tumors (15 adenocarcinoma,1 low malignant islet cell tumor,1 carcinosarcoma,and 3 patients with recurrent tumor after resection of primary pancreatic adenocarcinoma),and 10 cases with chronic pancreatitis (pancreatic pseudocysts were found in 3 of them). The final diagnosis was obtained by pathologic ( n = 22) and clinical or radiologic follow-up lasted 3～12 months ( n =8). PET findings were compared with the results of abdominal CT( n =25) and/or MRI( n =8) done within 2 weeks. Fasting blood sugar levels were controled in 3.9～5.9 mmol/L in all patients at first,then 222～296 MBq of 18 F-FDG was intravenously injected,the transmision and emission scan were performed 1 h after injection. The images of FDG PET were analyzed visually and semiquantitatively using standard uptake value (SUV). Results Nineteen of twenty patients with malignant tumors (95.0%) showed increased FDG uptake with a SUV of 4.91±3.65,and 9 of 10 patients with chronic pancreatitis (90%) showed low FDG uptake with a SUV of 1.70±1.12 ( t =2.69,P =0.012<0.05). There was 1 false-positive PET (pancreatic pseudocyst,SUV 4.82)and 1 false-negative PET (recurrent adenocarcinoma,SUV 2.1). Tumors ≤3 cm in diameter were of SUV of 2.75±0.63( n =4),3.1～5 cm,of SUV of 4.59±3.06( n =6),and >5 cm,of SUV of 5.46±2.29( n =10,χ 2=9.02,P =0.011). Using a cut-off value of >2.5 for the SUV,the sensitivity,specificity and accuracy for diagnosing pancreatic malignant tumors using FDG PET were higher than that of abdominal CT (95.0%,90.0% and 93.3% versus 75.0%,55.6% and 68.0%,respectively,χ 2=5.89,P =0.015). Conclusion 18 F-FDG PET is a sensitive and specific noninvasive technique for diagnosing pancreatic disorders.