Current density imaging sequences with separation of mobile-ion current from immobile-ion current

Area of Science:

• Magnetic Resonance Imaging (MRI)
• Biophysics
• Electrochemistry

Background:

• Electric current density imaging (CDI) is crucial for understanding charge transport.
• Distinguishing between resistive and capacitive current components is challenging.
• Existing CDI methods lack selectivity for different charge carrier types.

Purpose of the Study:

• To develop and evaluate novel MRI sequences for selective electric current detection.
• To differentiate between resistive and capacitive current components in biological systems.
• To introduce a new MRI contrast mechanism based on ion mobility.

Main Methods:

• Development of three electric current density imaging (CDI) sequences: DC-CDI, AC-CDI, and a novel AC-DC-CDI.
• Utilizing square voltage pulses and refocusing radiofrequency (RF) pulses to modulate current detection.
• Experimental validation using a model system to assess current component selectivity.

Main Results:

• DC-CDI sequence selectively detected resistive currents from mobile ions.
• AC-DC-CDI sequence selectively detected capacitive currents from fixed ions.
• AC-CDI sequence detected both resistive and capacitive current components.

Conclusions:

• The developed CDI sequences provide a new MRI contrast mechanism dependent on ion mobility.
• These methods enable selective detection of different electric current types in biological systems.
• The techniques hold significant potential for studying electric conductivity in biological tissues.