2021年世界卫生组织（WHO）对中枢神经系统（CNS）肿瘤的分类优先考虑异柠檬酸脱氢酶（IDH）突变以确定弥漫性胶质瘤的肿瘤类型，与2016年的分类方法相比，该方法更重视组织学特征。我们的目标是研究这一改变对质子磁共振波谱（1H-MRS）在区分高级别弥漫性星形细胞瘤亚组的表现的影响。回顾性检索具有CNS WHO级别3和4的弥漫性星形细胞瘤、已知IDH突变状态以及可用的1H-MRS的患者，并根据IDH突变状态和组织学分级将其分为4组。使用Kruskal-Wallis检验分析不同组之间的1H-MRS差异。选择显示最大差异的谱上的点来评估1H-MRS在区分3级和4级肿瘤（WHO 2016定义）以及IDH突变和IDH野生型肿瘤（WHO 2021）方面的表现。使用这些点构建ROC曲线，并计算和比较AUC值。该研究纳入了223例高级别的弥漫性星形细胞瘤患者。IDH突变和IDH野生型肿瘤之间的区分表现出更高的AUC值（最高AUC短TE，0.943；长TE，0.864）和更明显的视觉差异，而3级和4级肿瘤之间的区分表现出较低的AUC值（短TE，0.885；长TE，0.838）。我们的研究结果表明，基于2021年的分类标准，1H-MRS更适用于对高级别星形细胞瘤进行分类。通过新的分类标准，1H-MRS具有更好的代谢组学稳定性和更均匀的分组，从而更好地区分肿瘤类型。2021年世界卫生组织脑肿瘤分类将分子标准用于改进肿瘤表征。这导致磁共振波谱更好地区分了高级别弥漫性星形细胞瘤亚组，并需要进一步发展具有光谱学的脑肿瘤分类工具。• 新的2021年世界卫生组织更新的中枢神经系统肿瘤分类最大化了分子诊断在脑肿瘤分类中的作用。• 当使用新分类标准定义时，质子磁共振波谱在区分高级别星形细胞瘤亚组方面表现更好。• 该研究提供了使用新标准改善脑肿瘤亚组代谢表征的额外证据。©2023.作者（授权给欧洲放射学会）。

The 2021 World Health Organization (WHO) classification of central nervous system (CNS) tumors prioritizes isocitrate dehydrogenase (IDH) mutation to define tumor types in diffuse gliomas, in contrast to the 2016 classification, which prioritized histological features. Our objective was to investigate the influence of this change in the performance of proton MR spectroscopy (1H-MRS) in segregating high-grade diffuse astrocytoma subgroups.Patients with CNS WHO grade 3 and 4 diffuse astrocytoma, known IDH mutation status, and available 1H-MRS were retrospectively retrieved and divided into 4 groups based on IDH mutation status and histological grade. Differences in 1H-MRS between groups were analyzed with the Kruskal-Wallis test. The points on the spectrum that showed the greatest differences were chosen to evaluate the performance of 1H-MRS in discriminating between grades 3 and 4 tumors (WHO 2016 defined), and between IDH-mutant and IDH-wildtype tumors (WHO 2021). ROC curves were constructed with these points, and AUC values were calculated and compared.The study included 223 patients with high-grade diffuse astrocytoma. Discrimination between IDH-mutant and IDH-wildtype tumors showed higher AUC values (highest AUC short TE, 0.943; long TE, 0.864) and more noticeable visual differences than the discrimination between grade 3 and 4 tumors (short TE, 0.885; long TE, 0.838).Our findings suggest that 1H-MRS is more applicable to classify high-grade astrocytomas defined with the 2021 criteria. Improved metabolomic robustness and more homogeneous groups yielded better tumor type discrimination by 1H-MRS with the new criteria.The 2021 World Health Organization classification of brain tumors empowers molecular criteria to improve tumor characterization. This derives in greater segregation of high-grade diffuse astrocytoma subgroups by MR spectroscopy and warrants further development of brain tumor classification tools with spectroscopy.• The new 2021 updated World Health Organization classification of central nervous system tumors maximizes the role of molecular diagnosis in the classification of brain tumors. • Proton MR spectroscopy performs better to segregate high-grade astrocytoma subgroups when defined with the new criteria. • The study provides additional evidence of improved metabolic characterization of brain tumor subgroups with the new criteria.© 2023. The Author(s), under exclusive licence to European Society of Radiology.