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Tumor

Zeiss Brain Tumor Research Award: Intraoperative confocal laser endomicroscopy during resection of low-grade and nonenhancing brain tumors in eloquent brain regions

Sunday, May 5, 2024
1:57 PM – 1:59 PM CT
Location:  S405a
Disclosure(s):
Irakliy Abramov, MD, PhD: No financial relationships to disclose
Mark Preul, MD: No financial relationships to disclose
Introduction: Despite the advances in intraoperative imaging technologies, resection of low-grade and nonenhancing brain tumors (LGNE) from eloquent regions still remains a neurosurgical challenge. The decision making process during surgeries in such cases relies on balancing the greater extent of tumor resection without compromising postoperative functional outcomes. Intraoperative confocal laser endomicroscopy (CLE) can be used to differentiate LGNE tumor tissue from normal brain tissue during microsurgical resection.

Methods: This retrospective study describes our experience with application of CLE during surgical resection of LGNE located in eloquent brain regions (precentral gyrus, supplementary motor area, hypothalamus, and brainstem). CLE was used to image various areas of brain tumors, including deep and superficial tumor margins and tumor core. Tissue was biopsied co-localized to imaging locations, and interpretations of CLE imaging was compared to permanent histological sections by a CLE-experienced neuropathologist.

Results: Overall, CLE imaging was used in 9 patients with LGNE [diffuse astrocytoma (n=2), pilocytic astrocytoma (n=2), subependymoma, choroid plexus papilloma, hemangioblastoma and oligodendroglioma (n=2)] in eloquent regions, and 10 tumor margin and 5 tumor core regions (2257 images) were assessed. Overall concordance between permanent histological sections from the corresponding regions of interest (ROI) and CLE imaging was observed in 11 of 15 (73%) ROI; at margins in 8 of 10 (80%) ROI; at tumor core in 3 of 5 (60%) ROI. Sensitivity/specificity of CLE for interpretation of LGNE in the eloquent zones were 75%/ (47-91), and 66% (12-98), respectively. Positive/negative predictive values for CLE imaging were 90% (60-99), and 40% (71-77), respectively.

Conclusion : CLE imaging can assist in the intraoperative identification of histopathological features consistent with cellular atypia in eloquent brain regions. The ability of CLE digital optical biopsies to provide real-time examination of brain tissue histoarchitecture without the need to extract tissue samples, has the potential to enhance postoperative functional outcomes.