Manganese-enhanced magnetic resonance imaging (MEMRI)

Area of Science:

• Neuroscience
• Biomedical Imaging
• Biophysics

Background:

• Manganese ions (Mn2+) have been utilized as MRI contrast agents for over two decades.
• Manganese-enhanced MRI (MEMRI) emerged in the late nineties for brain activity and neuronal tracing applications.
• MEMRI is a valuable tool in biological systems research.

Purpose of the Study:

• To detail the methodological approaches for utilizing MEMRI in biological systems.
• To highlight the three primary applications of MEMRI: anatomical contrast enhancement, activity-dependent assessment, and neuronal tract tracing.

Main Methods:

• MEMRI utilizes the paramagnetic properties of Mn2+ ions to enhance T1-weighted MRI contrast.
• Mn2+ acts as a calcium (Ca2+) analog, entering excitable cells via voltage-gated Ca2+ channels.
• Intracellular Mn2+ is transported along axons and can cross synapses, enabling neuronal tracing.

Main Results:

• MEMRI provides excellent T1 contrast enhancement due to Mn2+ accumulation.
• The technique allows for activity-dependent assessment in excitable cells like neurons and cardiac cells.
• Axonal transport and trans-synaptic transfer of Mn2+ facilitate neuronal connection tracing.

Conclusions:

• MEMRI is a versatile imaging technique with established applications in neuroscience and beyond.
• The unique properties of Mn2+ ions underpin MEMRI's utility in visualizing cellular and network-level biological processes.
• Understanding MEMRI methodologies is crucial for its effective application in biological research.