Multivendor implementation and comparison of volumetric whole‐brain echo‐planar MR spectroscopic imaging

Abstract

Purpose To assess volumetric proton MR spectroscopic imaging of the human brain on multi-vendor MRI instruments. Methods Echo-planar spectroscopic imaging (EPSI) was developed on instruments from three manufacturers, with matched specifications and acquisition protocols that accounted for differences in sampling performance, RF power, and data formats. Inter-site reproducibility was evaluated for signal-normalized maps of N-acetylaspartate (NAA), Creatine (Cre) and Choline using phantom and human subject measurements. Comparative analyses included metrics for spectral quality, spatial coverage, and mean values in atlas-registered brain regions. Results Inter-site differences for phantom measurements were under 1.7% for individual metabolites and 0.2% for ratio measurements. Spatial uniformity ranged from 79% to 91%. The human studies found differences of mean values in the temporal lobe, but good agreement in other white-matter regions, with maximum differences relative to their mean of under 3.2%. For NAA/Cre, the maximum difference was 1.8%. In grey-matter a significant difference was observed for frontal lobe NAA. Primary causes of inter-site differences were attributed to shim quality, B0 drift, and accuracy of RF excitation. Correlation coefficients for measurements at each site were over 0.60, indicating good reliability. Conclusion A volumetric intensity-normalized MRSI acquisition can be implemented in a comparable manner across multi-vendor MR instruments.

Physiological neuronal decline in healthy aging human brain — An in vivo study with MRI and short echo-time whole-brain 1H MR spectroscopic imaging

“…These results may provide reference data for studies on patients with brain disorders, with appropriate consideration for scanner and pulse sequence differences. A recent study, however, showed that the volumetric EPSI sequence and the data processing used here can be implemented across multivendor MR scanners and resulted in comparable numerical results (Sabati et al, 2015). …”

Big GABA: Edited MR spectroscopy at 24 research sites

“…These focuses have included: unedited, short-TE MRS (Deelchand et al, 2015); low-field MRS (Träber et al, 2006); ultra-high field MRS (van de Bank, 2015); absolute quantification (Bovée et al, 1998; De Beer et al, 1998; Keevil et al, 1998; Soher et al, 1996); MRSI (Sabati et al, 2015; Wijnen et al, 2010); body MRS (Bolan et al, 2016; Scheenen et al, 2011); brain tumor classification (García-Gómez et al, 2009; Julià-Sapé et al, 2006; Tate et al, 2003; Vicente et al, 2013); and HIV-associated dementia (Chang et al, 2004; Lee et al, 2003; Sacktor et al, 2005). Even for short-TE methods, the degree of agreement between sites and scanners is highly dependent on the degree of acquisition homogeneity.…”

Metabolic voxel‐based analysis of the complete human brain using fast 3D‐MRSI: Proof of concept in multiple sclerosis

“…Although metabolite maps were not expressed in absolute concentrations, due to the requirement that this would greatly increase acquisition times, our approach provides normalized maps of individual metabolites using the interleaved water signal acquired during the 3D-EPSI sequence (8) as a reference that can be implemented across multiple sites (6). As a proof of concept, this study has validated statistical mapping analysis as applied to whole brain 3D-EPSI as an in vivo and non-invasive means to characterize the topography of metabolic disorders in neurological diseases and its relationship with clinical deficit.…”

“…While these methods provide improved spatial coverage there remain limitations for sampling of the entire brain (6). Nevertheless, partial brain sampling has been reported to be sufficient to conduct statistical mapping analyses comparing metabolic maps between different group of healthy subjects (7).…”