Implementation of an absolute brain 1H-MRS quantification method to assess different tissue alterations in multiple...

Area of Science:

• Neuroimaging
• Biochemistry
• Neurology

Background:

• Multiple sclerosis (MS) involves early, diffuse brain alterations.
• Neurodegenerative pathogenesis in MS highlights the need for specific metabolite measurements.
• Quantifying metabolites in large brain volumes is crucial for understanding MS pathology.

Purpose of the Study:

• To implement an absolute quantification method for metabolite concentrations using localized magnetic resonance spectroscopy (MRS).
• To assess metabolic alterations in different MS subtypes and normal subjects.
• To identify potential biomarkers for progressive MS onset.

Main Methods:

• Developed and validated an absolute quantification MRS method with short (30 ms) and long (135 ms) echo times.
• Included external calibration and corrections for phased-array coil sensitivity and cerebrospinal fluid.
• Validated methodology using simulated brain images with lesions.
• Analyzed metabolite concentrations in 65 MS patients (relapsing-remitting, primary-progressive, secondary-progressive) and 23 controls.

Main Results:

• Increased concentrations of choline (Cho), creatine, and myo-inositol were observed in primary-progressive (PP) and secondary-progressive (SP) MS patients compared to controls.
• N-acetyl compounds (NA) concentrations remained constant across groups.
• Elevated Cho concentration and Cho/tNA ratio were identified as potential markers for progressive MS onset.

Conclusions:

• Absolute quantification MRS provides sensitive detection of metabolic alterations in MS.
• Cho concentration and Cho/tNA ratio show promise as biomarkers for identifying progressive MS.
• These findings suggest new avenues for the detection and monitoring of neurodegenerative processes in MS.