Introduction: Rapid and reliable tumor tissue identification during neurosurgical operation is a challenging problem. Volume of resection is one of the most important factors for tumor control and precision of tumor/normal tissue border determination is extremely important. Ambient ionization mass spectrometry based on situ fingerprinting of tissue is an attractive solution.
Methods: A special spray-from-tissue ambient ionization method was developed. In this ionization source liquid extraction is immediately followed by ionization. For preliminary characterization of method and formation of database more than 200 different tumors samples were analyzed. For each sample, mass spectra were measured in both FTICR (high and ultra-high resolution) and in ion trap modes. Fragmentation methods were used for deeper analysis and identification of peaks in mass spectra. Final validation of database profiles was performed using ultrahigh resolution FTICR methods developed in our group previously.
Results: It was demonstrated that MS profile analysis of brain tissue samples gives sufficient information for the identification of tissue and the type of pathology as well as for theirs combination. One of the most important methodological results of the database accumulation stage of the project is the conclusion that in the boundary regions of each tumor the MS profiles can be represented as a linear combination of two and more profiles from different types of cells (necrotic tissue with necrotized vessels, necrotic tissue with tumor stain, tumor with necrosis (with a predominance of tumor tissue), necrotized tumor (with a predominance of necrotic masses), parts of tumor cells).
Conclusions: In our work we demonstrate the possibility to use high and ultrahigh resolution data (accurate mass and fine isotopic structure of mass spectra) to identify lipids, metabolites and other compounds giving molecular signatures of the whole tissue.
Patient Care: Mass spectrometry profiling could become one of possible methods for development of technology for intraoperative navigation and characterization of removed tissues and theirs rapid identification and develop novel precise methods of brain tumor surgery
Learning Objectives: Mass spectrometry profiling could become one of possible methods for development of technology for intra surgery control and characterization of dissected tissues and theirs rapid identification.