A nested phosphorus and proton coil array for brain magnetic resonance imaging and spectroscopy

Area of Science:

• Medical Imaging
• Neuroscience
• Biophysics

Background:

• Phosphorus magnetic resonance spectroscopy (31P MRS) is crucial for assessing brain energy metabolism.
• Current coil technology limits whole-brain 31P MRS due to sensitivity and coverage constraints.
• Ultra-high field (7T) MRI offers enhanced signal but requires optimized radiofrequency (RF) coil designs.

Purpose of the Study:

• To develop and evaluate a novel dual-nuclei (phosphorus/proton) RF coil array for 7T human brain MRI.
• To improve sensitivity and coverage for both phosphorus spectroscopy and proton imaging.
• To enable advanced quantitative techniques like creatine kinase reaction rate measurement and volumetric metabolic imaging.

Main Methods:

• Construction of an eight-channel birdcage coil for phosphorus (31P) and a nested eight-channel coil for proton (1H) imaging.
• Implementation of a saturation transfer technique for creatine kinase (CrK) forward rate calculation.
• Acquisition of whole-brain 31P metabolite imaging at 1.4cm nominal resolution and 1H anatomical imaging at 1mm isotropic resolution.

Main Results:

• The dual-nuclei coil achieved whole-brain coverage and improved 31P sensitivity compared to standard coils.
• Phosphorus spectroscopy enabled quantitative assessment of the global CrK forward reaction rate.
• Simultaneous 1H imaging provided high-resolution anatomical localization, and 31P imaging achieved 2.3cm actual resolution in 15 minutes.

Conclusions:

• The developed multi-channel coil array enhances both coverage and sensitivity for 7T brain 31P and 1H applications.
• This technology facilitates volumetric assessment of brain energy metabolism.
• Potential for new insights into neurodegenerative diseases (e.g., Alzheimer's, Parkinson's) and mental disorders (e.g., schizophrenia).