PET与增强CT同机融合检查在胰腺恶性肿瘤鉴别诊断及临床分期中的价值

Value of （18）F-FDG PET/CECT in differential diagnosis and clinical staging of pancreatic cancer

目的探讨18^F—FDGPET与增强CT（contrastenhanceCT，CECT）同机融合（PET／CECT）检查对胰腺恶性肿瘤鉴别诊断及分期的应用价值。方法对52例未行过增强CT检查、临床及影像检查发现可疑胰腺病变的患者行常规PET／CT检查，同时在PET延迟扫描后立即行同机增强CT检查（PET／CECT），将两者图像融合并对胰腺病变进行诊断及鉴别诊断。以病理及临床随访结果作为诊断标准，比较PET／CECT、常规PET／CT对胰腺恶性肿瘤诊断的敏感性、特异性及准确性。分别测定病灶早期及延迟的最大标准摄取值（SUVmax），计算18F—FDG的滞留指数（RI）。以接受手术的24例患者术中所见及病理诊断为依据，比较PET／CECT与常规PET／CT对胰腺癌TNM分期的准确性。结果52例胰腺病变患者中，PET／CECT对胰腺良、恶性病变鉴别诊断的敏感性、特异性及准确性分别为100％、88．2％、96．2％，常规PET／CT分别为94．3％、70．6％、86．5％。恶性组（35例）的早期SUVmax、延迟SUVmax、R1分别为8．4±3．4、10．1±4．3、（24．1±22．6）％，良性组（17例）分别为4．5±3．9、5．0±4．3、（10．9±14．9）％，胰腺良、恶性组间RI差异无统计学意义（P=0．064）。24例手术患者中17例为恶性，PET／CECT和PET／CT诊断胰腺恶性肿瘤T分期准确性为82．3％和64．7％，差异有统计学意义（P=0．032）；诊断胰腺恶性肿瘤N分期准确性为91．7％和83．3％，差异无统计学意义（P=0．980）。结论18^F-FDGPET／CECT诊断胰腺良、恶性病变的敏感性、特异性及准确性优于常规PET／CT，判断胰腺恶性肿瘤侵犯周围血管及脏器的准确性高于常规PET／CT，可以作为一站式检查对胰腺病变行良、恶性鉴别诊断及术前评估。

Objective To investigate the values of （18）F-FDG PET integrated with contrast enhance CT（CECT） in the differential diagnosis and staging of pancreatic cancer. Methods Routine PET/CT was performed in 52 patients with clinically and radiologically suspected pancreatic lesions who had never undergone enhanced CT scan. After routine PET/CT exams, CECT was immediately performed （PET/CECT）, and the images of the two examinations were integrated for the diagnosis and differential diagnosis of pancreatic lesions. Pathological and follow-up results were used as golden standard, and the sensitivity, specificity and accuracy for PET/CECT and PET/CT in diagnosis of pancreatic cancer were evaluated. The early maximum standard uptake value （SUVmax） and delayed SUVmax were measured, and the retention index （RI） was calculated. In 24 patients with surgical operation and pathological results, the accuracy of PET/CECT and PET/CT in TNM staging of pancreatic cancer were compared. Results The sensitivity, specificity and accuracy of PET/ CECT in diagnosing pancreatic diseases were 100% , 88.2% , 96.2% , while those of PET/CT were 94.3%, 70.6% , 86.5%. In 35 malignant cases, the early SUVmax, delayed SUVmax and RI values were 8.4 ±3.4, 10.1 ± 4.3 and （ 24.1± 22.6） % , respectively. In 17 benign cases, the corresponding values were 4.5 ±3.9, 5.0 ± 4.3 and （ 10.9± 14.9 ） %, respectively. There were no significant differences of the RI values between malignant and benign lesions （P =0. 064 ）. Seventeen of 24 patients underwent surgery were diagnosed to have pancreatic cancer, the diagnostic accuracy of PET/CECT and PET/CT for T staging was 82.3% and 64.7% （P =0.032） while those for N staging was 91.7% and 83.3% （P =0.980）. Conclusions The sensitivity, specificity and accuracy of PET/CECT for differential diagnosis of benign and malignant pancreatic diseases are higher than those of PET/CT and it can more accurately evaluate vascular and organ invasion than that of PET/CT. Therefore, PET/CECT can be taken as a one-shop-stop imaging for diagnosis and preoperative assessment for patients with pancreatic diseases.