^(18)F-FDG PET/CT对肾上腺肿瘤的诊断价值

F-FDG PET/CT in the diagnosis of adrenal tumors

目的总结肾上腺肿瘤在^(18)F-FDG PET/CT显像上的特征,探讨^(18)F-FDG PET/CT对不同类型肾上腺肿瘤的诊断及鉴别诊断价值。方法134例肾上腺肿瘤,其中肾上腺髓质脂肪瘤6例,肾上腺皮质腺瘤17例,肾上腺皮质癌4例,肾上腺恶性嗜铬细胞瘤3例,肾上腺神经母细胞瘤9例,肾上腺淋巴瘤34例,肾上腺转移瘤61例;单侧肾上腺肿瘤93例,双侧肾上腺肿瘤41例;患者均行^(18)F-FDG PET/CT扫描,分析并比较不同类型肾上腺肿瘤的大小、形态、密度、肿瘤FDG摄取情况及最大标准摄取值(maximum standardized uptake value,SUV_(max));绘制ROC曲线,评估肿瘤SUV_(max)对良恶性肾上腺肿瘤的诊断效能。结果肾上腺髓质脂肪瘤的CT表现为低密度影,FDG摄取未见明显增高;肾上腺皮脂腺瘤表现为低密度影,FDG摄取未见明显增高或稍增高;肾上腺皮质癌表现为较大的软组织肿块伴坏死或钙化,FDG摄取异常增高;肾上腺恶性嗜铬细胞瘤表现为体积较大的不规则软组织肿块,FDG摄取不均匀性明显增高;肾上腺神经母细胞瘤表现为不规则软组织肿块伴斑点状或不规则形钙化,FDG摄取呈不均匀性增高,坏死区代谢减低;肾上腺淋巴瘤表现为形态规则、密度均匀、FDG摄取均匀性增高的软组织结节或肿块;肾上腺转移瘤形态规则或不规则,但密度均匀,FDG摄取均匀性不同程度增高;不同肾上腺肿瘤的大小、形态、密度、代谢特点及肿瘤SUV_(max)比较差异均有统计学意义(P<0.05)。当SUV_(max)最佳截断值为4.85时,诊断良恶性肾上腺肿瘤的AUC为0.951(95%CI:0.915~0.986,P<0.001),灵敏度为88.5%,特异度为88.9%。结论不同类型肾上腺肿瘤在^(18)F-FDG PET/CT表现上具有一定特性,该显像特征对鉴别肾上腺良恶性肿瘤有较高价值。

Objective To summarize the characteristics of adrenal tumors on ^(18)F-FDG PET/CT imaging, and to discuss the diagnosis and differential diagnosis of adrenal tumors by ^(18)F-FDG PET/CT. Methods Totally 134 patients with adrenal tumors(93 unilateral and 41 bilateral) included adrenal medullary lipoma in 6 patients, adrenal cortical adenoma in 17, adrenal cortical carcinoma in 4, malignant adrenal pheochromocytoma in 3, adrenal neuroblastoma in 9, lymphomas in 34, and adrenal metastastic tumor in 61. All patients underwent ^(18)F-FDG PET/CT scan to analyze and compare the size, shape, density, FDG uptake and maximum standardized uptake value(SUV_(max)) of different types of adrenal tumors. ROC curve was drawn to evaluate the efficiencies of the SUV_(max) on benign and malignant adrenal tumors. Results CT showed medullary lipoma in low-density shadows, and FDG uptake showed no obvious increase. CT showed sebaceous adenomas in low-density shadows, and FDG uptake showed no or slight increase. Adrenocortical carcinomas were manifested on CT as large soft tissue masses with necrosis or calcification, and FDG uptake showed an abnormal increase. Malignant pheochromocytoma was manifested as a large irregular soft tissue mass on CT, and FDG uptake showed a significant increase. Neuroblastoma was manifested as an irregular soft tissue mass with spot or irregular calcification on CT, and FDG uptake showed an uneven increase and decreased metabolism in the necrotic area. Lymphoma appeared regular morphology and uniform density, and FDG uptake showed evenly increased soft tissue nodules or masses. Adrenalmetastastic tumor was regular or irregular in morphology,but its density was uniform,and FDG uptake showed increased uniformity in different degrees.The size,shape,density,metabolic features and tumor SUV_(max) of different adrenal tumors were significantly different among different adrenal tumors(P<0.05).When the optimal cut-off value of SUV_(max) was 4.85,the AUCfor diagnosing benign and malignant adrenal tumors was 0.951(95%CI:0.915-0.986,P<0.001),the sensitivity was 88.5%,and the specificity was 88.9%.Conclusion Different types of adrenal tumors have certain characteristics on ^(18)F-FDG PET/CT,which has a high value to the differential diagnosis of benign and malignant adrenal tumors.