Abstrakt
Title: Magnetic resonance spectroscopy in the preliminary intracranial tumor analysis.
Petra hnilicova
Magnetic resonance spectroscopy (MRS) enables non-invasive biochemical insight in oncologic processes. In this study, we evaluated the clinical manifestation of intracranial tumors based on in vivo proton (1H) and phosphorus (31P) MRS examination. Five patients (60±10 years) with intracranial tumors (3 glioblastomas, 2 metastasis) underwent MR performed on a 1.5 T MR scanner (Siemens). For both MRS, the 3D multivoxel sequences were carried out: in 1H MRS: PRESS, TR/TE=1500/135 ms, 0.52 ml voxels, 20 min; in 31P MRS: FID, TR/TE=290/2.3 ms, 27 ml voxels, 30 min. For one voxel localized inside the tumor and another one in the normal-appearing brain tissue, both 1H and 31P MR spectra were evaluated in LCModel and jMRUI, respectively. Quantification of tumor metabolism showed a significant decrease of N-acetyl-aspartate to the Creatine ratio, demonstrating loss of neuro-axonal viability. Significant increase of Choline-containing compounds (i.e., Phosphocholine) to the Creatine ratio proved changes in cell proliferation, accompanied by greater levels of membrane phospholipids synthesis (high ratios of Phosphomonoesters to Phosphodiesters and Phosphomonoesters to Adenosine triphosphate) as their degradation (low ratios of Phosphodiesters to Adenosine-triphosphate). Furthermore, energetic tissue demands and anaerobic metabolic turnover, were shown as decreased levels of Phosphocreatine (ratio to Adenosine-triphosphate) and increased production of Lactate (ratio to Creatine). A combination of 1H and 31P MRS enables the comprehensive metabolic characterization of intracranial tumors.