Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine, Medical University of Vienna, Vienna General Hospital, Waehringer Guertel 18-20, 1090 Vienna, Austria.
Anticancer Res. 2014 Feb;34(2):791-5.
To describe the (18)F-fluorodihydro-xyphenylalanine ((18)F-DOPA), positron emission tomography (PET) and magnetic resonance imaging (MRI) appearance of pheochromocytomas, with a focus on the presence or absence of typical MRI features.
Eleven patients with histologically-verified pheochromocytoma [sporadic (n=9), multiple endocrine neoplasia (MEN) 2A syndrome (n=2)] were enrolled retrospectively. All patients underwent an MRI examination of the upper abdomen. Nine out of 11 patients underwent (18)F-DOPA PET/CT, and the remaining two patients underwent independent PET and computed tomography (CT) examinations. (18)F-DOPA-PET/CT examinations were considered positive when an increased tracer accumulation in the adrenal region, as shown on CT images, was observed. When an adrenal mass was detected on MRI, the T1 and T2 signal intensity and contrast enhancement pattern were recorded. Based on MR characteristics, the lesions were divided into typical and atypical.
Ten out of 11 patients had one lesion, while one patient had two lesions. All pheochromocytomas were detected by both PET/CT and MRI. On (18)F-DOPA scans, all lesions showed an increased tracer accumulation, with a mean maximum standardized uptake value (SUVmax) of 13.7±5.75. Eight out of 12 pheochromocytomas exhibited typical MRI features, with intermediate signal intensity on T1-weighted images in-phase, absence of signal drop on T1-weighted images out-of-phase, high signal intensity on T2-weighted images, and clear contrast enhancement in the arterial phase. The remaining four lesions exhibited atypical MRI features, namely absence of one of the listed criteria.
In the assessment of pheochromocytoma, the combination of (18)F-DOPA PET with MRI is superior to MRI-alone. (18)F-DOPA PET/MRI may yield a higher diagnostic confidence for the detection of pheochromocytoma than (18)F-DOPA PET/CT.
描述（18）F-氟代二羟苯丙氨酸（（18）F-DOPA）、正电子发射断层扫描（PET）和磁共振成像（MRI）在嗜铬细胞瘤中的表现，重点关注是否存在典型的 MRI 特征。
回顾性纳入 11 例经组织学证实的嗜铬细胞瘤患者[散发性（n=9）、多发性内分泌肿瘤 2A 综合征（MEN 2A）（n=2）]。所有患者均行上腹部 MRI 检查。11 例患者中有 9 例行（18）F-DOPA PET/CT 检查，其余 2 例行独立 PET 和计算机断层扫描（CT）检查。当 CT 图像上观察到肾上腺区域的示踪剂积聚增加时，（18）F-DOPA-PET/CT 检查被认为是阳性的。当 MRI 检测到肾上腺肿块时，记录 T1 和 T2 信号强度和对比增强模式。根据 MRI 特征，将病变分为典型和非典型。
11 例患者中有 10 例发现 1 个病灶，1 例发现 2 个病灶。所有嗜铬细胞瘤均通过 PET/CT 和 MRI 检测到。在（18）F-DOPA 扫描中，所有病灶均显示示踪剂积聚增加，最大标准化摄取值（SUVmax）平均为 13.7±5.75。12 个嗜铬细胞瘤中有 8 个显示典型 MRI 特征，同相位 T1 加权图像上呈中等信号强度，反相位 T1 加权图像上信号无下降，T2 加权图像上呈高信号强度，动脉期对比增强清晰。其余 4 个病灶表现出非典型 MRI 特征，即缺少上述标准之一。
在评估嗜铬细胞瘤时，（18）F-DOPA PET 与 MRI 的结合优于单独使用 MRI。（18）F-DOPA PET/MRI 对嗜铬细胞瘤的检测可能比（18）F-DOPA PET/CT 具有更高的诊断信心。
