GliomaAI-Astro23: MRI-Based Detection of IDH Mutant Astrocytoma (Grade 2 and 3)

The goal of this observational study is to learn whether an artificial intelligence system called GliomaAI-Astro23 can help detect a specific molecular type of brain tumour called IDH mutant Astrocytoma (grade 2 and 3) using routine MRI scans. The study uses previously collected and fully anonymised MRI data from 1,372 patients from 13 institutions in the Cancer Imaging Archive (TCIA). The main questions it aims to answer are: * How accurately can GliomaAI-Astro23 identify IDH mutant Astrocytoma (grade 2 and 3) from MRI scans? * How well does the system perform across data from different hospitals and patient groups? Researchers will use existing MRI scans and clinical information to train and test the AI system. No new scans, treatments, or hospital visits are required for participants, and all data used is fully anonymised and obtained from an existing research database. Participants will not be asked to do anything, as this study only uses previously collected imaging data.

Inclusion Criteria: * Adult (\>=18 years of age) * Having pre op MRI scan * Having biopsy / surgery * Having post biopsy/ surgery histology diagnosis and genetic analysis. Exclusion Criteria: * MRI scan significantly degraded by motion or other artefact * Incomplete genetic analysis * Prior treatment (e.g., radiotherapy or chemotherapy) before baseline MRI