Accurate 1H tumor spectra quantification from acquisitions without water suppression

Abstract

Monovoxel magnetic resonance spectroscopy (MRS) is a technique extensively used for the study of brain tumors in many imaging centers. However, given the fact that monovoxel spectrum quality depends upon voxel size, region of acquisition and the presence of metal and/or blood residue after surgery can make the comparison of MRS brain tumor spectra more difficult than that of other pathologies. This study was conducted in order to evaluate whether it is possible to predict in which cases a tumor spectrum will be quantifiable from acquisitions obtained without water suppression, allowing comparison to other spectra. Three different methods were employed: a qualitative, clinical method and two quantitative ones (Amares and Quest). It was found that by using Quest, it is possible to estimate the number of acquisitions needed to obtain a quantifiable spectrum before its acquisition, something which was not feasible with Amares (given the base used). On examining the spectra as physicians would, it was found that after a certain number of acquisitions, they did not change. The study shows that it is possible to optimize MRS acquisition time in brain tumors and guarantee spectrum quantification for comparison of different MRS studies, obtained both from a single patient or different patients.