Department of Nuclear Medicine, University Hospital Essen, University of Duisburg-Essen.
Institute of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, University Duisburg-Essen.
Nucl Med Commun. 2020 Apr;41(4):363-369. doi: 10.1097/MNM.0000000000001150.
Neuroendocrine tumors (NETs) are known to overexpress somatostatin receptors (SSTR), which can be visualized by DOTATOC-PET. Reduced SSTR expression on the other hand may indicate dedifferentiation. The aim of this retrospective study was to assess, if conventional PET parameters and textural features (TF) derived from simultaneous PET and MRI including apparent diffusion coefficient (ADC) are associated with the proliferative activity of NETs, potentially allowing non-invasive tumor grading.
Our institutional database was screened for patients with NET and liver metastases >1 cm. We assessed conventional PET parameters, such as maximum and mean standardized uptake value and more elaborate TF parameters from PET and ADC-MRI (including entropy and homogeneity) from up to the five largest liver lesions per patient. The association of proliferative activity as measured by Ki67-/MIB1-index with the aforementioned parameters was analyzed.
One hundred patients with NET/NECs were eligible with a Ki67-index ranging from <1% to 30%. Overall, 304 liver lesions were analyzed. Conventional PET parameters, entropy, homogeneity of PET and ADC maps differed significantly between G1 and G2 NETs. However, Spearman's test showed a weak association (r = -0.23 to 0.31).
In our study cohort, conventional PET parameters and TF of PET and ADC-MRI showed only a weak correlation with Ki67. This indicates that in patients with a Ki67-index of up to 30% TF analysis of combined PET/MRI may not be reliably used for accurate non-invasive tumor grading. On the other hand, DOTATOC-PET might be a suitable staging tool in some higher grade NET/NECs.
神经内分泌肿瘤（NET）已知过度表达生长抑素受体（SSTR），可通过 DOTATOC-PET 进行可视化。另一方面，SSTR 表达减少可能表明去分化。本回顾性研究旨在评估常规 PET 参数和源自同时 PET 和 MRI 的纹理特征（TF）（包括表观扩散系数 [ADC]）是否与 NET 的增殖活性相关，从而潜在地实现非侵入性肿瘤分级。
我们的机构数据库筛选出 NET 和肝转移灶>1cm 的患者。我们评估了常规 PET 参数，如最大和平均标准化摄取值，以及来自每位患者最多 5 个最大肝病变的 PET 和 ADC-MRI 的更精细 TF 参数（包括熵和同质性）。分析增殖活性（如 Ki67-/MIB1-指数）与上述参数的相关性。
100 名 NET/NEC 患者符合条件，Ki67 指数范围为<1%至 30%。总体上，分析了 304 个肝病变。常规 PET 参数、熵、PET 和 ADC 图的同质性在 G1 和 G2 NET 之间存在显著差异。然而，Spearman 检验显示出较弱的相关性（r=-0.23 至 0.31）。
在我们的研究队列中，常规 PET 参数和 PET 和 ADC-MRI 的 TF 与 Ki67 仅显示出较弱的相关性。这表明在 Ki67 指数高达 30%的患者中，TF 分析联合 PET/MRI 可能无法可靠地用于准确的非侵入性肿瘤分级。另一方面，DOTATOC-PET 可能是一些高级别 NET/NEC 的合适分期工具。
