T 1 ρ $$ {}_{1\rho } $$ as a Biomarker for IDH1 Mutation Status in a Glioma Mouse Model

Area of Science:

• Neuroimaging
• Oncology
• Biomarkers

Background:

• Glioma treatment depends on IDH gene mutation status, but current diagnostic methods require invasive biopsies with long wait times.
• T1ρ (spin-lattice relaxation in the rotating frame) shows potential for faster, non-invasive IDH1-typing at clinical field strengths.
• Limited studies have explored the utility of T1ρ for IDH1-typing in gliomas.

Purpose of the Study:

• To investigate the potential of T1ρ MRI as a non-invasive method for differentiating IDH1-mutant from IDH1-wild-type gliomas.
• To assess the sensitivity of T1ρ to whole-brain changes associated with glioma and IDH status.

Main Methods:

• Three groups of five mice were used: naïve controls, IDH1-wild-type glioma-bearing, and IDH1-mutant glioma-bearing.
• Mice were imaged weekly using a T1ρ-prepped EPI sequence.
• Tumor T1ρ values were normalized to brain T1ρ values (ΔT1ρ) for comparison.

Main Results:

• IDH1-mutant gliomas exhibited significantly higher T1ρ values compared to the brain.
• IDH1-wild-type gliomas showed similar T1ρ values in the tumor and brain.
• A mean ΔT1ρ of ~29% distinguished IDH1-mutant gliomas, while IDH1-wild-type gliomas showed an average ΔT1ρ of ~3%.

Conclusions:

• Normalized T1ρ measurements (ΔT1ρ) can effectively distinguish between IDH1-mutant and IDH1-wild-type gliomas.
• T1ρ shows promise as a non-invasive biomarker for IDH1 typing in gliomas.
• Further research is needed to address confounding effects of T1 and T2 differences.