Metabolic alterations in the peritumoral brain in cases of meningiomas: 1H-MRS study

The objective of the present study was metabolic characterization of the peritumoral brain in the vicinity of meningiomas using proton magnetic resonance spectroscopy ((1)H-MRS). Data of long-echo (TR: 2000 ms, TE: 136 ms) single-voxel spectroscopic investigations were obtained during preoperative examination of 81 patients (19 men and 62 women; mean age, 56.5 years). Twenty-seven neoplasms were disclosed incidentally. Moderate-to-severe peritumoral edema was presented in 20 cases. Invasive growth of the tumor was macroscopically identified during surgery in 35 cases. Analyzed metabolites included N-acetylaspartate (NAA), choline-containing compounds (Cho), mobile lipids (Lip) and lactate (Lac). Compared to distant normal-appearing white matter (1)H-MRS of the brain in the vicinity of meningiomas disclosed statistically significant decrease of NAA content (P=0.0019). Investigated metabolic parameters depended on the presence of invasive tumor growth and prominent peritumoral edema, as well as on the size of the neoplasm, its location, and the patient's age. More severe (1)H-MRS-detected peritumoral metabolic abnormalities associated with invasive growth of meningioma might be used for its prediction. The presence of meningioma-related neurological symptoms was mainly determined by the size of the tumor, while might be also associated with lower normalized NAA/Cho ratio and more frequent presence of a Lip peak in the peritumoral brain. In conclusion, decrease of NAA content constitutes the most prominent (1)H-MRS-detected brain abnormality in the vicinity of intracranial meningiomas. Peritumoral spectroscopic alterations are determined by a variety of factors, can be predictive for invasive tumor growth and may correspond to presented neurological symptoms.