18F-FDG PET/CT显像鉴别腹腔积液性质的价值

目的 探讨18F-FDG PET/CT显像在不明原因腹腔积液患者积液性质鉴别诊断中的作用.方法 回顾性分析因不明原因腹腔积液入院的初诊患者70例,所有患者均行18F-FDG PET/CT 显像、同机CT平扫和腹腔积液细胞学检查,PET/CT显像计算病灶SUV.结果经组织病理学、腹腔镜、胃镜、肠镜等检查及临床随访确定,随访时间均大于6个月.对疑有胃肠道病变患者行PET/CT 延迟显像以明确诊断.有无腹膜转移组间SUVmax差异行两样本t检验；PET/CT、同机CT平扫及腹腔积液细胞学检查对腹膜转移诊断效能比较用McNemar检验；三者与最终结果吻合度检验用Kappa检验.结果 腹腔积液患者70例,经手术、腹膜活组织检查或腹腔积液细胞学检查证实48例为腹膜转移癌引起的恶性积液,22例为良性积液.2组腹膜的SUVmax分别为6.08±3.92和2.66±1.74,差异有统计学意义(t=-5.063,P＜0.001).PET/CT诊断45例为恶性积液,其中2例为假阳性,另有5例恶性积液被误诊为良性积液,PET/CT诊断腹膜转移的灵敏度、特异性和准确性分别为89.6％ (43/48)、90.9％ (20/22)和90.0％ (63/70).定位CT诊断27例为腹膜转移,其中4例为假阳性,CT 准确诊断良性腹腔积液18例,另有25例假阴性；定位CT诊断腹膜转移的灵敏度、特异性和准确性分别为47.9％ (23/48)、81.8％ (18/22)和58.6％ (41/70).PET/CT与定位CT诊断腹膜转移的灵敏度差异有统计学意义(x2=14.286,P＜0.001).70例腹腔积液患者中仅21例腹腔积液中见癌细胞,其余患者细胞学检查均为阴性,腹腔积液细胞学对腹膜转移诊断的灵敏度、特异性和准确性分别为43.8％ (21/48)、100％ (22/22)和61.4％ (43/70)；PET/CT与细胞学检查对腹膜转移诊断的灵敏度差异有统计学意义(x2=13.885,P＜0.001).PET/CT检查结果与最后诊断结果吻合度较强(Kappa=0.776,P＜0.001),定位CT、腹腔积液细胞学检查结果与最后诊断结果吻合度均较弱(Kappa值分别为0.236和0.328,P均＜0.05).结论 18F-FDG PET/CT显像对不明原因腹腔积液患者腹膜转移诊断有重要临床价值,可用于不明原因腹腔积液的良恶性鉴别诊断.

Value of 18F-FDG PET/CT in differentiating the character of ascites

Objective To assess the value of PET/CT in differentiating the character of ascites in patients with ascites of undetermined origin. Methods A total of 70 patients with aseites of undetermined origin were analyzed retrospectively. Each patient underwent a whole body mSF-FDG PET/CT scan, serum tumor marker examination and cytological examination of ascites. The diagnosis of peritoneal careinomatosis was established based on the results of histopathology examination, multimodality imaging and clinical follow-up after more than 6 months. T-test, McNemar test and Kappa test were used to analyze the data. Resuits Forty-eight patients were proven to have malignant ascites caused by peritoneal carcinomatosis accoming to histopathology examination, and the rest were proven to have benign aseites. The SUVmaX of peri- toneal lesions in the malignant ascites group and benign ascites group were 6.08±3.92 and 2.66±1.74, respectively （t = - 5. 063, P 〈 0. 001 ）. PET/CT lead to accurate diagnosis in 43 patients with malignant ascites and in 20 patients with benign ascites. False-positive and false-negative results were found in 2 and 5 patients, respectively. The sensitivity, specificity and accuracy of PET/CT for diagnosing peritoneal carci- nomatosis were 89.6% （43/48）, 90.9% （20/22） and 90.0% （63/70）, respectively. Located CT analysis accurately diagnosed 23 patients with malignant ascites and 18 patients with benign ascites. False-positive and false-negative diagnosis occurred in 4 and 25 patients, respectively. The sensitivity, specificity and ac- curacy of located CT for diagnosing peritoneal carcinomatosis were 47.9% （23/48）, 81.8% （18/22） and 58.6% （41/70）, respectively. The diagnostic sensitivities between PET/CT and located CT were signifi- cantly different （X2 = 14. 286, P 〈 0.001 ）. The cytological examination results were positive in 21 patients with malignant ascites. The diagnostic sensitivity, specificity and accuracy of cytological examination were 43.8 % （21/48 ）, 100% （22/22） and 61.4% （43/70）, respectively. The diagnostic sensitivity of PET/CT was higher than that of cytological examination （X2 = 13. 885, P 〈 0.001 ）. There was good agreement be- tween the diagnosis using PET/CT and the final diagnosis （Kappa =0.776, P 〈0. 001 ）. However, the agreements between the diagnosis using located CT or cytological examination and the final diagnosis were poor （Kappa = 0. 236 and 0. 328, both P 〈 0.05 ）. Conclusion is F-FDG PET/CT may help in diagnosing peritoneal carcinomatosis in patients with ascites of undetermined origin, and it can be used to differentiate the character of ascites.