Assessing Precision of Metabolite Quantification at 3 Tesla Using ¹H-MRS: Comparative Analysis of PRESS versus Semi-LASER and TE-Averaging

Schizophrenia (SZ) is a chronic psychiatric disorder involving multiple brain regions. Heschl’s gyrus (HG) is central to auditory processing, and has been linked to auditory hallucinations, thus relevant for metabolite assessment. The thalamus (TH) is interconnected with various brain regions and is involved in cognition and motivation. Reduced glycine (GLY), which can cause NMDA receptor hypofunction, is believed to contribute to cognitive and negative SZ symptoms, motivating efforts in measuring GLY in the TH. ¹H-MRS at 3 Tesla was used to evaluate metabolite variability and reproducibility in healthy participants by comparing PRESS and semi-LASER in the HG. Semi-LASER produced higher-quality spectra with smaller residuals and improved metabolite estimates. In the TH, TE-averaging was used to enhance GLY while minimizing myo-inositol overlap. Although some metabolites were quantified reliably, GLY exhibited broad, difficult-to-resolve peaks, and poor reproducibility. Further optimization is required for accurate GLY quantification in the TH at 3 Tesla.

Name thesis:degree_name

Master of Science (M.Sc.)

Level thesis:degree_level

Master's

Discipline thesis:degree_discipline

Physics

Grantor dc:publisher

Carleton University

Year dc:date.issued

2026

Author dc:creator

• Vajda, Elias Avraham

Statement dc:rights

• Copyright © 2026 the author(s). Theses may be used for non-commercial research, educational, or related academic purposes only. Such uses include personal study, distribution to students, research and scholarship. Theses may only be shared by linking to the Carleton University Institutional Repository and no part may be copied without proper attribution to the author; no part may be used for commercial purposes directly or indirectly via a for-profit platform; no adaptation or derivative works are permitted without consent from the copyright owner.

Language dc:language.iso

en

DOI

10.22215/etd/2026-17025

OAI identifier oai:identifier

oai:carleton.scholaris.ca:20.500.14718/45182