Time-Dependent Influence of Cell Membrane Permeability on MR Diffusion Measurements

Area of Science:

• Biophysics
• Magnetic Resonance Imaging
• Cell Biology

Background:

• Cell membrane permeability is a critical factor influencing diffusion measurements in biological tissues.
• Understanding this influence is crucial for accurate interpretation of diffusion MRI data.

Purpose of the Study:

• To investigate how cell membrane permeability affects diffusion measurements across various diffusion times.
• To determine the optimal diffusion time for minimizing the impact of membrane permeability.

Main Methods:

• Human K562 cells were treated with saponin to alter membrane permeability.
• Diffusion MRI measurements were performed using oscillating gradient spin echo (OGSE) and stimulated echo acquisition modes.
• Effective diffusion times ranged from 0.42 to 3000 ms, complemented by computer simulations.

Main Results:

• The impact of membrane permeability on diffusion measurements is strongly dependent on the diffusion time.
• This influence becomes negligible only when the diffusion time is significantly shorter than the intracellular exchange lifetime.

Conclusions:

• Cell membrane permeability minimally affects apparent diffusion coefficient (ADC) measurements using OGSE at higher frequencies.
• Conversely, membrane permeability significantly influences ADC values obtained with conventional pulsed gradient methods at lower frequencies.