MR THERMOMETRY OF THE BRAIN: ANALYSIS OF WATER SUPPRESSION IN SINGLE VOXEL SPECTROSCOPY

• Published in: Acta neurobiologiae experimentalis Vol. 82; p. XLIII
• Main Authors: Sińczuk, Marcin, Rogala, Jacek, Hryniewicz, Nikodem, Piątkowska‑Janko, Ewa, Bogorodzki, Piotr
• Format: Journal Article
• Language: English
• Published: Warsaw Polish Academy of Sciences 01-01-2022
• Subjects: Brain; Brain mapping; Calibration; Choline; Creatine; Data acquisition; Estimates; Functional magnetic resonance imaging; In vivo methods and tests; Metabolites; Spectra; Spectroscopy; Spectrum analysis; Thermometry; Water analysis
• ISSN: 0065-1400; 1689-0035

In a typical PRESS (Point RESolved Spectroscopy) sequence the water signal is suppressed to allow for metabolite peak quantification. On the other hand, water peak parameters are useful in further metabolite quantification or other specific studies like MR thermometry. Our study compared temperature estimates from two MR spectra with either suppressed or unsuppressed water peaks. We investigated how suppression pulses influence temperature estimates and whether suppressed or unsuppressed water peaks should be used in future MRS thermometry studies. Six calibration datasets were acquired from the phantom. Each uses suppressed and unsuppressed water peaks in conjunction with metabolites: NAA, Creatine, and Choline. In vivo data was acquired from 169 healthy adult subjects with PRESS sequence. Two spectra were acquired from each subject: One before 30 minute fMRI study and one after. Mean brain temperatures (in vivo) showed similar significant negative changes between pre and post-fMRI sessions. Comparisons reveal that unsuppressed water data yields higher temperatures and higher deviations overall than suppressed water data. We believe that using suppressed water peak data (where water peak is still visible) is preferable but it is also feasible to use spectra with unsuppressed water peak in conjunction with metabolites from highly suppressed spectral data.