Service de radiodiagnostic et radiologie interventionnelle, bureau CIBM 09-084, rue Bugnon 46, 1011 Lausanne, Switzerland.
Imaging department, Gustave-Roussy Cancer Campus, 114, rue Édouard-Vaillant, 94805 Villejuif cedex, France.
Diagn Interv Imaging. 2016 Dec;97(12):1241-1257. doi: 10.1016/j.diii.2016.07.012. Epub 2016 Nov 18.
Pancreatic neuroendocrine tumors (PNETs) are rare and represent a heterogeneous disease. PNET can be functioning or non-functioning with different clinical presentations and different prognosis based on WHO and pTNM classifications. The role of imaging includes the localization of small functioning tumor, differentiation of these tumors from adenocarcinoma, identification of signs of malignancy and evaluation of extent. PNETs have a broad spectrum of appearance. On CT and MRI, most of functioning PNETs are well defined small tumors with intense and homogeneous enhancement on arterial and portal phases. However, some PNETs with a more fibrous content may have a more delayed enhancement that is best depicted on the delayed phase. Other PNETs can present as purely cystic, complex cystic and solid tumors and calcified tumors. Non-functioning PNETs are larger with less intense and more heterogeneous enhancement. Functional imaging is useful for disease staging, to detect disease recurrence or the primary but also to select patient candidate for peptide receptor radiometabolic treatment. Somatostatin receptor scintigraphy (SRS) (Octreoscan) is still the most available technique. Gallium 68-SST analogue PET have been demonstrated to be more sensitive than SRS-SPEC and it will be the future of functional imaging for NET. Finally, FDG PET/CT is indicated for more aggressive PNET as defined either by negative SRS and huge tumor burden or ki67 above 10% or poorly differentiated PNEC tumors.
胰腺神经内分泌肿瘤（PNETs）较为罕见，属于异质性疾病。根据世界卫生组织（WHO）和 pTNM 分类，PNET 可以表现为功能性或无功能性，具有不同的临床表现和不同的预后。影像学的作用包括定位小的功能性肿瘤，将这些肿瘤与腺癌区分开来，识别恶性征象并评估肿瘤的范围。PNET 的表现多样。在 CT 和 MRI 上，大多数功能性 PNET 是界限清楚的小肿瘤，在动脉期和门静脉期有强烈且均匀的强化。然而，一些富含纤维的 PNET 可能会出现延迟强化，最佳的评估时间是延迟期。其他 PNET 可表现为单纯囊性、复杂囊性和实性肿瘤，以及钙化肿瘤。无功能性 PNET 较大，强化程度较低且不均匀。功能成像有助于疾病分期，以发现疾病复发或原发灶，也有助于选择肽受体放射性代谢治疗的候选患者。生长抑素受体闪烁显像（SRS）（奥曲肽扫描）仍然是最常用的技术。已证明镓 68-SST 类似物 PET 比 SRS-SPEC 更敏感，它将成为 NET 功能成像的未来。最后，FDG PET/CT 适用于侵袭性较强的 PNET，这些肿瘤的定义为 SRS 阴性和巨大肿瘤负荷，或 ki67 超过 10%，或分化较差的神经内分泌癌（PNEC）肿瘤。
