Fitting algorithms and baseline correction influence the results of non ‐invasive in vivo quantitation of 2‐hydroxyglutarate with 1H‐MRS

Quantitation of 2 ‐HG levels showed similar mean tissue concentrations for IDH mutated tumors (2.65mM, range 3.06 – 2.20) for all methods. Bland Altman plots did not reveal a systematic bias for any of the algorithms tested. We showed a significant correlation regarding 2‐HG concentration with few statistical o utliers. However, evaluation of outliers suggested that in vivo quantitation of 2‐HG is not only affected by analysis domains, but also by baseline correction being a major contributing factor to 2‐HG fit. 1H ‐MRS enables non‐invasive detection of 2‐hydroxyglutarate (2‐HG), an oncometabolite accumulating in gliomas carrying mutations in the isocitrate dehydrogenase (IDH) genes. Reliable 2‐HG quantitation requires reproducible post‐processing, deployment of fitting algorithms and quantitation methods. We prospectively enrolled 38 patients with suspected or recently diagnosed gliomas (IDH mutatedn = 26). The MRI protocol included a1H single voxel PRESS sequence with volumes of usually 8  mL or more (20 × 20 × 20 mm3) atTE = 97 ms and 180° pulse spacing. Our aim was to evaluate the reliability of 2‐HG quantitation comparing two frequently used software tools and their respective options of baseline correction (jMRUI with the time domain methods AQSES and QUEST, and LCModel, which analyzes the frequency domain d ata). For AQSES, degrees of freedom for baseline correction constrains were varied. For LCModel, baseline correction was obta...
Source: NMR in Biomedicine - Category: Radiology Authors: Tags: RESEARCH ARTICLE Source Type: research