Department of Neurosurgery, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.
Clin Nucl Med. 2019 Apr;44(4):265-271. doi: 10.1097/RLU.0000000000002460.
This study aimed to determine the most effective metabolic index of FDG-PET and MET-PET to differentiate high- and low-grade gliomas, and then to characterize tumor metabolism according to the 2016 WHO classification. We also developed a new calculation method of potential infiltrative tumor volume to overcome the current limitations of tumor evaluation according to metabolic index, which focuses solely on tumor core area.
Patients who underwent both FDG-PET and MET-PET, as well as surgical treatment, were retrospectively identified. All tumors were diagnosed histologically and included 44 high-grade and 19 low-grade gliomas. Metabolic indices of tumor-to-normal (T/N) ratio and maximum value within the tumor itself were compared between high- and low-grade tumors. A calculation method for potential infiltrative tumor volume was developed and compared between these 2 grades.
T/N, calculated as tumor value divided by normal cortex value, was the most effective (area under the curve, 0.800 for FDG-PET; area under the curve, 0.773 for MET-PET) for differentiating high- and low-grade gliomas. Potential infiltrative volume effectively distinguished between high- and low-grade glioma (43.8 ± 30.2 mL vs 14.0 ± 12.6 mL; P = 0.005 [t test]). A combination of T/N, with a cutoff value of 0.9 or higher on FDG-PET and/or 3.0 or higher on MET-PET, and potential infiltrative volume, with a cutoff value of 20.0 mL or higher, provided a diagnostic accuracy of 89% in distinguishing high- from low-grade gliomas.
Evaluation of potential infiltrative volume surrounding the tumor core area, in addition to the T/N ratio of the tumor core, may help distinguish between high- and low-grade gliomas.
本研究旨在确定 FDG-PET 和 MET-PET 中最有效的代谢指标，以区分高级别和低级别胶质瘤，并根据 2016 年 WHO 分类对肿瘤代谢进行特征描述。我们还开发了一种新的潜在浸润性肿瘤体积计算方法，以克服目前仅根据代谢指标（主要关注肿瘤核心区域）评估肿瘤的局限性。
回顾性分析了同时接受 FDG-PET 和 MET-PET 检查并接受手术治疗的患者。所有肿瘤均经组织学诊断，包括 44 例高级别和 19 例低级别胶质瘤。比较了高级别和低级别肿瘤之间肿瘤与正常组织的比值（T/N）和肿瘤内最大代谢值。开发了一种潜在浸润性肿瘤体积的计算方法，并对这两种分级进行了比较。
T/N（肿瘤值除以正常皮质值）是区分高级别和低级别胶质瘤最有效的代谢指标（FDG-PET 的曲线下面积为 0.800；MET-PET 的曲线下面积为 0.773）。潜在浸润性体积能够有效区分高级别和低级别胶质瘤（43.8±30.2 mL 比 14.0±12.6 mL；P=0.005 [t 检验]）。将 T/N（FDG-PET 的截断值≥0.9 或更高，MET-PET 的截断值≥3.0 或更高）与潜在浸润性体积（截断值≥20.0 mL）相结合，可在区分高级别和低级别胶质瘤方面提供 89%的诊断准确率。
评估肿瘤核心区域周围的潜在浸润性体积，加上肿瘤核心区域的 T/N 比值，可能有助于区分高级别和低级别胶质瘤。
