Intraoperative tissue identification using rapid evaporative ionization mass spectrometry.

Area of Science:

• Biotechnology
• Analytical Chemistry
• Oncology

Background:

• Rapid evaporative ionization mass spectrometry (REIMS) is an emerging technology for near real-time tissue analysis.
• The intelligent knife (iKnife) couples REIMS with electrosurgery for in vivo tissue diagnostics.
• Validating REIMS for ex vivo and in vivo surgical applications is crucial for clinical adoption.

Purpose of the Study:

• To validate the REIMS technique for analyzing human tissue samples ex vivo.
• To demonstrate the translation of REIMS technology for real-time in vivo surgical diagnostics.
• To assess the accuracy of intraoperative tissue identification using the iKnife system.

Main Methods:

• Analysis of 302 patient tissue samples ex vivo, creating a database of 1624 cancerous and 1309 non-cancerous spectra.
• Deployment of the iKnife system in an operating theater for data collection during 81 surgical resections.
• Application of multivariate statistical methods (PCA, LDA) for mass spectrometric data analysis and spectral identification.

Main Results:

• REIMS accurately differentiated between distinct histological and histopathological tissue types.
• Malignant tissues exhibited chemical characteristics specific to their histopathological subtypes.
• Intraoperative REIMS tissue identification achieved 100% concordance with postoperative histological diagnoses in all 81 cases.
• Mass spectra revealed lipidomic profiles varying between tumor types and between primary and metastatic tumors, suggesting divergent tumor biochemistry.

Conclusions:

• The REIMS technique, as implemented in the iKnife, is a validated tool for accurate real-time tissue diagnosis during surgery.
• The technology provides reliable intraoperative identification of tissue types, matching gold-standard histology.
• REIMS offers insights into tumor lipidomics and biochemistry, potentially aiding in understanding cancer mechanisms.