Abstract

Abstract BACKGROUND The aim of this clinical trial was to compare Fluorescein-stained intraoperative confocal laser endomicroscopy (CLE) of intracranial lesions and evaluation by a neuropathologist with routine intraoperative frozen section (FS) assessment by Neuropathology. METHODS In this phase II non-inferiority, prospective, multicenter, non-randomized, off-label clinical trial (Eudra-CT: 2019-004512-58), patients above the age of 18 years with any intracranial lesion scheduled for elective resection were included. The diagnostic accuracies of both CLE and FS referenced with the final histopathological diagnosis were statistically compared in a non-inferiority analysis, representing the primary endpoint. Secondary endpoints included the safety of the technique and time expedited for CLE and FS. RESULTS 210 patients were included by 3 participating sites between November 2020 and June 2022. Most common entities were high grade gliomas (37.9%), metastases (24.1%), and meningiomas (22.7%), A total of 6 serious adverse events in 4 (2%) patients were recorded. For the primary endpoint, the diagnostic accuracy for CLE was inferior with.87 versus.91 for FS, resulting in a difference of.04 (95% confidence interval -.10;.02; p=.367). The median time expedited until intraoperative diagnosis was 3 minutes for CLE and 27 minutes for FS, with a mean difference of 27.5 minutes (standard deviation 14.5; p<.001). CONCLUSION CLE allowed for a safe and time-effective intraoperative histological diagnosis with a diagnostic accuracy of 87% across all intracranial entities included. The technique achieved histological assessments in real-time with a tenfold reduction of processing time compared to FS, which may invariably impact surgical strategy on the fly.