The prognosis of glioblastoma patients highly depends on resection extent. Various strategies have been introduced to overcome the dilemma of intraoperative tumor identification.

In gastroenterology, confocal laser endomicroscopy (CLE) allows precise differentiation of tumor tissue from surrounding mucosa in various diseases. Combining high-definition white light endoscopy with CLE significantly increases sensitivity and specificity compared with the sole application of high-definition white light endoscopy.

CLE was recently introduced to neurosurgical applications. Although still in an early stage of clinical application, this technique has proven to be capable of differentiating various tumor entities in animal models as well as human tissue samples. CLE allows visualization of the underlying tissue on a microscopic scale, receiving information on the microstructure as well as cellular components. However, the clinical importance of this technique for its application in neurosurgery will be demonstrated in this clinical trial.

Background:

The prognosis of glioblastoma patients highly depends on resection extent. Various strategies have been introduced to overcome the dilemma of intraoperative tumor identification.

In gastroenterology, confocal laser endomicroscopy (CLE) allows precise differentiation of tumor tissue from surrounding mucosa in various diseases. Combining high-definition white light endoscopy with CLE significantly increases sensitivity and specificity compared with the sole application of high-definition white light endoscopy.

CLE was recently introduced to neurosurgical applications. Although still in an early stage of clinical application, this technique has proven to be capable of differentiating various tumor entities in animal models as well as human tissue samples. CLE allows visualization of the underlying tissue on a microscopic scale, receiving information on the microstructure as well as cellular components. However, the clinical importance of this technique for its application in neurosurgery still needs to be demonstrated

Methods:

Intravenous injection dose of fluorescein sodium. For every operation the investigators plan to take pictures with the CONVIVO system before taking the material for standard frozen section and definitive histopathology. These pictures will be evaluated by a pathologist afterwards.

Objectives:

The primary objective of this trial is to demonstrate, that the CONVIVO system allows identification of tumor tissue. The secondary objectives are procedural aspects and handling issues covering the usability.

Inclusion Criteria:

• The patient is undergoing neurosurgery for a suspected brain tumor and amenable to surgical resection by fluorescent guided technique
• The patient has an indication for tumor resection
• Macroscopic tumor visualization using sodium fluorescein is planned, concentration 5-10mg/kg
• The patient is older than 18 years
• Written consent

Exclusion Criteria:

• Stereotactic biopsy procedure
• Patients with any kind of contraindication to the use of fluorescein sodium
• Vulnerable persons (pregnant women, patients with Glasgow Coma Scale below 14)
• Participation in other ongoing clinical trials with one exception: double inclusions are allowed provided that no interaction with NaF is to be expected
• People who do not want to participate in the study
• Tumors that do not exactly match the inclusion criteria
• Emergency procedures in which no consent was obtained before the operation.
• Multiple surgeries on the same patient.