Analysis of MRS voxel placements in brain tumors performed by MRS experts

Motivation: There is no standardized way of prescribing MRS voxels in the lesion. This depends entirely on the MR operator’s expertise and opinion. Goal(s): Our goal was to analyze MRS voxel placements in brain tumors for quantitatively reliable and reproducible voxel placement. Approach: MRS experts placed voxels and visually scored their placements. Placements and scores were compared to tumor characteristics. Results: All experts showed a tendency to place the voxels to fill approximately 30% of voxels with tumor core for different participants. The fraction of tumor core in voxels showed a correlation of 0.76 to the fraction of tumor core in the whole tumor. Impact: Quantitative analysis of MRS voxel placement shows that MRS experts deemed a voxel properly placed when tumor core was adequately included, suggesting widely applicable and objective method of voxel placement and assessment for non-experts in clinical settings.