Clinical use of MRSI is limited by the level of experience required to properly translate MRSI examinations into relevant clinical information. To solve this, several methods have been proposed to automatically recognize a predefined set of reference metabolic patterns. Given the variety of metabolic patterns seen in glioma patients, the decision on the optimal number of patterns that need to be used to describe the data is not trivial. In this paper, we propose a novel framework to (1) separate healthy from abnormal metabolic patterns and (2) retrieve an optimal number of reference patterns describing the most important types of abnormality. Using 41 MRSI examinations (1.5 T, PRESS, T E 135 ms) from 22 glioma patients, four different patterns describing different types of abnormality were detected: edema, healthy without Glx, active tumor and necrosis. The identified patterns were then evaluated on 17 MRSI examinations from nine different glioma patients. The results were compared against BraTumIA, an automatic segmentation method trained to identify different tumor compartments on structural MRI data. Finally, the ability to predict future contrast enhancement using the proposed approach was also evaluated. KEYWORDS applications, cancer, head and neck cancer methods and engineering, MRS and MRSI methods, post-acquisition processing, spectroscopic imaging, visualization methods and engineering 1 | INTRODUCTION MRS provides relevant metabolic information for the assessment of brain tumors, allowing us to distinguish different tumor types and grades, 1-3 distinguish radiation effects (pseudoprogression) from true progression 4,5 and identify regions with high tumor cellularity that are not visible in structural MRI. 6-8 Many publications 9 focus on the translation of one or two MRS features, such as choline (Cho)/NAA (N-acetyl aspartate) andCho/Cr (creatine), into clinically meaningful information for the tasks described above. Regardless of what can already be achieved with the analysis of individual metabolite ratios, the use of metabolic patterns for the identification of tissue types and diseases has the potential to allow more precise characterization of brain tumors.Several approaches 10-21 have been suggested for the analysis of metabolic patterns present in brain tumor MRS data. Before such methods can be used to interpret new data, a library of metabolic patterns has to be defined. The decision on the order of the model used to interpret .3 + Lip0.9; Lip0.9, 0.9 ppm signals originating from the -CH3 moiety of lipid molecules (triglycerides); Lip1.3, 1.3 ppm signals originating from the -CH2 moiety of lipid molecules (triglycerides); LOH, loss of heterozygosity; LOOCV, leave-one-out cross-validation; NAA, N-acetyl aspartate; NNLS, non-negative least squares