A Study to Evaluate the Safety and Efficacy of Intracranial Venous Blood Sampling for Liquid Biopsy in the Diagnosis of Brain Cancers

To learn if drawing blood directly from veins inside the brain is safe and can effectively provide the same kind of detailed information about high-grade glioma as traditional surgical biopsy.

Primary Objectives The primary objective is to evaluate the safety and efficacy of intracranial venous sampling with or without BBB disruption with administration of intraarterial mannitol in participants with high grade gliomas. * The study will determine if intracranial venous blood sampling for liquid biopsy can facilitate accurate and precise molecular diagnosis in participants with high grade gliomas that is comparable to molecular diagnosis obtained during surgical brain biopsy. * The study will determine if intracranial venous blood sampling for liquid biopsy requires concomitant temporary blood brain barrier disruption with endovascular selective intraarterial infusion of mannitol for accurate and precise molecular diagnosis of high-grade gliomas. Secondary Objectives • The study will determine if intracranial venous blood sampling in participants with high grade gliomas results in higher yield of ctDNA and other biomarkers than peripheral venous blood sampling, and if this is further augmented by BBB disruption.