Single-shot multiparametric MRI for separating T₂ effects from dynamic glucose-enhanced contrast

Area of Science:

• Biomedical Imaging
• Magnetic Resonance Imaging
• Metabolic Imaging

Background:

• Glucose is a key metabolic substrate and a biomarker for diseases.
• Dynamic glucose-enhanced (DGE) MRI using chemical exchange saturation transfer (CEST) maps glucose uptake.
• Quantification of DGE-MRI is complicated by glucose-induced T2 relaxation changes.

Purpose of the Study:

• To develop and validate a multiparametric CEST (MP-CEST) MRI method for accurate glucose uptake quantification.
• To correct for T2 relaxation confounding effects in DGE-MRI.
• To improve the specificity and robustness of metabolic imaging.

Main Methods:

• Developed a single-shot MP-CEST MRI sequence using multi-echo SPEN for simultaneous T2 and proton density (PD) map acquisition.
• Implemented a two-step correction strategy using saturation-weighted PD maps and T2 maps with Bloch-McConnell simulations.
• Validated the framework in phantom and in vivo rat brain and tumor xenograft models.

Main Results:

• Achieved high accuracy in T2 and PD quantification (R2 > 0.99) in phantoms.
• Demonstrated significant reduction in the correlation between DGE signals and T2 values in vivo.
• Showcased improved specificity of glucose-related contrast and complementary physiological information from T2 maps.

Conclusions:

• The MP-CEST approach enhances the accuracy and robustness of DGE quantification.
• This method offers a more comprehensive framework for metabolic imaging.
• The technique is applicable to oncological and neurological research.