Global brain metabolic quantification with whole‐head proton MRS at 3 T

Abstract

SUMMARY NAA, Cr and Cho 1H-MRS signals are often used as surrogate markers in diffuse neurological pathologies, but spatial coverage of this methodology is limited to 1%–65% of the brain. Here we wish to demonstrate that non-localized, WH 1H-MRS, captures just the brain’s contribution to the Cho and Cr signals, ignoring all other compartments. Towards this end 27 young healthy adults (18 men, 9 women), 29.9±8.5 years old, were recruited and underwent T1-weighted MRI for tissue segmentation, non-localizing, ~3 minute WH 1H-MRS (TE/TR/TI= 5/104/940 ms) and 30 min 1HMRSI (TE/TR=35/2100 ms) in a 360 cm3 VOIs at the brain's center. The VOI absolute NAA and Cr and Cho concentrations: 7.7±0.5, 5.5±0.4 and 1.3±0.2 mM, were all within 10% of the WH: 8.6±1.1, 6.0±1.0 and 1.3±0.2 mM. The mean NAA/Cr and NAA/Cho ratios in the WH were only slightly higher than the “brain-only” VOI: 1.5 versus 1.4 (7%) and 6.6 versus 5.9 (11%); Cho/Cr were not different (0.2 for both). The brain/WH volume ratio was 0.31±0.03 (brain ≈30% of WH volume). Air-tissue susceptibility-driven local magnetic field changes going from the brain outwards showed sharp ›100 Hz/cm (1 ppm/cm) gradients, explaining the skull’s Cr and Cho signal losses through, resonance shifts, line broadening and destructive interference. The similarity of non-localized WH and localized VOI NAA, Cr and Cho concentrations and their ratios, suggest that their signals originate predominantly from the brain. Therefore, the fast, comprehensive WH-1H-MRS method may facilitate quantification of these metabolites, which are common surrogate markers in neurological disorders.

Whole brain neuronal abnormalities in focal quantified with proton MR spectroscopy

“… Bottom : Same from their age and gender matched controls (numbers 18, 22 and 23 in Table 2). Note (i) the small residuals (reflecting VeSPA fit’s quality), that are likely due to the limited number of metabolites in the fitting basis set; and possible lineshape differences between the measured in vivo peaks and the assumed Voight basis functions used by the VeSPA software; (ii) excellent lipid suppression performance; and (iii) while the acquisition is non-localizing, the metabolites’ spectra come from the brain only (Kirov et al, 2017). …”

“…We address all these issues with a non-localizing 1 H-MRS sequence that acquires the whole-head signal (Gonen et al, 1998; Soher et al, 2014), and that has recently been shown to yield contributions from only the whole-brain (WB), the compartment of interest (Kirov et al, 2017). In this paper, we use the recently developed full spectral-modeling for WB 1 H-MRS (Soher et al, 2014), in order to test the hypothesis that despite lack of atrophy, brains of patients with localization-related epilepsy incur neuronal dysfunction well beyond the ictal zone, reflected by a decrease in their global NAA concentration.…”

Whole-brain MR spectroscopic imaging reveals regional metabolite abnormalities in perinatally HIV infected young adults

“…By comparison, studies of brain metabolite concentrations in PHIV using proton magnetic resonance spectroscopy (MRS) were less common (Van den Hof et al, 2019). MRS allows for the acquisition of various metabolites, including N-acetylaspartate (NAA) as a proxy for neuronal density and viability, total choline (tCho) as an indicator of cell membrane turnover and gliosis, and total creatine (tCre) as a marker for cellular energy metabolism (Kirov et al, 2017). In general, contradictory findings have emerged from MRS studies of neurometabolites in PHIV (Keller et al, 2004;Nagarajan et al, 2012;Iqbal et al, 2016;Mbugua et al, 2016;Van Dalen et al, 2016;Robertson et al, 2018;Van den Hof et al, 2019;Graham et al, 2020).…”

Role of Radiological Intervention in Brain Tumor: A Meta-Analysis

“…It shows the different ratios present in the studies. Such as Vallée et al, [21] Di Costanzo, [22] Huang [23] andMatsusue[18] radiological findings reported results for rCBV, Cho/NAA, and Cho/Cr while Elias[24] and Kirov et al[25] reported on Cho/Cr and Cho/NAA. Whereas, Alexiou et al,…”