Intraoperative imaging of brain tumors with fluorescein: confocal laser endomicroscopy in neurosurgery. Clinical and user experience

Abstract

OBJECTIVEConfocal laser endomicroscopy (CLE) is an established tool in basic research for tissue imaging at the level of microstructures. Miniaturization and refinement of the technology have made this modality available for operative imaging with a handheld device. Sufficient image contrast is provided by the preoperative application of fluorescein sodium. The authors report their first experiences in a clinical case series using the new confocal laser endomicroscope.METHODSHandling, operative workflow, and visualization of the CLE were critically evaluated in 12 cases of different CNS tumors. Three different imaging positions in relation to the tumor were chosen: the tumor border (I), tumor center (II), and perilesional zone (III). Respective diagnostic sampling with H & E staining and matching intraoperative neuronavigation and microscope images are provided.RESULTSCLE was found to be beneficial in terms of high-quality visualization of fine structures and for displaying hidden anatomical details. The handling of the device was good, and the workflow was easy.CONCLUSIONSHandling ergonomics and image acquisition are intuitive. The endomicroscope allows excellent additional visualization of microstructures in the surgical field with a minimally invasive technique and could improve safety and clinical outcomes. The new confocal laser endomicroscope is an advanced tool with the potential to change intracranial tumor surgery. Imaging of these microstructures is novel, and research with comparative validation with traditional neuropathological assessments is needed.

High-Dose Fluorescein Reveals Unusual Confocal Endomicroscope Imaging of Low-Grade Glioma

“…In conjunction with dedicated fluorescein filters on surgical microscopes, the increasing use of intraoperative histopathologic examination with confocal laser endomicroscopy (CLE) using FNa has produced a tool for optically interrogating gliomas with a sensitivity and specificity comparable to the examination of a frozen section (14)(15)(16)(17)(18). Our institutional experience with CLE and low-dose FNa has been similar to that of others, albeit inconsistent for nonenhancing lesions and LGG.…”

“…However, in this case report, we describe a situation in which high-dose FNa was administered during resection of an oligodendroglioma with the use of CLE, which produced unusually clear images of the LGG. This report contributes to the limited evidence for the possible use of FNa to visualize Abbreviations: CLE, confocal laser endomicroscopy; FET-PET, 18 F-fluoroethyl-L-tyrosine-positron emission tomography; FLAIR, fluid-attenuated inversion recovery; FNa, fluorescein sodium; HGG, high-grade gliomas; IDH, isocitrate dehydrogenase; LGG, low-grade gliomas; MRI, magnetic resonance imaging; WHO, World Health Organization; 5-ALA, 5-aminolevulinic acid.…”

Confocal Laser Microscopy in Neurosurgery: State of the Art of Actual Clinical Applications

“…In 2020 an appropriate sterile sheath became available for the Convivo system by Zeiss (new generation system, with an increased lateral resolution of about 0.5 µm and Z-axis resolution of about 4.5 µm and an automatic Z-stack acquisition function). Convivo system was used in the last in vivo work available in the literature, by Hohne and colleagues [ 24 ]. The authors evaluated the handling, operative workflow and visualization of Convivo system in 12 cases of different CNS tumors.…”

The Neurosurgeon’s Armamentarium for Gliomas: An Update on Intraoperative Technologies to Improve Extent of Resection

“…In a study of 74 patients who underwent resection with laser endomicroscopy and fluorescein sodium, there was a sensitivity and specificity for gliomas of 91% and 94%, respectively [17]. Additionally, confocal laser endomicroscopy has been shown to be not only effective in high-quality visualization, but ergonomically friendly to surgeons with ease of use [134].…”