Moreau Aurélie, Giraudet Anne L, Kryza David, Borson-Chazot Françoise, Bournaud Claire, Mognetti Thomas, Lifante Jean-Christophe, Combemale Patrick, Giammarile Francesco, Houzard Claire
Departments of aNuclear Medicine bEndocrinology, GHE cEndocrine Surgery, GHS, CHU Lyon dDepartment of Nuclear Medicine eDermatology Unit, CLB Lyon fEA 3637, Lyon 1 University, Lyon, France gDepartment of Nuclear Sciences and Applications, Vienna International Centre, Division of Human Health, Nuclear Medicine and Diagnostic Imaging Section, International Atomic Energy Agency, Vienna, Austria.
Nucl Med Commun. 2017 Sep;38(9):771-779. doi: 10.1097/MNM.0000000000000708.
Many studies have reported the high performance of 6-fluorine-18-fluorodihydroxyphenilalanine (F-FDOPA) PET/CT in the diagnosis of pheochromocytomas but nobody seems to have investigated physiological and pathological adrenal glands from a quantitative point of view. The purpose of the present study was to assess the quantitative F-FDOPA uptake of normal and pathologic adrenal glands and to establish thresholds to characterize pheochromocytomas. We were especially interested in characterizing the remaining adrenal glands captation after an adrenalectomy.
We reviewed 112 F-FDOPA PET/CT scans taken for different indications. A total of 212 adrenal glands, of which 17 were pheochromocytomas, were analyzed on the basis of their functional and morphological features. The final diagnosis was based on histologic proof when available (six pheochromocytomas) or after synthesis of clinical, biological, morphological, and functional results. Maximum standardized uptake value (SUVmax), mediastinum, and liver ratios in case of pheochromocytomas, adenomas, and solitary adrenal glands were determined and compared with those of healthy glands. Receiver operating characteristic curves were determined and areas under the curve were compared for different cutoffs of each index.
Pheochromocytomas demonstrated a higher F-FDOPA uptake compared with normal adrenal glands (mean SUVmax: 7.5, SD 4.0, range: 3.5-20.0 vs. mean SUVmax: 2.6, SD: 0.8, range: 1.0-6.9) (P<0.0001). An SUVmax threshold of 4.2 has a sensitivity and specificity of 94 and 98%, respectively. The areas under the curve were 0.988, 0.991, and 0.987 for an SUVmax of 4.2, a mediastinum ratio of 3.0, and a liver ratio of 1.7, respectively. A large number of nonsecreting pheochromocytomas were noticed. On the basis of the SUVmax no statistically significant difference was found between secreting (SUVmax: 8.9, SD: 5.3) and nonsecreting pheochromocytomas (SUVmax: 5.1, SD: 0.9) (P=0.141). After unilateral adrenalectomy, solitary glands presented no increased uptake compared with healthy adrenal glands. An unexpected lower captation was also observed (SUVmax: 2.0, P=0.047).
We confirm the high affinity of F-FDOPA for secreting or nonsecreting pheochromocytoma. Indeed within a series of various adrenal glands, only these tumors presented a significant increased uptake compared with normal adrenal glands. Because of a high rate of nonhypersecreting lesions, F-FDOPA can act as a surrogate to biological assays. After an adrenalectomy, the remaining glands did not demonstrate compensatory accumulation of F-FDOPA. To our knowledge this last point has never been addressed.
许多研究报告了6-氟-18-氟二羟基苯丙氨酸（F-FDOPA）PET/CT在嗜铬细胞瘤诊断中的高性能，但似乎没有人从定量角度研究生理和病理状态下的肾上腺。本研究的目的是评估正常和病理肾上腺的F-FDOPA摄取量，并确定用于表征嗜铬细胞瘤的阈值。我们特别感兴趣的是表征肾上腺切除术后剩余肾上腺的摄取情况。
我们回顾了112例因不同适应证进行的F-FDOPA PET/CT扫描。根据其功能和形态特征分析了总共212个肾上腺，其中17个为嗜铬细胞瘤。最终诊断在有组织学证据时（6例嗜铬细胞瘤）基于组织学证据，或在综合临床、生物学、形态学和功能结果后做出。测定了嗜铬细胞瘤、腺瘤和孤立肾上腺的最大标准化摄取值（SUVmax）、纵隔和肝脏比值，并与健康肾上腺的进行比较。确定了受试者操作特征曲线，并比较了每个指标不同截断值下的曲线下面积。
与正常肾上腺相比，嗜铬细胞瘤表现出更高的F-FDOPA摄取（平均SUVmax：7.5，标准差4.0，范围：3.5 - 20.0，而平均SUVmax：2.6，标准差：0.8，范围：1.0 - 6.9）（P<0.0001）。SUVmax阈值为4.2时，敏感性和特异性分别为94%和98%。SUVmax为4.2、纵隔比值为3.0和肝脏比值为1.7时的曲线下面积分别为0.988、0.991和0.987。发现了大量无分泌功能的嗜铬细胞瘤。基于SUVmax，分泌性（SUVmax：8.9，标准差：5.）和无分泌功能的嗜铬细胞瘤（SUVmax：5.1，标准差：0.9）之间未发现统计学显著差异（P = 0.141）。单侧肾上腺切除术后，孤立肾上腺与健康肾上腺相比摄取未增加。还观察到意外的较低摄取（SUVmax：2.0，P = 0.047）。
我们证实了F-FDOPA对分泌性或无分泌功能嗜铬细胞瘤具有高亲和力。事实上，在一系列不同的肾上腺中，只有这些肿瘤与正常肾上腺相比表现出显著增加的摄取。由于无高分泌性病变的发生率较高，F-FDOPA可作为生物学检测的替代方法。肾上腺切除术后，剩余肾上腺未显示F-FDOPA的代偿性蓄积。据我们所知，最后这一点从未被提及过。
