Multimodal radiomics using MRI and amino acid PET in neuro-oncology

代谢成像技术，如正电子发射断层扫描(PET)，可以表征胶质瘤特定的代谢和细胞特征，这可能提供结构磁共振成像(MRI)以外的临床相关信息。在过去的几年里，使用放射性标记氨基酸的PET已经成为一种重要的诊断工具，以克服传统MRI的一些缺点。放射组学的价值已经被评估在脑肿瘤患者的各种临床应用中，例如预测神经肿瘤治疗的反应或对重要分子标志物的非侵入性评估。目前，这些研究大多仅基于磁共振成像。相比之下，氨基酸PET放射组学研究仍然很少。然而，过去几年的几项研究表明，氨基酸PET放射组学提供了有价值的额外诊断信息。计划中的工作计划的第一个目标是开发和评估基于氨基酸PET/MRI和放射组学的脑肿瘤患者治疗反应的自动化和客观评估。目前，脑肿瘤患者的疗效评估主要基于人工对比剂增强MRI的评估。在临床具有挑战性的情况下，添加氨基酸PET似乎特别有帮助，例如评估无强化的病变，以及区分与治疗相关的变化和肿瘤进展。到目前为止，将放射组学整合到反应评估中的潜力还没有被研究过。因此，包括氨基酸PET/MRI和放射组学在内的全自动和客观的治疗反应评估将具有很高的临床意义。拟议的翻译研究项目的第二个目标是建立第一个开放的脑肿瘤患者氨基酸PET/MRI数据库。放射组学的性能得益于大量的成像数据、组织分子和临床信息。在神经肿瘤学中，可用的数据集数量很少，这使得开发健壮和可靠的诊断、预测和预后放射组学模型尤其具有挑战性。克服这一限制的一种常见方法是使用开放数据库，如癌症影像档案(TCIA)。到目前为止，还没有氨基酸PET的这样的库，特别是PET/MRI的杂交库。我们项目的第三个重点是将局部放射组学特征与潜在的肿瘤生物学联系起来。在这里，来自图像引导的立体定向系列活检的局部组织分子数据将与术前氨基酸PET/MRI数据和局部放射组学特征图在空间上联系起来。如果可以评估有意义的相关性，结果将提供对生物学意义的进一步洞察，并可能有助于放射组学的更广泛接受和成功的临床翻译。

Metabolic imaging techniques such as positron emission tomography (PET) characterize specific metabolic and cellular features of gliomas which may provide clinically relevant information beyond structural magnetic resonance imaging (MRI). In the last years, PET using radiolabeled amino acids has become an important diagnostic tool to overcome some of the shortcomings of conventional MRI. The value of radiomics has been assessed for various clinical applications in patients with brain tumors such as the prediction of response to neuro-oncological treatment or the noninvasive assessment of important molecular markers. At present, most of these studies are based on MRI alone. In contrast, amino acid PET radiomics studies remain scarce. Nevertheless, several studies in the last years demonstrated that amino acid PET radiomics provides valuable additional diagnostic information. The first goal of the planned work program is to develop and evaluate an automated and objective assessment of treatment response based on amino acid PET/MRI and radiomics in patients with brain tumors. Currently, response assessment in brain tumor patients is mainly based on the manual evaluation of contrast-enhanced MRI. The addition of amino acid PET seems especially helpful in clinically challenging situations such as the evaluation of non-enhancing lesions as well as the differentiation of treatment-related changes from tumor progression. So far, the potential of integrating radiomics into response assessment has not been investigated. Therefore, a fully automated and objective assessment of treatment response including amino acid PET/MRI and radiomics would be of high clinical relevance. The second goal of the proposed translational research project is to establish the first open database of amino acid PET/MRI of patients with brain tumors. The performance of radiomics benefits from large amounts of imaging data, histomolecular, and clinical information. In Neuro-Oncology, the number of available datasets is low, which makes the development of robust and reliable diagnostic, predictive and prognostic radiomics models especially challenging. A common way to overcome this limitation is to use open databases such as The Cancer Imaging Archive (TCIA). Up to now, such repository does not yet exist for amino acid PET, especially not for hybrid PET/MRI. The third focus of our project is to correlate local radiomics features with the underlying tumor biology. Here, local histomolecular data from image-guided stereotactic serial biopsies will be spatially linked with preoperative amino acid PET/MRI data and local radiomics feature maps. In case meaningful correlations can be assessed, the results would provide further insights into biological meaning and potentially aid towards a broader acceptance and a successful clinical translation of radiomics.