title: Real time analysis of brain tissue by direct combination of ultrasonic surgical aspiration and sonic spray mass spectrometry.
abstract: Direct combination of cavitron ultrasonic surgical aspirator (CUSA) and sonic spray ionization mass spectrometry is presented. A commercially available ultrasonic surgical device was coupled to a Venturi easy ambient sonic-spray ionization (V-EASI) source by directly introducing liquified tissue debris into the Venturi air jet pump. The Venturi air jet pump was found to efficiently nebulize the suspended tissue material for gas phase ion production. The ionization mechanism involving solely pneumatic spraying was associated with that of sonic spray ionization. Positive and negative ionization spectra were obtained from brain and liver samples reflecting the primary application areas of the surgical device. Mass spectra were found to feature predominantly complex lipid-type constituents of tissues in both ion polarity modes. Multiply charged peptide anions were also detected. The influence of instrumental settings was characterized in detail. Venturi pump geometry and flow parameters were found to be critically important in ionization efficiency. Standard solutions of phospholipids and peptides were analyzed in order to test the dynamic range, sensitivity, and suppression effects. The spectra of the intact tissue specimens were found to be highly specific to the histological tissue type. The principal component analysis (PCA) and linear discriminant analysis (LDA) based data analysis method was developed for real-time tissue identification in a surgical environment. The method has been successfully tested on post-mortem and ex vivo human samples including astrocytomas, meningeomas, metastatic brain tumors, and healthy brain tissue.
authors.affiliation: Institute for Inorganic und Analytical Chemistry, Justus-Liebig-University, Giessen, Germany.
authors.forename: Karl-Christian
authors.initials: KC
authors.lastname: Schäfer
authors.forename: Júlia
authors.initials: J
authors.lastname: Balog
authors.forename: Tamás
authors.initials: T
authors.lastname: Szaniszló
authors.forename: Dániel
authors.initials: D
authors.lastname: Szalay
authors.forename: Géza
authors.initials: G
authors.lastname: Mezey
authors.forename: Júlia
authors.initials: J
authors.lastname: Dénes
authors.forename: László
authors.initials: L
authors.lastname: Bognár
authors.forename: Matthias
authors.initials: M
authors.lastname: Oertel
authors.forename: Zoltán
authors.initials: Z
authors.lastname: Takáts
mesh_terms: D001921:Brain / Q000378:metabolism*; D001932:Brain Neoplasms / Q000378:metabolism; D016002:Discriminant Analysis; D006801:Humans; D008113:Liver Neoplasms / Q000378:metabolism; D010455:Peptides / Q000032:analysis; D010743:Phospholipids / Q000032:analysis; D025341:Principal Component Analysis; D013010:Sonication; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: D010455:Peptides; D010743:Phospholipids