A biomimetic tumor tissue phantom for validating diffusion-weighted MRI measurements

Area of Science:

• Biomedical Engineering
• Medical Imaging
• Materials Science

Background:

• Developing accurate phantoms for diffusion-weighted (DW) MRI is crucial for understanding water diffusion in biological tissues, particularly in tumors.
• Existing phantoms often lack the microstructural complexity to fully replicate in vivo conditions, limiting the validation of DW-MRI measurements.

Purpose of the Study:

• To create a novel biomimetic tumor tissue phantom that better mimics water diffusion in biological tissues compared to previous phantoms.
• To assess the long-term stability of this biomimetic phantom.
• To evaluate its utility in validating diffusion-weighted MRI measurements.

Main Methods:

• Coaxial-electrospraying was employed to fabricate micron-sized hollow polymer spheres, simulating cellular structures.
• The bulk phantom structure was submerged in water and its apparent diffusion coefficient (ADC) and microstructural properties were analyzed over 10 months.
• Scanning electron microscopy (SEM) and high-resolution synchrotron-CT were used for independent microstructural characterization and to assess repeatability.

Main Results:

• The biomimetic phantom demonstrated stable apparent diffusion coefficient (ADC) values over 10 months, with coefficients of variation (CoVs) below 5%.
• ADC values exhibited dependence on diffusion time, with distinct averages at 12 ms and 45 ms.
• Microstructural parameters showed higher variability (CoVs up to 13%), indicating potential bias in sphere size estimation.

Conclusions:

• A novel, stable biomimetic phantom has been successfully developed, maintaining integrity for up to 10 months.
• This phantom is a promising tool for investigating microstructural models relevant to tumor tissue characterization.
• Potential applications include validating DW-MRI acquisition protocols and inter-scanner comparisons of diffusion-derived biomarkers.