Characterizing the Diffusion Properties of Prostate Tissue Using Paired MR Microscopy and Multidimensional Diffusion...

Area of Science:

• Biomedical Imaging
• Diffusion MRI Physics
• Prostate Cancer Research

Background:

• Understanding diffusion properties of prostate tissues is crucial for cancer detection and characterization.
• Multidimensional diffusion MRI (dMRI) offers high-resolution insights into tissue microstructure.

Purpose of the Study:

• To characterize and compare diffusion properties of prostate epithelium and stroma in benign and cancerous tissues using advanced dMRI techniques.
• To evaluate the efficacy of different diffusion models in describing these tissue types.

Main Methods:

• Paired MR microscopy and multidimensional dMRI were performed on fixed prostate tissue samples at ultra-high field (16.4 T).
• Image segmentation identified epithelial, stromal, and luminal components.
• A linear signal model estimated aggregate epithelial and stromal signal contributions, followed by fitting four diffusion models.
• Model quality was assessed using the Akaike Information Criterion (AICc), with voxel-wise fitting for cancer comparison.

Main Results:

• The Ball+Sphere diffusion model provided the best fit for both epithelial and stromal tissues, outperforming the ADC model.
• Epithelium exhibited a higher sphere fraction and lower ball-compartment diffusivity compared to stroma.
• Gleason 3+3 cancer showed diffusion parameters similar to benign tissues, whereas Gleason 4+4 cancer displayed a significantly increased sphere fraction in epithelial components.

Conclusions:

• The Ball+Sphere model accurately describes direction-averaged diffusion in fixed prostate epithelium and stroma.
• Diffusion properties of epithelium in Gleason 3+3 prostate cancer are comparable to benign tissue.
• Gleason 4+4 prostate cancer demonstrates a notable increase in restricted water volume fraction within the epithelium.