Comparison of apparent diffusion coefficients and distributed diffusion coefficients in high-grade gliomas.

Area of Science:

• Radiology
• Medical Imaging
• Oncology

Background:

• High-grade gliomas are aggressive brain tumors.
• Diffusion-weighted MRI is crucial for characterizing tumor microenvironment.
• Apparent diffusion coefficients (ADCs) are commonly used but rely on simplified models.

Purpose of the Study:

• To compare apparent diffusion coefficients (ADCs) with distributed diffusion coefficients (DDCs) in high-grade gliomas.
• To evaluate the accuracy of different diffusion models in quantifying tumor diffusion.

Main Methods:

• Prospective diffusion-weighted MRI in 20 high-grade glioma patients.
• Creation of traditional ADC maps (b-values 0, 1000 s/mm²).
• Generation of DDC maps using the stretched-exponential model (b-values 0, 1000, 2000, 4000 s/mm²).

Main Results:

• Tumor ADCs were significantly lower than DDCs (P=0.0001).
• Strong correlation observed between ADCs and DDCs (R=0.9716, P<0.0001).
• Greater discordance between ADC and DDC noted at higher ADC values.

Conclusions:

• The stretched-exponential model may provide a more accurate diffusion estimate than the mono-exponential model.
• Mono-exponential ADC models perform well for low diffusion attenuation in gliomas.
• Mono-exponential ADC models show limitations with greater diffusion attenuation.