Reproducibility of phase rotation STEAM at 3T: Focus on glutathione

Abstract

Purpose The purpose of this study was to determine the reproducibility of a very short echo time (TE) phase rotation stimulated echo acquisition mode (STEAM) sequence at 3T with a focus on the detection of glutathione. Methods Ten healthy subjects were scanned on two separate visits. Spectra were acquired from voxels placed in the anterior and posterior cingulates. Reproducibility was assessed using mean coefficients of variation (CVs) and mean absolute differences (ADs), and reliability was assessed using standard error of measurement (SEM) and intraclass correlations (ICCs). Phantoms containing glutathione and metabolites with overlapping resonances were scanned to test the validity of glutathione quantification. Results Excellent reproducibility as illustrated by CVs ≤8.3% and ADs ≤11.6% for both regions was obtained for glutathione and other commonly reported metabolites. Reproducibility measures for γ-aminobutyric acid and glutamine were good overall with CVs ranging from 6.4%–10.5% and ADs ranging from 8.6%–15.5% for both regions. Glutathione absolute and relative reliability were very good (SEMs ≤9.9%) and fair (ICCs 0.42–0.51), respectively. Phantom studies demonstrated the ability to accurately detect glutathione from other metabolites with overlapping resonances with great precision (R2 = 0.09). Conclusion A very short TE phase rotation STEAM sequence proved reproducible for metabolites difficult to quantify but important for the study of psychiatric and neurological illness.

Reproducibility of quantitative structural and physiological MRI measurements

“…Previous efforts demonstrated high scan–rescan reproducibility of the neuroimaging included of the volumetric measurements for subcortical brain structures (Maclaren et al., 2014), cortical gray matter thickness (Dickerson et al., 2008; Han et al., 2006; Li et al., 2015), and diffusion tensor measurements (Acheson et al., 2017; Jovicich et al., 2014). Likewise, several prior studies quantified scan–rescan stability and reproducibility of the MRS measurements at 3T (Wellard, Briellmann, Jennings, & Jackson, 2005; Wijtenburg & Knight‐Scott, 2011; Wijtenburg et al., 2013). Our approach of three scanning sessions and tightly controlled methodological parameters provides for the opportunity to assess these measurements based on the normal physiological variance among them.…”

Evaluation of Myo-Inositol as a Potential Biomarker for Depression in Schizophrenia

“…Metabolite levels are reported in institutional units (i.u.). Previously, we have shown that the VTE PR-STEAM method produces excellent reproducibility as determined by a test-retest study (Wijtenburg et al, 2014). There were no significant group differences in the quality of the spectra and metabolite fits.…”

“…Imaging studies suggest that the medial prefrontal/ACC is a critical component of neural networks that regulates mood and emotionally influenced behavior in depression (Sacher et al, 2012;Phillips et al, 2003) and also a critical region associated with cognitive and emotional impairment in schizophrenia (Fornito et al, 2009;Reid et al, 2010;Carter et al, 2001;Phillips et al, 2003). Spectra were acquired using very short TE (VTE) phase rotation (PR) STEAM sequence: TR/TM/TE = 2000/10/6.5-ms, NEX = 128, 2.5-kHz spectral width, 2048 complex points, and phases: φ1 = 135°, φ2 = 22.5°, φ13 = 112.5°, φADC = 0° ( Wijtenburg and Knight-Scott, 2011;Wijtenburg et al, 2014). A water reference (NEX = 16) was also acquired for phase and eddy current correction as well as quantification.…”

Frontal Glutamate and γ-Aminobutyric Acid Levels and Their Associations With Mismatch Negativity and Digit Sequencing Task Performance in Schizophrenia

“…The event-related potential and MRS methods have been described previously, 33,36,52 and details are given in the eMethods in the Supplement. Briefly, the event-related potential was recorded using a 64-channel system 2 (SynAmps; Compumedics Neuroscan) at a 1-kHz sampling rate with bandpass at 0.1 to 200 Hz.…”

“…33 Glutamate levels, including the ratio of glutamine to glutamate, were assessed with an MRS technique optimized for the detection of these metabolites. 34-36 The ratio of glutamine to glutamate is thought to reflect glutamatergic neurotransmission whereby the ratio of conversion from glutamine to glutamate may index glutamatergic function. 37 In schizophrenia, a higher ratio of glutamine to glutamate has been found in the cerebrospinal fluid 38 and brain tissue measured with MRS in some studies 39-42 but not in another study.…”