P15.08.B Intraoperative confocal laser endomicroscopy of brain tumors - potential and challenges from a neuropathological perspective

• Published in: Neuro-oncology (Charlottesville, Va.) Vol. 24; no. Supplement_2; p. ii85
• Main Authors: Maragkou, T, Quint, K, Pollo, B, Hewer, E
• Format: Journal Article
• Language: English
• Published: US Oxford University Press 05-09-2022
• Subjects: POSTER PRESENTATIONS
• ISSN: 1522-8517; 1523-5866
• DOI: 10.1093/neuonc/noac174.298

Abstract
Background
Intraoperative consultation, usually in the form of a frozen section, is an integral part of current neuropathology practice. Typical indications include determination of specimen adequacy, intraoperative diagnosis and distinction between tumoral and non-tumoral tissue in diffusely infiltrating gliomas in tumor periphery. The latter is currently limited by the fact that typically not all potential regions of interest can be sampled for frozen sections and the turnaround times of frozen sections usually do not permit multiple repetitive assessments. The commercial availability of a clinical-grade in vivo laser endomicroscope for neurosurgical applications may have the potential to change this and to permit a microscopic analysis in near-real time, which in turn may have a significant impact on resection strategies for brain tumors. In this work, we investigate the potential role of CLE in neurosurgery and the transferability of histological criteria to confocal imaging.
Material and Methods
The potential role of CLE in neurosurgery in comparison to other techniques for intraoperative tumor assessment was determined by analyzing common intraoperative neuropathological workflows and identifying unaddressed opportunities. The transferability of the histological criteria from standard histology to confocal imaging was achieved by analyzing matched image pairs (standard histology and CLE) from several common tumor entities.
Results
We identified the time gap between specimen resection and the availability of the frozen section results as an important application for intraoperative CLE imaging in neurosurgery. Importantly, neuropathologists could assess tissue in near real time in an unlimited number of digital biopsies prior to resection, which adds a potent new tool to the neurosurgical armamentarium. CLE images revealed features similar to already known tissue architecture/morphology seen in standard histology, which correlated well in matched histological images. Unique aspects of individual cells and other surrounding tumor tissue elements were observed in vivo while the CLE probe acquired images throughout its focal-depth range.
Conclusion
Widespread application of CLE may have a major impact on neuropathologists' role in intraoperative diagnosis and bring along both opportunities and challenges. For broad clinical adoption, strategies for histological criteria validation as well as for determination of diagnostic accuracy need to be developed.