Sensitive J-coupled metabolite mapping using Sel-MQC with selective multi-spin-echo readout.

Area of Science:

• Magnetic Resonance Imaging
• Metabolomics
• Biophysics

Background:

• Selective multiple quantum coherence (SMQC) is a powerful technique for metabolite editing in Magnetic Resonance Imaging (MRI).
• Traditional SMQC methods can be time-consuming, limiting their application in fast or 3D imaging.
• Accelerating SMQC acquisition while maintaining sensitivity and spectral quality is crucial for advanced MRI applications.

Purpose of the Study:

• To develop and validate a novel method combining SMQC with a read gradient to accelerate metabolite measurements.
• To compare the sensitivity of SMQC with and without a read gradient at high magnetic field strengths.
• To assess the utility of the new technique for metabolite imaging and T(2) relaxation measurements in phantoms and in vivo.

Main Methods:

• Integration of a read gradient with the selective multiple quantum coherence technique.
• Acquisition of multiple spin-echoes using frequency-selective refocusing for specific metabolite groups.
• Implementation of a phase-shifting scheme to suppress water-related artifacts.
• Experimental validation using phantoms (lactate, polyunsaturated fatty acids) and in vivo tumor imaging at 17.6 T.

Main Results:

• The combined SMQC and read gradient approach significantly accelerates metabolite imaging.
• Frequency-selective refocusing preserves J-modulation, allowing for flexible echo time selection.
• The method successfully edited lactate and polyunsaturated fatty acids in phantoms and imaged lactate content and T(2) in tumors.
• Artifact suppression was achieved using the proposed phase-shifting scheme.

Conclusions:

• The developed technique offers a fast and sensitive method for selective multiple quantum coherence editing.
• This approach enhances the feasibility of 3D SMQC experiments and T(2) mapping of metabolites.
• The method holds significant potential for in vivo metabolic imaging, particularly in oncology and other applications requiring rapid, sensitive metabolite detection.