Comprehensive multicentre retrospective analysis for predicting isocitrate dehydrogenase-mutant lower-grade gliomas.

Objective: To differentiate glioma grading and determine isocitrate dehydrogenase (IDH) mutation status, which are crucial for prognosis assessment and treatment planning in glioma patients.

Methods: This retrospective study included patients diagnosed with adult diffuse glioma from 1 January, 2018 to 31 July, 2023 in two independent institutions. It documented and analysed clinical and radiographic features. A nomogram model was constructed using stepwise regression to predict lower-grade gliomas and IDH mutation status.

Results: A total of 383 adult patients with diffuse glioma were included in the study, with Cohort A (297 patients) serving as the training set and Cohort B (86 patients) serving as the validation cohort. Consistent with previous reports, the Hyper fluid-attenuated inversion recovery (FLAIR) rim sign exhibited higher sensitivity in lower-grade gliomas for IDH mutant gliomas compared with the T2-FLAIR mismatch sign. However, the Hyper FLAIR rim sign was also present in Grade 4 gliomas, and thus, the T2-FLAIR mismatch sign exhibited better clinical efficacy in predicting glioma grade and IDH mutation compared with the Hyper FLAIR rim sign in clinical applications. Meanwhile, preoperative magnetic resonance spectroscopy (MRS) indicators, particularly the Cho/Cr ratio, have shown excellent performance in predicting glioma grade and IDH mutation status. The nomogram developed through stepwise regression demonstrated excellent predictive capabilities in distinguishing glioma grade and IDH mutation status.

Interpretation: Combining imaging and molecular features, the predictive model established in this study offers a reliable non-invasive tool for predicting glioma grading and IDH mutation status, aiding the clinical decision-making process and improving patient management.