T2-FLAIR mismatch in isocitrate dehydrogenase mutant astrocytomas: Variability and evolution
Patrick Throckmorton1, Jerome J Graber2
1From the School of Medicine (P.T.) and Departments of Neurology and Neurosurgery at the Alvord Brain Tumor Center (J.J.G.), the University of Washington; and Seattle Cancer Care Alliance (J.J.G.), WA.
Neurology
|July 22, 2020
Summary
The T2-fluid-attenuated inversion recovery (FLAIR) mismatch sign (T2FM) reliably predicts IDH mutations in astrocytomas, even with varied T2 appearances. This imaging marker shows distinct radiographic changes and can aid in predicting tumor status.
Area of Science:
- Neuro-oncology
- Radiology
- Molecular Diagnostics
Background:
- The T2-fluid-attenuated inversion recovery (FLAIR) mismatch sign (T2FM) is an MRI-based marker used in astrocytoma diagnosis.
- Its predictive value, especially concerning T2 appearance variations and IDH mutation status, requires further characterization.
Observation:
- Astrocytoma cases (n=64) were analyzed for T2FM, tumor characteristics, and radiographic evolution.
- Tumors were categorized based on T2 appearance and FLAIR rim presence: classic, geographic, and negative.
- Comparison of groups utilized statistical analyses, including chi-squared tests.
Findings:
- Including geographic tumors enhanced T2FM sensitivity for astrocytomas without compromising IDH mutation specificity.
- T2FM-positive tumors were more cystic, less enhancing, affected younger patients, and showed distinct temporal changes.
- T2FM predicted IDH mutation status, particularly when antibody testing was negative, and was observed in high-grade gliomas.
Implications:
- A hyperintense FLAIR rim, irrespective of T2 appearance, is a robust predictor of IDH mutation in astrocytomas.
- T2FM's dynamic radiographic changes and association with tumor characteristics offer valuable insights for clinical management.
- This imaging sign can be integrated with other variables to improve the prediction of IDH mutation status in astrocytomas.
