Expert radiologist Frank Gaillard discusses the evolving definitions and classifications of IDH-wildtype glioblastomas, highlighting the importance of molecular parameters in diagnosis. The podcast explores the challenges in imaging differentiation, advancements in MRI techniques for treatment monitoring, and post-operative follow-up protocols. Banter about supporting Radiopaedia and humorous lunch/dinner discussions add a light touch to the informative episode.
IDH mutation status is crucial in differentiating glioblastomas from lower-grade tumors and impacts prognosis.
MRI and PET scans play vital roles in accurately diagnosing and prognosing glioblastomas.
Maximal safe resection post-surgery is essential for glioblastoma treatment; new therapies like immunotherapy show promise.
Deep dives
Glioblastoma Tumors: Main Features and Classification
Glioblastoma (GBM) tumors are the most prevalent primary adult brain tumors, known for their aggressiveness and resistance to therapy. They often present as masses in the white matter with peripheral enhancement, necrosis, and vasogenic edema. Recent classifications emphasize IDH mutation status as a defining feature separating GBM from lower-grade astrocytomas.
Primary and Secondary Glioblastomas: Evolution and IDH Status
Primary glioblastomas develop denovo, while secondary ones arise from lower-grade tumors, correlating closely with IDH mutation status. The distinction between IDH wild type GBMs and IDH mutant astrocytomas is crucial in determining the tumor type and prognosis, with significant implications for treatment strategies.
Radiographic Features and Diagnostic Tools in Glioblastoma: MRI and PET Findings
MRI plays a pivotal role in identifying glioblastomas, showcasing features like central necrosis, irregular enhancement, and infiltrative behavior. PET scans reveal elevated FDG uptake, reflecting increased glucose metabolism. These imaging modalities, along with radiogenomics and molecular markers like MGMT methylation status, aid in accurate diagnosis and prognosis assessment of glioblastoma.
Key Points in Surgical Planning for Glioblastoma
When planning surgery for glioblastoma, understanding the involvement of eloquent areas, white matter tracks, and extension into the brainstem is crucial. Surgeons need to consider eloquent cortex involvement, the need for DTI imaging, and the presence of CSF dissemination or sub-apendimal spread. Focusing on areas beyond enhancing components post-surgery is essential to prevent under-treatment of non-enhancing tumor regions, which could lead to future radiotherapy challenges.
Treatment Approaches and Differential Diagnosis
After surgery, maximal safe resection remains vital for glioblastoma treatment, with advancements like supermaximal resection showing promise. Adjuvant chemo-radiotherapy with temozolomide is a common treatment protocol, while newer therapies like anti-angiogenesis and immunotherapy are emerging. Differential diagnoses, including astrocytoma, cerebral metastasis, and primary CNS lymphoma, require careful consideration due to overlapping imaging features and treatment implications.
Radiology read to you! Andrew reads the Radiopaedia article on glioblastoma to Frank. Definitions have changed in this area over the last decade with IDH-wildtype molecular status now forming the basis of diagnosis. Change can often cause confusion, but hopefully this episode helps keep everyone up to date and on the same page… for now at least.
