In Vivo Absolute Metabolite Quantification Using a Multiplexed ERETIC-RX Array Coil for Whole-Brain MR Spectroscopic...

Area of Science:

• Medical Imaging
• Biophysics
• Neuroscience

Background:

• Absolute quantification of metabolites in Magnetic Resonance Spectroscopic Imaging (MRSI) necessitates a stable reference signal.
• The Electronic REference To access In vivo Concentrations (ERETIC) system shows promise but requires adaptation for patient studies and 3D MRSI.
• Technical challenges in integrating ERETIC hardware with receive arrays, including coil combination and channel coupling, were addressed.

Purpose of the Study:

• To develop and validate absolute quantification methods for whole-brain MRSI in glioma patients.
• To assess the performance of ERETIC in conjunction with a custom-built receive array for metabolite quantification.

Main Methods:

• A prospective study involving healthy volunteers and glioma patients using a 3T scanner with 3D MRSI and real-time motion correction.
• A custom-built 4x-ERETIC/8x-receive array coil was employed for absolute quantification of key brain metabolites and 2-hydroxyglutarate.
• Comparison of ERETIC-based quantification with internal water reference methods using Bland-Altman analysis and statistical testing.

Main Results:

• Successful integration of ERETIC with receive arrays was achieved, with inductive coupling identified as the dominant interference.
• Phantoms demonstrated proportional scaling of the ERETIC signal with coil loading.
• Excellent agreement between ERETIC and internal water quantification was observed in healthy volunteers, but significant differences were noted in glioma tumors.

Conclusions:

• The integration of ERETIC with receive arrays is feasible for brain metabolite quantification using whole-brain MRSI.
• Further research is required to validate the accuracy of ERETIC for metabolite concentration measurements in glioma patients.