Correlations between DTI-derived metrics and MRS metabolites in tumor regions of glioblastoma: a pilot study.

Correlations between DTI-derived metrics and MRS metabolites

Abstract

Introduction. Specific correlations among diffusion tensor imaging (DTI)-derived metrics and magnetic resonance spectroscopy (MRS) metabolite ratios in brains with GB (glioblastoma) are still not completely understood.  

Materials and Methods. Retrospective cohort study. MRS ratios (Cho/NAA, LL/Cr, and mI/Cr) were correlated with eleven DTI biomarkers: mean diffusivity (MD), fractional anisotropy (FA), pure isotropic diffusion (p), pure anisotropic diffusion (q), the total magnitude of the diffusion tensor (L), linear tensor (Cl), planar tensor (Cp), spherical tensor (Cs), relative anisotropy (RA), axial diffusivity (AD) and radial diffusivity (RD) at the same regions: enhanced rim, peritumoral oedema and normal-appearing white matter. Correlational analyses of 546 MRS and DTI measurements used Spearman coefficient.

Results. At the enhancing rim we found four significant correlations: FA Û LL/Cr, Rs = -.364, p = .034; Cp Û LL/Cr, Rs = .362, p = .035; q Û LL/Cr, Rs = -.349, p = .035; RA Û LL/Cr, Rs = -.357, p = .038. Another ten pairs of significant correlations were found in the peritumoral edema: AD Û LL/Cr, AD Û mI/Cr, MD Û LL/Cr, MD Û mI/Cr, p Û LL/Cr, p Û mI/Cr, RD Û mI/Cr, RD Û mI/Cr, L Û LL/Cr, L Û mI/Cr.

Conclusions. DTI and MRS biomarkers answer different questions; peritumoral oedema represents the biggest challenge with at least ten significant correlations between DTI and MRS that need additional studies. The fact that DTI and MRS measures are not specific of one histologic type of tumour broadens their application to a wider variety of intracranial pathologies.