The impeded diffusion fraction quantitative imaging assay demonstrated in multi-exponential diffusion phantom and...

Area of Science:

• Biomedical Imaging
• Diffusion MRI Physics
• Quantitative Biomarkers

Background:

• Diffusion-weighted imaging (DWI) is crucial for cancer detection.
• Quantifying water diffusion in complex biological tissues remains challenging.
• Existing models struggle to differentiate tissue microenvironments effectively.

Purpose of the Study:

• To introduce and validate a novel method for quantifying impeded diffusion fraction (IDF).
• To assess IDF's utility in cancer grading using conventional clinical DWI protocols.
• To compare IDF performance against established diffusion MRI metrics.

Main Methods:

• Developed the IDF formalism to model water diffusion in distinct cellular compartments.
• Validated IDF using diffusion phantoms with varying compartment sizes and macromolecule concentrations.
• Applied IDF to in vivo prostate cancer (PCa) cases, correlating results with histopathology.

Main Results:

• IDF demonstrated linear scaling with compartment size and macromolecule concentration in phantoms.
• IDF values increased with PCa histopathologic grade (Gleason score).
• IDF showed superior performance in distinguishing low-grade PCa, reducing false positives compared to ADC.

Conclusions:

• The proposed IDF method provides accurate, quantitative imaging assays for cancer grading.
• IDF is robust across different b-value sets, including standard clinical protocols.
• This technique holds potential for improving diagnostic accuracy in oncology using routine DWI.