Repeatability of edited lactate and other metabolites in astrocytoma at 3T

Abstract

Purpose: To assess the repeatability of measurement of lactate and other metabolites in tumors using magnetic resonance spectroscopy (MRS).Materials and Methods: MRS with spectral editing for lactate was performed on 10 patients with astrocytoma (two Grade III, eight Grade IV) using an 8-channel receive coil at 3T. Lactate, lipid, choline, creatine, and N-acetyl aspartate (NAA) signals were measured in regions of tumor and contralateral white matter. Metabolites were quantified relative to unsuppressed water using LCModel fitting software.Results: The within-patient coefficients of variation were %16% (tumor lactate), 6%-8% (tumor choline and contralateral choline, creatine, and NAA), and 22% (tumor lipid). As expected due to their low concentration in normal tissue, lactate and lipid were not reliably detected in white matter but were found at high levels in most tumors. NAA and creatine were lower in tumors than in normal white matter, and choline varied between above-and below-normal values. No consistent short-term variation in metabolite levels was observed, despite differences in the time elapsed since administration of contrast agent.Conclusion: MRS appears repeatable enough to provide longitudinal measures of metabolite content in tumors and contralateral tissue in the brain in vivo.

Quantifying the CDK inhibitor VMY-1-103’s activity and tissue levels in an in vivo tumor model by LC-MS/MS and by MRI

“…Other key metabolites were not significantly affected. Choline levels are abundant in the MBs of this mouse model, 24 and studies have established that the levels of choline levels are relatively consistent both in brain tumors and in normal brain tissue, 25 - 27 and our data support these finding. N-acetylaspartate (NAA) is a marker of neuronal metabolism and the relative levels of NAA were unaffected by VMY treatment, suggesting that VMY did not have an overall adverse effect on the brain, as levels of NAA would be expected to change.…”

Utility of multiparametric 3-T MRI for glioma characterization

“…Although widely used as a concentration standard, there is regional and individual variability in concentration 21 and it has been shown to be decreased in tumors 22 , however higher Cre values relative to NAWM values were associated with shorter survival 23 . The results of this study indicate that when ROIs were selected based on minimum creatine and NAA, the classifications based on either the signal normalized Cre or normalized to the value in NAWM achieved the highest specificity of the MRS measures.…”

Edited1H magnetic resonance spectroscopy in vivo: Methods and metabolites

“…Its low concentration and the macromolecule signals at 1.24 and 1.43 ppm limit the detection of lactate in typical, healthy brain . Lactate has been measured using MEGA‐PRESS , single and dual BASING , MQF , and polarization transfer . In these editing methods, the editing pulse is applied at 4.1 ppm, and the signal of the 1.33 ppm peak is detected.…”