MRSI of a 69-year-old woman (Patient 1) with a glioblastoma multiforme (GBM) lesion. (A) Pre-surgical spectra demonstrate increased choline, decreased N-acetylaspartate (NAA) and the presence of lactate. At 5 weeks (B) and 27 weeks (C) post-treatment with resection and Gliadel Wafer implantation, spectral data showed a reduction of metabolites in the resection cavity