Deuterium brain imaging at 7T during D₂O dosing

Abstract

Purpose: To characterize the ( 2 H) deuterium MR signal measured from human brain at 7T in participants loading with D 2 O to ∼1.5% enrichment over a six-week period. Methods: 2 H spectroscopy and imaging measurements were used to track the time-course of 2 H enrichment within the brain during the initial eight-hour loading period in two participants. Multi-echo gradient echo (MEGE) images were acquired at a range of TR values from four participants during the steady-state loading period and used for mapping 2 H T 1 and T 2 * relaxation times.Co-registration to higher resolution 1 H images allowed T 1 and T 2 * relaxation times of deuterium in HDO in cerebrospinal fluid (CSF), gray matter (GM), and white matter (WM) to be estimated.Results: 2 H concentrations measured during the eight-hour loading were consistent with values estimated from cumulative D 2 O dose and body mass. Signal changes measured from three different regions of the brain during loading showed similar time-courses. After summing over echoes, gradient echo brain images acquired in 7.5 minutes with a voxel volume of 0.36 ml showed an SNR of ∼16 in subjects loaded to 1.5%. T 1 -values for deuterium in HDO were significantly shorter than corresponding values for 1 H in H 2 O, while T 2 * values were similar. 2 H relaxation times in CSF were significantly longer than in GM or WM. Conclusion:Deuterium MR Measurements at 7T were used to track the increase in concentration of 2 H in brain during heavy water loading. 2 H T 1 and T 2 * relaxation times from water in GM, WM, and CSF are reported. heavy water, human brain, MEGE, relaxation timesThis is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Whole‐brain deuterium metabolic imaging via concentric ring trajectory readout enables assessment of regional variations in neuronal glucose metabolism

“…The 3D maps of 2 H Glc and Glx concentration estimates (in mM) were created for all time points. Voxel‐wise concentration estimation was performed using natural abundance water maps from the beginning of the DMI protocol (first and second time point for PE‐DMI and CRT‐DMI, respectively) as internal reference according to (Gasparovic et al, 2006 ) assuming relaxation times and in vivo concentrations from literature (Cocking et al, 2023 ; Seres Roig et al, 2023 ) ( 2 H:water: T 1GM / T 1WM / T 1CSF = 320/290/510 ms, T 2GM/WM / T 2CSF = 30/90 ms, Glx: T 1 / T 2 = 149/53 ms, Glc: T 1 / T 2 = 66/44 ms, 2 H water concentration: 17.2 mM). The number of deuterium atoms per molecule was accounted for, see Appendix 1 .…”

Reproducibility of 3D MRSI for imaging human brain glucose metabolism using direct (2H) and indirect (1H) detection of deuterium labeled compounds at 7T and clinical 3T

“…Concentration estimates were calculated as presented in (34), using natural abundance deuterated 2 H water (averaged over the first 3 time points) and 1 H total creatine as internal reference, for 7T DMI and 3T QELT, respectively. Relaxation times and in vivo concentrations were assumed using literature values (9,14,(35)(36)(37): ([ 2 H: waterT1/T2=350 ms/30 ms, GlxT1/T2=150 ms/40 ms, GlcT1/T2=67 ms/42 ms, 2 H water concentration: 17.2 mM] , [ 1 H T1: tCrGM/WM= 1.46 s/1.24 s, GlxGM/WM= 1.27 s/1.24 s, T2: tCrGM/WM = 201 ms/198 ms, GlxGM/WM= 134 ms/148 ms], tCrGM = 7.5 mM, tCrWM= 5.7 mM). The number of deuterons and protons per molecule contributing to the detected resonance was accounted for.…”