Diffusion Tensor Imaging with Fluorescein Sodium Staining in the Resection of High-Grade Gliomas in Functional Brain Areas

Intraoperative Fluorescein Sodium in Pediatric Neurosurgery: A Preliminary Case Series from a Singapore Children’s Hospital

(1) Background: Fluorescein sodium (Na-Fl) has been described as a safe and useful neurosurgical adjunct in adult neurooncology. However, its use has yet to be fully established in children. We designed a study to investigate the use of intraoperative Na-Fl in pediatric brain tumor surgery. (2) Methods: This is a single-institution study for pediatric brain tumor patients managed by the Neurosurgical Service, KK Women’s and Children’s Hospital. Inclusion criteria consists of patients undergoing surgery for suspected brain tumors from 3 to 19 years old. A predefined intravenous dose of 2 mg/kg of 10% Na-Fl is administered per patient. Following craniotomy, surgery is performed under alternating white light and YELLOW-560 nm filter illumination. (3) Results: A total of 21 patients with suspected brain tumours were included. Median age was 12.1 years old. For three patients (14.3%), there was no significant Na-Fl fluorescence detected and their final histologies reported a cavernoma and two radiation-induced high grade gliomas. The remaining patients (85.7%) had adequate intraoperative fluorescence for their lesions. No adverse side effects were encountered with the use of Na-Fl. (4) Conclusions: Preliminary findings demonstrate the safe and efficacious use of intraoperative Na-Fl for brain tumors as a neurosurgical adjunct in our pediatric patients.

Maximal Safe Resection in Glioblastoma Surgery: A Systematic Review of Advanced Intraoperative Image-Guided Techniques

Glioblastoma multiforme (GBM) represents the most common and aggressive central nervous system tumor associated with a poor prognosis. The aim of this study was to depict the role of intraoperative imaging techniques in GBM surgery and how they can ensure the maximal extent of resection (EOR) while preserving the functional outcome. The authors conducted a systematic review following PRISMA guidelines on the PubMed/Medline and Scopus databases. A total of 1747 articles were identified for screening. Studies focusing on GBM-affected patients, and evaluations of EOR and functional outcomes with the aid of advanced image-guided techniques were included. The resulting studies were assessed for methodological quality using the Risk of Bias in Systematic Review tool. Open Science Framework registration DOI 10.17605/OSF.IO/3FDP9. Eighteen studies were eligible for this systematic review. Among the selected studies, eight analyzed Sodium Fluorescein, three analyzed 5-aminolevulinic acid, two evaluated IoMRI imaging, two evaluated IoUS, and three evaluated multiple intraoperative imaging techniques. A total of 1312 patients were assessed. Gross Total Resection was achieved in the 78.6% of the cases. Follow-up time ranged from 1 to 52 months. All studies assessed the functional outcome based on the Karnofsky Performance Status scale, while one used the Neurologic Assessment in Neuro-Oncology score. In 77.7% of the cases, the functional outcome improved or was stable over the pre-operative assessment. Combining multiple intraoperative imaging techniques could provide better results in GBM surgery than a single technique. However, despite good surgical outcomes, patients often present a neurocognitive decline leading to a marked deterioration of the quality of life. Advanced intraoperative image-guided techniques can allow a better understanding of the anatomo-functional relationships between the tumor and the surrounding brain, thus maximizing the EOR while preserving functional outcomes.

Specular Reflection Suppression through the Adjustment of Linear Polarization for Tumor Diagnosis Using Fluorescein Sodium

In tumor surgery, the edges of the tumor can be visually observed using a fluorescent contrast agent and a fluorescent imaging device. By distinguishing it from normal tissues and blood vessels, it is possible to objectively judge the extent of resection while visually observing it during surgery, and it guarantees safe tumor resection based on more information. However, the main problem of such an imaging device is the specular reflection phenomenon. If specular reflection overlaps with important lesion locations, they are a major factor leading to diagnostic errors. Here, we propose a method to reduce specular reflection that occurs during tumor diagnosis using a linear polarization filter and fluorescent contrast agent. To confirm the effect of removing specular reflection, a self-made fluorescein sodium vial phantom was used, and the reliability of the results was increased using a large animal (pig) test. As a result of the experiment, it was possible to obtain an image in which specular reflection was removed by controlling the rotation angle of the filter by 90° and 270°, and the same results were confirmed in the phantom experiment and the animal experiment.

Fluorescein-Guided Resection of High Grade Gliomas: A Meta-Analysis

BACKGROUND

High-grade gliomas (HGGs) have a poor prognosis despite current standard of care of surgery, chemotherapy, and radiation therapy. Achieving gross total resection (GTR) has been found to prolong survival in these patients. Intraoperative fluorescent agents are often used to aid in the resection of HGGs. One commonly used fluorescent agent is fluorescein sodium, which is U.S. Food and Drug Administration-approved for ocular surgeries and has a better side effect profile and is less costly than 5-aminolevulinic acid (5-ALA). In this meta-analysis, we provide statistical evidence of the efficacy in using fluorescein for HGG resection.

METHODS

Following the PRISMA framework, we assessed 119 reports from PubMed, Medline (Ovid), and BIOSIS Citation Index and found 21 eligible studies for meta-analysis, assessing the rates of GTR with fluorescein-guided resection of HGGs.

RESULTS

A pooled cohort of 336 patients underwent fluorescein-guided HGG resection with a GTR rate of 81% (95% confidence interval 73%-89%; P < 0.001). Ten case-controlled studies were analyzed, showing a 29.5% increase in GTR rate in the fluorescein group compared with non-fluorescein-guided surgeries.

CONCLUSIONS

This meta-analysis shows that fluorescein-guided surgery improves GTR rates of HGGs when compared with non-fluorescence guided surgery and has similar GTR rates when compared with reported 5-ALA-guided resection rates.

Fluorescein-guided resection of gliomas

Standard of care in the management of high-grade gliomas includes gross total resection (GTR) followed by treatment with radiation and temozolomide. GTR remains one of the few independent prognostic factors for improved survival in this disease. Sodium fluorescein is an organic fluorophore that has been studied as a surgical adjunct to improve the likelihood of achieving GTR in gliomas. Though sodium fluorescein does not selectively accumulate in glioma cells, it allows for real-time identification of regions of blood brain barrier breakdown, corresponding to the contrast-enhancing cores of high-grade gliomas. In addition to its high predictive value for identifying pathologic tissue, use of fluorescein has been shown to improve rates of GTR. In stereotactic needle biopsies, it helps reduce procedure time by rapidly confirming the presence of diagnostic tissue. Furthermore, in non-enhancing, low-grade gliomas, it labels focal regions of vascular dysregulation that have been correlated with high-grade features. Fluorescein has also been shown to be significantly less expensive than other contemporary surgical adjuncts such as intraoperative ultrasound, intraoperative MRI, and the recently FDA approved fluorophore, 5-aminolevulinic acid (5-ALA). Here, we review the current literature on the effectiveness of fluorescein as a surgical tool in the resection of gliomas.