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Magn Reson Med. 2015 Nov;74(5):1209-20. doi: 10.1002/mrm.25510. Epub 2014 Oct 29.

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

Author information

1
Department of Radiology, University of Miami, Miami, Florida, USA.
2
Department of Radiology, University of Calgary, Calgary, Canada.
3
Department of Radiology, Stanford University, Stanford, California, USA.
4
The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, and the F.M. Kirby Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA.
5
Neurology and Radiological Sciences, University of California, Los Angeles, California, USA.

Abstract

PURPOSE:

To assess volumetric proton MR spectroscopic imaging (MRSI) of the human brain on multivendor MRI instruments.

METHODS:

Echo-planar spectroscopic imaging was developed on instruments from three manufacturers, with matched specifications and acquisition protocols that accounted for differences in sampling performance, radiofrequency (RF) power, and data formats. Intersite 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:

Intersite differences for phantom measurements were less than 1.7% for individual metabolites and less than 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 gray matter, a significant difference was observed for frontal lobe NAA. Primary causes of intersite 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 multivendor MR instruments.

KEYWORDS:

MR spectroscopic imaging; MR standardization; clinical equivalency; multicenter studies; quantitative mapping

PMID:
25354190
PMCID:
PMC4414683
DOI:
10.1002/mrm.25510
[Indexed for MEDLINE]
Free PMC Article

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