Revealing tumor microstructure with oscillating diffusion encoding MRI in pre-surgical and post-treatment glioma
Ante Zhu1, Robert Shih2,3, Raymond Y Huang4
1GE Research, Niskayuna, New York, USA.
Purpose:
We hypothesized that the time-dependent diffusivity at short diffusion times, as measured by oscillating gradient spin echo (OGSE) diffusion MRI, can characterize tissue microstructures in glioma patients.
Theory And Methods:
Five adult patients with known diffuse glioma, including two pre-surgical and three with new enhancing lesions after treatment for high-grade glioma, were scanned in an ultra-high-performance gradient 3.0T MRI system. OGSE diffusion MRI at 30-100 Hz and pulsed gradient spin echo diffusion imaging (approximated as 0 Hz) were obtained. The ADC and trace-diffusion-weighted image at each acquired frequency were calculated, that is, ADC (f) and TraceDWI (f).
Results:
In pre-surgical patients, biopsy-confirmed solid enhancing tumor in a high-grade glioblastoma showed higher and lower , compared to that at same OGSE frequency in a low-grade astrocytoma. In post-treatment patients, the enhancing lesions of two patients who were diagnosed with tumor progression contained more voxels with high and low , compared to the enhancing lesions of a patient who was diagnosed with treatment effect. Non-enhancing T2 signal abnormality lesions in both the pre-surgical high-grade glioblastoma and post-treatment tumor progressions showed regions with high and low , consistent with infiltrative tumor. The solid tumor of the glioblastoma, the enhancing lesions of post-treatment tumor progressions, and the suspected infiltrative tumors showed high diffusion time-dependency from 30 to 100 Hz, consistent with high intra-tumoral volume fraction (cellular density).
Conclusion:
Different characteristics of OGSE-based time-dependent diffusivity can reveal heterogenous tissue microstructures that indicate cellular density in glioma patients.
Insights
Oscillating gradient spin echo (OGSE) diffusion MRI reveals tissue microstructure in glioma patients. Time-dependent diffusivity measurements characterize tumor heterogeneity and cellular density, aiding in diagnosis and treatment assessment.
Area of Science:
- Neuroimaging
- Biophysics
- Oncology
Background:
- Gliomas exhibit complex microstructural variations.
- Accurate characterization of tissue microstructure is crucial for glioma diagnosis and management.
- Current diffusion MRI techniques may not fully capture the heterogeneity of glioma microenvironments.
Purpose of the Study:
- To investigate the utility of time-dependent diffusivity, measured by oscillating gradient spin echo (OGSE) diffusion MRI, in characterizing tissue microstructures within glioma patients.
- To correlate OGSE-derived diffusivity metrics with cellular density and tumor characteristics.
Main Methods:
- Utilized ultra-high-performance gradient 3.0T MRI to acquire OGSE diffusion MRI data (30-100 Hz) and conventional pulsed gradient spin echo (0 Hz) in five adult glioma patients.
- Calculated apparent diffusion coefficient (ADC(f)) and trace-diffusion-weighted imaging (TraceDWI(f)) at various frequencies.
- Analyzed diffusion time-dependency in pre-surgical and post-treatment glioma lesions.
Main Results:
- High-grade glioblastoma showed higher ADC and lower TraceDWI compared to low-grade astrocytoma at equivalent OGSE frequencies.
- Post-treatment enhancing lesions indicating tumor progression exhibited higher ADC and lower TraceDWI than those attributed to treatment effect.
- Non-enhancing lesions and infiltrative tumor areas demonstrated high diffusion time-dependency, consistent with increased cellular density.
Conclusions:
- OGSE-based time-dependent diffusivity effectively differentiates tissue microstructures in glioma patients.
- These diffusivity characteristics correlate with cellular density and can distinguish between tumor types, progression, and treatment effects.
- OGSE diffusion MRI offers a promising approach for non-invasively assessing glioma heterogeneity.
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